Researchers are using gene microarrays to understand what makes young skin taut and even-toned, and to find out why older epidermis sags, wrinkles, or develops spots. 
They can then hunt for molecules that activate those same genes in aging or sun-damaged skin. 
A number of skin-care lines, such as Olay products, already contain ingredients based on microarray work.
Another way makeup makers develop new products is to examine the metabolism of skin cells. A healthy cell, with active mitochondria, is a comely cell. 
Old cells with fewer or malfunctioning mitochondria look aged. Modern devices can infer metabolic rate based on oxygen consumption and the acidic by-products released by cell cultures into the media in which the cells are grown.
Cultured skin is crucial to in vitro studies of personal-care products. One of the best mimics for the human integument is, not surprisingly, made of human skin. 
Epidermal cells from elective surgery, dissociated and reconstituted, are common in cosmetics labs where scientists daub on new compounds and test the safety of different formulations.
In fact, these days, product safety testing often takes place in a dish. 
Rarely do the methods involve using animals, which has been out of vogue for decades, notes Michael Ingrassia, senior manager for skin biology and drug delivery at Dow Pharmaceutical Sciences in Petaluma, California, where he works on the CeraVe moisturizer line. 
In fact, the desire to limit animal experimentation has driven the development of many modern cosmetics testing methods.
One common goal among cosmetics researchers is to make skin appear fresh and young. 
Signs of aging vary depending on skin tone. Light-skinned consumers are looking to minimize wrinkles, the earliest sign of aging in people with low levels of melanin in the skin. 
Buyers with dark, melanin-filled skin frequently seek products to diminish the darkened spots that appear in their skin before wrinkles.
To develop creams and other anti-aging remedies, researchers working at personal-care product companies use many of the same tools as their counterparts in basic research and pharmaceutical sciences. 
Here, The Scientist profiles four modern methods behind the makeup.
Gene expression microarrays are common tools in the personal- care products industry. 
In fact, Procter & Gamble (P&G) is one of the largest users of Affymetrix gene chips, processing tens of thousands of chips per year, says Jay Tiesman, leader of P&G’s genomics group, based in Mason, Ohio. 
Cosmetics and pharmaceutical industry users may want to look for desirable transcriptome profiles, and then scan chemical libraries for compounds that push cells in that direction.
“Instead of just poking around in the dark—trying ingredients and seeing which ones work—[microarray technology] gives us a real, fundamental understanding of skin biology,” Tiesman says. 
For example, the team has compared old and young skin samples from women’s forearms, where sun damage is an issue, and their buttocks, where it likely is not (Br J Dermatol, 166 Suppl 2:9-15, 2012). 
They discovered that a lipid biosynthesis pathway, involving the production of cholesterol, was downregulated with age and sun exposure. 
The work led to the inclusion of hexamidine, which boosts this pathway, in the Olay Professional Pro-X products.
Skin biopsies are removed from the face or other locations, via scraping with a razor or scalpel, or as a round cutout taken by a small needle or a punch device a bit like a long cookie cutter. 
Researchers isolate the RNA and hybridize it to fingernail-size glass chips holding millions of nucleic acid probes. 
Tiesman’s lab runs so many chips they use a high-throughput, 96-chip format.
Researchers isolate the RNA and hybridize it to fingernail-size glass chips holding millions of nucleic acid probes. 
Tiesman’s lab runs so many chips they use a high-throughput, 96-chip format.
Gene chips provide an unbiased approach. It’s important to be open-minded about where the data might lead you, advises William Swindell of the University of Michigan in Ann Arbor, who uses chips to study psoriasis.
As it’s an established technology, there are plenty of publicly available microarray data to compare to yours.
Gene chips only include probes for known mRNAs; they can’t help you discover new variants.
Skin samples will include more than one cell type, complicating analysis.
“Find a good statistician, and listen to him or her from the beginning,” Tiesman says. Statisticians’ input is important in both study design and analysis.
In addition to the details of gene expression, cosmetics scientists want to understand the ins and outs of cellular metabolism. 
Aging cells slow down metabolically, says Mary Johnson, a principal scientist at P&G. “The overall aging that we experience, a lot of it’s driven by cellular energetics,” she says. 
Ingredients in anti-aging creams and sera promote a healthy metabolic rate, which translates into a youthful appearance.
Johnson uses the Seahorse XF Extracellular Flux Analyzer to monitor cellular metabolism as she investigates new skin-care ingredients. 
Seahorse’s analyzer has replaced tedious experiments in which researchers had to isolate individual mitochondria or use special electrodes to measure oxygen consumption. 
The ease of the Seahorse system ignited an explosion of studies into cellular bioenergetics in the past decade, Johnson says.
The XF analyzer measures two features of metabolic rate via sensors submerged in each well of a disposable 24- or 96-well microplate cartridge. 
It tracks the production of acidic lactate, the final step of glycolysis, as well as the uptake of oxygen as the cell respires. Together, these measures serve as a proxy for ATP production.
Compounds that promote respiration and glycolysis will cause the cells to increase their metabolism and might make skin cells healthier and more attractive.
Make sure cells form a nice monolayer, recommends Eugenia Trushina, who uses the XF Analyzer to study mitochondrial dysfunction in disease at the Mayo Clinic in Rochester, Minnesota. Clumps or empty spots will interfere with good results.
In vitro models of the epidermis are another common tool in the cosmetics industry. 
MatTek Corporation of Ashland, Massachusetts, markets several versions of skin in a dish. 
“This is the only human organ that can be reconstituted in vitro with not too much difficulty,” says Meenhard Herlyn, a tumor biologist who makes his own reconstructed skin cultures for studies of melanoma at the Wistar Institute in Philadelphia, Pennsylvania.
In cosmetics labs, researchers can use the cultures to test how well creams or sera penetrate the skin, by measuring the quantity of ingredients that reach the liquid media on the underside of the skin culture. 
Scientists can also experiment with skin-lightening agents and can check the toxicity of a new formula without using animals. 
A typical toxicity test, for example, involves the application of a tetrazolium dye to skin or other cell cultures. Active, healthy cells change the dye’s color, which is observed after extracting the dye from the treated tissues.
For Herlyn, reconstructed human skin is a crucial tool because no other animal has skin like ours except for pigs—and those are rather large, expensive animals to work with. 
Herlyn makes his cultures out of infant foreskin that has been removed during circumcision. 
He mixes keratinocytes and melanocytes, and cultures them over a base of collagen and fibroblasts. 
When he exposes the culture to air, the keratinocytes move up while the melanocytes remain below, forming a realistic 3-dimensional tissue.
The melanocytes then pump pigment toward the surface, with a good bit of light exposure, “you can give them a real mean tan,” Herlyn says.
If you’d rather buy the skin premade, MatTek manufactures its models from dissociated infant foreskin or adult skin removed during breast reductions and tummy tucks. 
“It’s a thinner, smaller version of human skin,” says Ingrassia, who used the company’s models regularly when he worked for Est?e Lauder.
Cosmetics companies want their products to be as mild and nonirritating as possible. 
The Cytosensor microphysiometer was the first machine of its kind to be tested and approved by US regulators to analyze eye irritation potential, replacing animal testing with assays of cultured mouse fibroblasts. 
The instrument is basically “a fancy pH meter,” says Warren Casey, acting director of the US National Toxicology Program’s Interagency Center for the Evaluation of Alternative Toxicological Methods in Research Triangle Park, North Carolina.
The microphysiometer doesn’t work for hydrophobic materials, which include many cosmetics. 
Therefore, the device is often best suited to test individual ingredients in solution, rather than complete formulations, says Hans Raabe, director of laboratory services at IIVS. 
The microphysiometer is only recommended to identify compounds at the extremes of the irritation scale—either highly irritating or not at all—and can’t distinguish between mild and moderate irritants.
While the Cytosensor is the only device of this type currently approved, Casey would eventually like.
The Cytosensor microphysiometer measures cellular pH to determine the potential of a given substance to irritate the eye. 
Cells are pipetted into 12-mm wells (top), which then fit into the Cytosensor chamber (bottom). 
When normal acid production drops by half, the treatment is considered to have a high degree of irritation.COURTESY OF IIVS, 2013that work similarly, such as the XF Analyzer.
Peptides found in skin can act by different mechanisms of action, being able to function as epidermal or nervous growth factors or even as neurotransmitters. 
Due to the vast functionality of these compounds, there is growing research on bioactive peptides aimed at investigating their uses in products developed for stimulating collagen and elastin synthesis and improving skin healing. 
Thus, a literature search on applications of the most common bioactive peptides used in cosmeceuticals was carried out. 
There is a lack of proper reviews concerning this topic in scientific literature. 
Nine peptides with specific actions on body and facial dysfunctions were described. It could be noted while searching scientific literature that studies aimed at investigating peptides which prevent aging of the skin are overrepresented.
This makes searching for peptides designed for treating other skin dysfunctions more difficult. 
The use of biomimetic peptides in cosmetic formulations aimed at attenuating or preventing different types of skin dysfunctions is a topic where information is still lackluster. 
Even though research on these compounds is relatively common, there is still a need for more studies concerning their practical uses so their mechanisms of action can be fully elucidated, as they tend to be quite complex.
Techniques aimed at extracting, isolating, characterizing, and synthetizing molecules, as well as techniques for the advanced study of molecular structures, were greatly improved after the second half of the last century.
As a result, bioactive peptides or biomimetic peptides were brought to light in the current knowledge. 
Several peptides with remarkable biological activity were synthetized in the last few years. 
They can be used in areas ranging from cosmetics, therapeutics, and immunology to even food sciences. 
Peptides account for 10% of the sales of pharmaceutical companies, which amounts to US$ 25 billion; the commercialization of peptides has been increasing faster than that of small molecules. Up to 2017, the global cosmeceutical market was estimated to have generated around US$ 42.8 billion
In this review, emphasis was given to synthetic peptides that are used in cosmeceutical formulations, which can be named either as bioactive, biomimetic, or topical peptides.
Peptides are short chains of amino acids. 
Some occur naturally in the human body and are known for playing several biological roles, especially as signaling/regulating molecules in a variety of physiological processes, including defense, immunity, stress, growth, homeostasis, and reproduction. 
As examples, there are vasodilators, vasoconstrictors, and other substances that act upon cell metabolism
Biomimetic peptides, on the other hand, are compounds which have an identical amino acid sequence to physiological peptides (oligopeptides with a sequence ranging from 10 to 15 amino acids), but are synthetized biotechnologically. 
They mimic the action of growth factors and cytokines by interacting with their receptors, leading to clinical effects such as the slowing of aging.
 Examples of biomimetic peptides include acetyl decapeptide-3 (Rejuline), oligopeptide-24 (CG-EGP3), oligopeptide-34 (CG-TGP2), and oligopeptide-72 (Boostrin).
Bioactive or topical peptides are also synthetic compounds, but they consist of modified amino acid chains, which improve an already existing physiological function, such as increasing skin permeability, stability, solubility, and better interaction with cell receptors. 
Also, several natural physiological processes are signaled and modulated exclusively by interaction with specific amino acid sequences found in certain peptides and protein fragments. 
Thus, in a technological context, bioactive peptides are becoming increasingly promising as cosmeceuticals with clinical applications in different skin conditions.
The multiple applications of these synthetic compounds, either biomimetic or bioactive, provide treatment options when used in formulations designed for topical applying, preventing, or attenuating the clinical aspects of skin damaged by dysfunctions: aging, hyperpigmentation, increase of body fat, and wrinkle development. These peptides can also stimulate the synthesis of collagen and elastin, improve wound healing, increase fibroblast proliferation, and act as growth factors  or even as tensioning and tightening agents.
Bioactive peptides can be classified according to their mechanism of action in signal, carrier, and neurotransmitter inhibitor peptides.
The goal of this study was to carry out a literature review on bioactive peptides aiming to describe some of their mechanisms of action and possible applications in cosmetic products. 
This review might contribute to future research by summarizing relevant information and making it readily available for professionals and researchers interested in the subject.
Signal peptides have a structure which can be divided in three different domains: a positively-charged amino-terminal domain (region n, 1–5 long residues); a hydrophobic central domain (region h, 7–15 residues); and a polar carboxyl-terminal domain (region c, 3–7 residues). 
This class of peptides is very important due to its ability to open protein channels which allow the translocation of synthetized proteins to their specific site of action.
Vastly used as active compounds in products aimed at preventing aging, signal peptides are a class of peptides capable of stimulating skin fibroblasts, leading to an increased production of collagen and elastic fibers. 
They can also act as growth factors, as they activate protein kinase C, which is the major factor responsible for cell growth and migration. 
Such stimulus occurs whenever the peptide has its amino acids aligned in a specific pattern, as is the case with the sequence valine-glycine-valine-alanine-proline-glycine (VGVAPG), commercially named palmitoyl oligopeptide?, as elastin-derived peptides bind to cytoplasmic fibroblast receptors.
Heptapeptide Acetyl-DEETGEF-OH (Perfection Peptide P7TM), a signal peptide, acts by protecting cell DNA by stimulating Nrf2-dependant antioxidant enzymes.
 This heptapeptide is a competitive inhibitor of the repression factor Keap1 which acts directly upon transcription factor Nrf2, responsible for scavenging free radicals. 
Water in oil emulsions developed with the aid of nanotechnology can contain a very minimal amount of the peptide (0.0014%) initially dispersed in shea butter.
 After exposure to ultraviolet radiation (UV) for two hours, Langerhans cells were reduced in size and more cells were “sunburned” in the skin of subjects treated with placebo.
 In comparison, subjects that had the formulation containing the heptapeptide had the depletion of skin cells reduced by 6%, and the DNA damage of the affected cells was reduced by 20%. 
This study aimed to prove the efficacy of the formulation, and was carried out by Suter and collaborators (2016). 
It is commercialized by Mibelle Biochemistry Group and its INCI (International Nomenclature of Cosmetic Ingredients) name is acetyl sh-heptapeptide-1 (and) hydrogenated lecithin (and) glycerin (and) Butyrospermum parkii (shea) butter (and) phenethyl alcohol (and) ethylhexylglycerin (and) aqua.
Oligopeptide-68 (β-WHITE?, sequence Arg-Asp-Gly-Gln-Ile-Leu-Ser-Thr-Trp-Tyr) is a whitening agent used in cosmetics on skins affected by melasma.
 It inhibits the actions of microphthalmia-associated transcription factor (MITF), a regulator of melanocyte differentiation, by reducing its tyrosinase activity and “slowing down” key enzymes of the pigmentation process. 
As a signal peptide, it interacts well with cells when used at concentrations of 1.0–2.5%. 
Studies were carried out comparing the effects of hydroquinone (HQ) and of oligopeptide-68 associated with diacetyl boldine (DAB), a compound capable of stabilizing tyrosinases.
 Different oil in water emulsion formulations (one containing HQ and another containing peptide and DAB) were applied to the skin of 40 volunteers; the subjects were assessed on the 6th and 12th week of treatment after controlled exposure to radiation. 
The clarifying effects were considered significant, moderate, or slight for 2.6%, 76.3%, and 21.1% of the subjects treated with the formulation containing the oligopeptide, respectively, and these values are higher than those observed in subjects treated with creams containing HQ at concentrations of 2% and 4%. 
This whitening agent is becoming a frequent subject of study in the research and development of cosmetics.
 It is commercialized by Biotec, part of the AQIA Industrial Chemistry group, under INCI name water (and) butylene glycol (and) hydrogenated lecithin (and) sodium oleate (and) oligopeptide-68 (and) disodium EDTA.
Adipocytes found in the hypodermis contain a high amount of lipids, and each is connected to a number of capillary vessels. 
When hyperplasia and hypertrophy of such adipocytes occur, remodeling of the surrounding capillaries and neovascularization must take place, otherwise the lipodystrophy that follows causes the formation of wrinkles which lead to cellulitis.
Tripeptide-41 (Lipoxyn?) activates NF-kB, a nuclear transcription factor which promotes the synthesis of tumor necrosis factor α (TNFα), a cytokine capable of triggering lipolysis. 
The peptide also reduces the expression of C/EBP, a transcription factor essential for adipocyte differentiation; this factor, when bound to PPARγ, contributes to hyperplasia of adipose tissue. 
The peptide also increases the concentration of cAMP, an important intracellular signaling factor that causes lipolysis by promoting the hydrolysis of lipids into triglycerides.
This peptide is also a signal peptide, but there are few completed studies which report on its efficacy.3
It is commercialized by PharmaSpecial?, represented by Caregen, a leading global company in the market of peptides and growth factors. 
Studies carried out by the product developers have been published. 
One such study, for example, was carried out in vivo, describing the application of an emulsion containing 5% of the peptide once a week for 8 weeks, and the volunteer reported having their waist circumference reduced by 5 cm.
Carrier peptides are responsible for transporting and stabilizing oligoelements such as copper and manganese, carrying them to the skin and allowing their intake by epithelial cells. 
Copper is one of the metals which can be transported by such peptides, playing a role on wound healing as well as being a cofactor for enzymes lysyl oxidase, tyrosinase, and superoxide dismutase, which are essential for collagen synthesis, melanogenesis, and superoxide dismutation (antioxidant action). 
Also, these peptides can stimulate key enzyme actions; an example is the tripeptide-copper complex glycyl-l-histidyl-l-lysine-Cu2+ (copper peptide GHK-Cu or copper tripeptide 1), which not only transports copper, but also increases the tissue levels of metalloproteinases, enzymes responsible for degrading the basic components of the extracellular matrix.
The effects of GHK-Cu upon metalloproteinase synthesis (MMP-2) by skin fibroblasts in culture were demonstrated by Sim?on and collaborators (2000). 
In their study, cultivated fibroblasts treated with GHK-Cu showed increased MMP-2 levels. 
This was evidenced by increased levels of MMP2 mRNA and increased secretion of tissue metalloproteinase inhibitors (TIMP-1 and TIMP-2). 
GHK-Cu is also responsible for the remodeling of the extracellular matrix, as it modulates the expression of MMP by acting directly in wound fibroblasts.
A study carried out by Finkley and collaborators (2005) describes the application of facial creams containing GHK-Cu for 12 weeks on 71 volunteers aged between 50 and 59 years, and the results demonstrated a visible reduction of the effects of aging. 
In another study by the same authors, they describe the application of the formulation on the eyes of 41 volunteers using similar experimental conditions. At the same time, placebo and controls containing vitamin K were also applied to the subjects. 
In both studies it was demonstrated that the cream containing GHK-Cu improved the elasticity and tightness of the skin, and also reduced fine lines and deep wrinkles.
These peptides are capable of increasing minimal muscle activity.
 For muscle contraction to occur, vesicles containing neurotransmitter acetylcholine must be released in neuromuscular junctions and interact with SNARE complexes (soluble N-ethylmaleimide-sensitive factor activating protein receptor). 
This process is modulated by a receptor protein, SNAP-25, which is a membrane protein that becomes associated with the vesicle, and directly regulates binding and vesicle fusion involving the SNARE complex. 
Some peptides possess structural similarities to proteins SNAP-25 in the SNARE complexes, and compete for the binding sites of these complexes, leading to the destabilization of their structure and preventing the release of acetylcholine at nervous endings, modulating the actions of this neurotransmitter.
Peptides of this class are used in anti-aging cosmetics due to their attenuating actions on the formation of wrinkles as they promote the involuntary movement of facial muscles. 
These peptides have been shown to specifically inhibit neurosecretion, and therefore have been called neurotransmitter inhibitor peptides.
The bioactive peptide of sequence Acetyl-Glu-Glu-Met-Gln-Arg-ArgNH2, known as acetyl hexapeptide-3, is a compound similar to botulinum toxin A, but it lacks the N-terminal domain of protein SNAP-25, competing for binding to the SNARE complexes modulating its formation, which inhibits the formation of acetylcholine and as a consequence attenuates muscle contraction.
The peptide also attenuates wrinkle development due to involuntary skin movements. 
This results in the inhibition of the release of acetylcholine.
In vivo tests using four lobsters with exposed muscular mass were carried out; the animals were submerged in solutions containing different concentrations of the active peptide, and it could be verified that the amplitude of excitatory post-synaptic potentials was progressively reduced, inhibiting the action of other proteins which are vital for muscle movement.
In another experiment carried out with 20 human subjects for 30 days, the skin application of oil in water emulsions containing the peptide caused a reduction of wrinkle depth by 59% and 71% and size by 41% and 50% for dry and oily skins, respectively, in comparison with placebo controls. 
An area of 1.5 cm2 of skin was subjected to application, which occurred twice a day in a standardized manner. 
The equipment Clinipro Antiaging SD alongside an IMAGE DB system was used for determination of wrinkle depth and width.
This peptide is commercialized by Galena?, a pioneer in the field of distribution of raw materials to pharmaceutical companies, and has the INCI name aqua (and) acetyl hexapeptide-8 (and) phenoxyethanol (and) methylparaben (and) ethylparaben (and) butylparaben (and) propylparaben (and) isobutylparaben.
This peptide is commercialized by Galena?, a pioneer in the field of distribution of raw materials to pharmaceutical companies, and has the INCI name aqua (and) acetyl hexapeptide-8 (and) phenoxyethanol (and) methylparaben (and) ethylparaben (and) butylparaben (and) propylparaben (and) isobutylparaben.
Vanistryl? is the commercial name of formulations containing acetyl tripeptide-30 citrulline and pentapetide-18, which are bioactive peptides used in wrinkle smoothing formulations that act in synergism modulating muscular tension and inhibiting matrix metalloproteinases (MMPs) when applied to the skin. 
Acetyl tripeptide-30 citrulline (Sequence: Lys-α-Asp-Ile-Citrulline) is a signal peptide, while pentapeptide-18 (Sequence: Tyr-D-Ala-Gly-Phe-Leu) is a neurotransmitter inhibitor peptide.
The application of water in oil emulsions to the skin of 12 volunteers with recent stretch marks at the waist and thighs, twice a day for 30 and 60 days and containing these active components at a concentration of 5%, improved the visual aspects of wrinkles by 38.89%, tightness by 70.83%, softness by 133.33%, touch perception by 28.61%, and color by 50.58%. 
Stretch marks were also softened. Complete quantitative and qualitative clinical evaluations were carried out by dermatologists before treatment and after 30 and 60 days of treatment. 
Surface studies (tightness and drying) were performed with the aid of a Visioscan VC98; color studies made use of Mexameter MX18; and skin elasticity analysis was carried out using Soft Mini Three equipment.
As acetyl hexapeptide-3, this peptide is commercialized by Galena? and by LIPOTEC?, a laboratory which has developed several technological compounds, mostly bioactive peptides. 
Its INCI name is water, caprylyl/capryl glucoside, lecithin, glycerin, Pseudoalteromonas ferment extract, acetyl tripeptide-30 citrulline, pentapeptide-18, xanthan gum, caprylyl glycol .
Neurocosmetics are cosmeceuticals which contain synthetic neuropeptides that interact with the nervous system through skin mediators. 
These compounds can play a role in skin homeostasis by activating or inhibiting such mediators. 
Skin responses carried out by mediators are regulated by a neuroendocrine system found in the skin capable of initiating adaptation mechanisms through quick pathways (neural pathways) or slow pathways (humoral pathways), acting at both local and systemic levels. 
Neurocosmetics can act in the central nervous system, being capable of stimulating the nerve endings of the skin, sending pleasure and well-being “feelings” to the hypothalamus, and causing the release of specific substances on the skin which improve the aspect of skin relief.
Skin cells release growth factors and proteins that bind insulin, which are synthetized from proopiomelanocortine (POMC), catecholamines, steroidal hormones, vitamin D, eicosanoids from fat acids, and retinoids from diet carotenoids. 
Skin has developed an autonomous system that responds to local and peripheral stress, which functions by making use of neurotransmitters and hormone peptides in a manner similar to the hypothalamus-hypophysis-adrenal axis
POMC peptides are synthetized by melanocytes, keratinocytes, microvascular endothelial cells, annex epithelial cells, mastocytes, Langerhans cells, fibroblasts, and immune cells, such as monocytes and macrophages. 
POMC, as a precursor protein, leads to the synthesis of several biologically active peptides through a series of enzymatic steps, which are often specific to each tissue, resulting in the formation of melanocyte stimulator hormones (MSHs), corticotrophin (ACTH), and ?-endorphin.
Fatemi and collaborators (2016) demonstrated that a peptide derived from POMC, bPOMC, has anti-inflammatory properties and does not disrupt melanogenesis. 
When skin is exposed to capsaicin, biomimetic peptides are capable of attenuating inflammation by preventing the release of substance P and the actions of IL-8 and IL-1.
The same research group, in a double-blind study, employed 56 healthy volunteers with sensitive skin divided into two groups of 28 volunteers each. Both groups received a facial formulation (0.1 g) containing bPOMC, which was used on the right side of the face, and a placebo formulation, which was used on the left side, applied on clean cheeks from the nasolabial to the outer cheek areas with circular movements twice a day for 14 days.
 The sensorial irritation test (pinching, burning, and itching) was carried out with the application of capsaicin at 3 × 10?4% for 5 min. After the testing period, the authors verified that the group treated with the formulation containing bPOMC had fewer irritation sensations when compared to the control group, further indicating that biomimetic peptides, such as bPOMC, when used in skin formulations, can significantly reduce symptoms from contact dermatitis, which is an issue for several consumers of cosmetics and topic formulations.
This compound is often associated with liposomes, made of a complex of phyto-endorphins responsible for stimulating fibroblast and keratinocyte proliferation, resulting in wrinkle attenuation and increased cell renewal, revitalization, and hydration. 
There are still no conclusive studies on the efficacy of this peptide. 
Some bioactive peptides have already been studied regarding their safety both in vitro and in vivo. 
According to the FDA (Food and Drug Administration), up to 2012, palmitoyl-like peptides have been the most extensively tested molecules regarding safety so far, as they are also commercialized in cosmetic products.
The bioactive acetyl hexapeptide-3 has been studied to some extent. Maia Campos and collaborators (2014) evaluated the safety of this peptide by making use of the primary skin irritation test and the patch test. 
They describe having used a hypoallergenic adhesive tape (50 mm2 area) applied a single time at occlusive conditions to the dorsal area of 27 volunteers (aged between 20 to 59 years) of phototypes II and IV. 
After 48 h, the tape was removed and the visual evaluation of the result was performed when the erythema was no longer was perceptible; no irritation reactions were caused after 48 h of occlusive contact. 
The research group of Blanes-Mira and collaborators, also demonstrated by means of the skin irritation test, reported that the bioactive acetyl hexapeptide-3 is safe to use in an analysis that used botulinum neurotoxin as a control.
Another study of skin irritation carried out with peptide GHK-Cu at a volume of 0.5 mL in an area of 6 cm2 using three male rabbits and a covering tape for 24 h, with readings conducted at 24 and 72 h, demonstrated that this active component is not a skin irritant under the tested conditions.
Bioactive peptides are becoming increasingly popular in the research and development of cosmetic formulations aimed at treating damaged and dysfunctional skin. 
Several companies such as PharmaSpecial?, Galena?, Biotec?, Lipotec?, and Silab? are investing in technologically innovative bioactive peptides, focusing on signal peptides and neurotransmitter inhibitor peptides. 
Bioactive peptides amount to 10% of all sales of pharmaceutical companies.
Any cosmetic products which contain bioactive peptides in their formulations must be submitted to efficacy and safety tests in order to be approved by the National Health Surveillance Agency (ANVISA) and thus allowed to be commercialized. 
However, there is a lack of published studies on such peptides; the most commonly studied peptides are synthetized from palmitoyl, such as palmitoyl oligopeptide, palmitoyl pentapeptide-4, and palmitoyl tetrapeptide-7, and such studies are generally focused on wrinkle attenuation and skin filling.
It was observed that the majority of research studies are focused on the development of anti-aging actives, and there is still room for research to be carried out to evaluate other functions of these actives. 
Studies reporting on the efficacy of bioactive peptides with specific functions and clarifying their mechanisms of action, mostly regarding their actions upon the attenuation of stretch marks and cellulites, are few, which makes it difficult to search for specific functions of bioactive peptides.
Airborne contaminants are predominantly derived from anthropogenic activities, and include carbon monoxide, sulfur dioxide, nitrogen oxides, volatile organic compounds, ozone and particulate matter. 
The exposure to these air pollutants is associated to detrimental effects on human skin, such as premature aging, pigment spot formation, skin rashes and eczema, and can worsen some skin conditions, such as atopic dermatitis.
A cosmetic approach to this problem involves the topical application of skincare products containing functional ingredients able to counteract pollution-induced skin damage. 
Considering that the demand for natural actives is growing in all segments of global cosmetic market, the aim of this review is to describe some commercial cosmetic ingredients obtained from botanical sources able to reduce the impact of air pollutants on human skin with different mechanisms, providing a scientific rationale for their use.
Nowadays air pollution is a global environmental and health problem of growing concern. While some kinds of air pollution are produced naturally, anthropogenic activities are the main cause of the emission of chemical pollutants into the atmosphere. 
Most of air chemical pollutants of human origin are produced by the combustion of fossil fuel to produce heat and energy, major industrial processes, exhaust from transportation vehicles and agricultural sources. 
Air pollution is composed of a heterogeneous mixture of compounds, categorized into two broad groups: primary and secondary pollutants. Primary pollutants are emitted directly from pollution sources, and include gases, low molecular weight hydrocarbons, persistent organic pollutants, heavy metals  and particulate matter. 
Secondary pollutants are formed in the atmosphere through chemical and photochemical reactions involving primary pollutants; they include ozone, NO2, peroxy acetyl nitrate, hydrogen peroxide and aldehydes. Gaseous pollutants are mainly produced by fuel combustion, while dioxines are produced when materials containing chlorine are burned. 
Airborne particulate matter is a major concern especially in the air of densely populated urban areas; it consists of mixtures of particles of different size and composition. Depending on their aerodynamic diameter, they are commonly referred to as PM10, PM2.5–10, PM2.5  and ultrafine particles. The composition of PM varies, because they can absorb and carry on their surface a great variety of pollutants, such as gases, heavy metals, organic compounds, polyaromatic hydrocarbons, directly related to their toxicity. In countries such as Northern India and China, particularly high levels of PM2.5 are detectable subject to seasonal fluctuations and higher than the World Health Organization (WHO) recommendations.
Exposure to air pollution is associated with increasing morbidity and mortality worldwide. Airborne pollutants may penetrate the human body through multiple routes, including direct inhalation and ingestion, as well as dermal contact, and they cause well-documented acute and long-term effects on human health. 
Once inhaled, airborne pollutants can affect respiratory system, with airways irritation, bronchoconstriction and dyspnoea, lung inflammation and worsening of conditions of patients with lung diseases. 
Epidemiological and clinical studies have shown that air pollution is also associated with cardiovascular diseases, and a relationship of exposure to air pollutants with the risk of acute myocardial infarction, stroke, ischaemic heart disease and increase in blood pressure was reported. 
Moreover, there is increasing evidence that outdoor pollution may have a significant impact on central nervous system and may be associated with some neurological diseases, such as Alzheimer’s disease, Parkinson’s disease and neurodevelopmental disorders.
 Air pollution is also considered a risk factor in the incidence of some other pathological conditions, such as autism, retinopathy, low birth weight and immunological dysfunctions.
Being the largest organ of the human body as well as the boundary between the environment and the organism, the skin unsurprisingly is one of the major targets of air pollutants. 
Air pollution has considerable effects on the human skin, and it is generally accepted that every single pollutant has a different toxicological impact on it. Recently, many Authors reported potential explanations for outdoor air pollutants impact on skin damaging, focusing their interest especially on PM and ozone.
PM are essentially combustion particles formed by a core of elemental carbon coated with a variety of chemicals, such as metals, organic compounds, particularly polycyclic aromatic hydrocarbons (PAHs), nitrates and sulfates. 
PM induce in skin oxidative stress, producing reactive oxygen species (ROS) and causing the secretion of pro-inflammatory cytokines. As a consequence of the increased production of ROS, an increase of matrix metalloproteinases (MMPs) occurs, resulting in the degradation of mature dermal collagen, which contributes to skin aging. 
Coarse PM produce ROS essentially through transition metals (iron, copper, vanadium, chromium) absorbed on their surface, which are able to generate ROS (especially OH°) in the Fenton’s reaction, while smaller particles produce ROS due essentially to the presence of PAHs and quinones. 
Quinones are by-products of diesel fuel combustion, but can also be produced in the skin through biotransformation of PAHs by some enzymes. Li et al demonstrated that ultrafine particles had the highest ROS activity compared to coarse and fine particles. 
PAHs are highly lipophilic carbon compounds with two or more fused aromatic rings, emitted to the atmosphere primarily from the incomplete combustion of organic matter. 
PAHs absorbed on the surface of airborne PM can penetrate into intact skin and exert direct effects on epidermis cells, such as keratinocytes and melanocytes.
 PAHs are ligands for the aryl hydrocarbon receptor (AhR), a ubiquitous ligand-dependent cytosolic transcription factor.
 When AhR ligands engage the receptor, a conformational change occurs in it, which leads to its nuclear translocation and subsequent binding and activation of several genes, included genes encoding several phase I and II xenobiotic metabolizing enzymes. 
The oxidized products of PAHs metabolized by these enzymes induce oxidative stress responses in cells and confirm the involvement of PAHs in the genesis of skin damage due to air pollution. 
Pan et al explored the effect of PM on the function of skin barrier, and showed that particulate matter disrupt stratum corneum and tight junctions both in in vitro and in vivo experiments in pigs, also promoting the skin uptake of some drugs.
Ozone occurs in the stratosphere and in the troposphere, where it is present as a main component of photochemical smog. 
At ground-level it is normally found in low concentrations, but it can be formed in higher amounts through interaction of UV radiations with hydrocarbons, volatile organic compounds and nitrogen oxides, becoming a ubiquitous pollutant in the urban environment with concentrations ranging from 0.2 to 1.2 ppm.
 Due to its peculiar anatomical position, skin is one of the tissues more exposed to the detrimental effects of ozone, especially during smoggy and O3-alert days. 
Although Afaq et al. showed in human epidermal keratinocytes that AhR is an ozone sensor in human skin, suggesting that AhR signalling is an integral part of induction of cytochrome P450 isoforms by O3, ozone should not reach viable skin cells due to its high reactivity, and it is common opinion that its main cutaneous target is the stratum corneum.
 Ozone represents an important source of oxidative stress for skin; studies on animal models showed that ozone exposure leads to a progressive depletion of vitamin E and hydrophilic antioxidants and to malondialdehyde production in murine stratum corneum, inducing oxidative damage to lipids and leading to a perturbation of epidermal barrier function. 
A study performed on the skin of human volunteers showed that the ozone exposure significantly reduced vitamin E levels and increased lipid hydroperoxides in the stratum corneum, confirming that the effects of O3 are limited to the superficial layers of the human skin.
 In addition to increasing oxidative stress and decreasing of antioxidant skin defenses, ozone exposure is able to induce pro-inflammatory markers and increase the levels of heat shock proteins in mice skin. 
Inflammatory reactions in turn induce the production of ROS, thus triggering a vicious circle. 
Detrimental effects of O3 on skin can be enhanced by simultaneous exposure to UV radiation. 
The use of topical antioxidant mixtures has proven to be effective in preventing O3-induced oxidative damage both in human keratinocytes in culture  and in reconstructed human epidermis.
Air pollution, with other exogenous factors such as UV radiation and smoking, is definitely recognized as an important extrinsic skin-aging factor, whose pivotal mechanism is the formation of ROS and the subsequent oxidative stress, which can trigger further cellular responses.
 The skin is equipped with an elaborate antioxidant defense system including enzymatic and nonenzymatic, hydrophilic and lipophilic elements; however, when the extent of the oxidative stress exceeds skin’s antioxidant capacity, it leads to oxidative damage, premature skin aging and eventually skin cancer.
Until today, no standard protocol is available to objectively substantiate the “anti-pollution” claim, though several in vitro and in vivo tests have been proposed to this purpose. 
In vitro tests are based on the use of cell cultures or reconstituted skin models and evaluate several biomarkers after pollutants exposure. 
In vivo tests, performed on volunteers’ panels, include instrumental evaluation of skin parameters and the evaluation of the levels of oxidative stress and inflammatory markers after exposure to pollutant stressors.
 The availability of reliable and specific markers of airborne pollution upon skin would allow to evaluate and quantify the cutaneous impact of this phenomenon, as well as to assess the effectiveness of ingredients or finished products in counteracting detrimental effects of air pollutants.
 Recently, the oxidation of squalene has been recognized as a useful model. Squalene, a high-unsaturated triterpene produced by human sebaceous glands and present in sebum with an average concentration of 12%, is very prone to oxidation and is one of the main targets of oxidative stress induced by air pollution. 
Its peroxidized by-products are considered inflammatory mediators and are involved in comedogenesis, acne and wrinkles formation. 
Pham et al. established various protocols to evaluate the influence of different pollutants upon squalene oxidation by determining the amount of squalene oxides produced, and concluded that squalene oxidation is a reliable marker of pollution-induced skin damage.
Recently, a small number of studies investigated the cause-effect relationship between air pollution and skin quality. 
Vierk?tter et al. found a significant association between traffic-related airborne particles and extrinsic skin aging signs in a group of German women. 
In particular, an increase in soot and particles from traffic  were associated with 20% more pigment spots on forehead and cheeks. 
The influence of air pollutants on a number of skin parameters was evaluated in a clinical comparative study conducted on 96 subjects in Mexico City  and 93 subjects in Cuernavaca, considered a town preserved from urban pollution.
 In this comparative study, the Authors studied quantitative and qualitative modifications of a number of skin parameters. 
The results of this investigation demonstrated that moisturizing was significantly higher in Cuernavaca population; an increased level of sebum excretion rate, a lower level of vitamin E and squalene in sebum, and an increase of lactic acid and a higher erythematous index of the face of subjects were documented in Mexico City group.
 In the stratum corneum a higher level of carbonylated proteins, a lower level of IL 1α, a decrease of ATP concentration and a decrease of chymotrypsin like activity were detected. 
A clinical evaluation conducted by dermatologists on the same groups showed a general tendency of a higher incidence of skin problems  in Mexico City population compared to Cuernavaca population.
In addition to the effects on healthy skin, a number of studies have shown that outdoor air pollution is a relevant risk factor for the development of atopic dermatitis, a chronic inflammatory skin disease, and can also exacerbate this condition. As a consequence, the prevalence of atopic dermatitis in urban areas is significantly higher compared to that of rural areas.
The awareness of detrimental effects of environmental pollutants on skin has increased enormously in the most recent years not only within the scientific community but also among consumers.
 As a consequence, the anti-pollution trend, originated in Asia and subsequently spread to Western markets, is nowadays a rising trend in cosmetics and personal care industry worldwide, and cosmetic brands are unceasingly developing new concepts and new active ingredients to meet consumers’ demand. 
Several cosmetic strategies can be adopted to protect human skin against environmental pollution. 
The very first step in an effective cosmetic anti-pollution routine is a proper cleansing of the skin to remove chemicals deposited on it. Another way to defend the skin against environmental stressors is the isolation of the epidermis through the formation of a cohesive and non-occlusive film on its surface, preventing the direct contact with airborne pollutants; this physical barrier can be obtained through the use of film-forming ingredients, both synthetic (silicones, acrylic acid copolymers) and naturally derived (peptides and polysaccharides extracted from plants or obtained by fermentation processes). 
The third approach is the inclusion in anti-pollution formulations of antioxidants, in order to protect against free radical effects, or ingredients able to up-regulate the antioxidant defenses of the epidermis cells. 
Some cosmetic companies introduce in their anti-pollution cosmetics several ingredients with different complementary mechanisms of action, obtaining formulations designed to tackle as many pollutants as possible.
Most of the active anti-pollution ingredients present in formulations on the market are products of botanical origin. 
This reflects a more general trend in the today’s cosmetics and personal care industry. 
Indeed plants contain countless metabolites with potential cosmetic applications, which combine efficiency, reduced risk of irritation and allergies, reduced adverse effects and the possibility to refer on the labels of beauty products placed on the market to claims such as “organic”, “environmental sustainability” and “fair trade”; these claims are increasingly popular amongst the consumers due to the ever-increasing demand for more ethical, natural and “green” formulations.
The current review aims to present a selection of the most popular ingredients of botanical origin marketed by suppliers with the claim “anti-pollution”, and the scientific rationale behind their cosmetic applications.
 A number of commercially available anti-pollution cosmetic ingredients of botanical origin were retrieved by an electronic survey conducted by the popular search engine Google and the technical websites for chemicals and materials Prospector, SpecialChem and Cosmetic Design Europe, using the key words “anti-pollution cosmetics” and “anti-pollution ingredients”.
 For practical reasons, it has been decided to include in this review only the ingredients derived from a single botanical species, thus excluding the products containing mixtures of plant extracts.
 For each ingredient the technical documentation was acquired from the manufacturers’ own websites. 
Subsequently, scientific papers, found by using the academic search engines Google Scholar, ScienceDirect and PubMed, were consulted to verify the scientific soundness of the anti-pollution claims of these botanical extracts plants.
 For the ease of the readers, the anti-pollution ingredients taken into account in this review were divided into two tables, according to their botanical origin: Algae and Spermatophytae. 
In these tables, the trade name, the supplier, the INCI name, the supplier claims and the recommended concentrations were reported for each ingredient.
Marine algae are eukaryotic organisms classified in microalgae and macroalgae. Macroalgae  are in turn classified in Rhodophyceae, Chlorophyceae  and Pheophyceae, according to their dominant pigment. 
Algae provide a great variety of metabolites and can be easily cultured on seashores in great volumes; moreover, they grow quickly, and it is possible to control the production of their metabolites by manipulating the culture conditions. 
For all these reasons, algae represent an attractive renewable source of bioactive compounds with potential applications in pharmaceutical, nutraceutical and cosmetics industries.
A number of bioactive compounds and extracts derived from macroalgae have proven to be useful in the treatment of some skin conditions.
 Some algae species produce bioactive molecules with photo-protective activity due to their ability to absorb UV-A and UV-B radiation; other algal species are potential sources of skin whitening agents, since they produce metabolites able to inhibit natural tyrosinase. 
Moreover, some compounds derived from algae exhibit antibacterial and anti-inflammatory activity and can be useful in the management of acne-affected skin. Other bioactivities from algae are closely linked to the use of seaweed-derived products as anti-pollution cosmetic ingredients.
 In particular, researchers have extensively investigated the antioxidant activity of algae extracts; indeed algae, due to the extreme conditions in which they often live, are naturally exposed to oxidative stress, and develop efficient strategies to protect against the effects of ROS and other oxidizing agents.
 The antioxidant potential of a variety of algal species extracts was demonstrated with different methods, such as 2,2-diphenyl-1-picrylhydrazyl free-radical-scavenging, ferric-reducing antioxidant power, ABTS  radical scavenging, in vitro copper-induced oxidation of human LDL  assay, reducing activity, metal chelating assay, scavenging ability on hydroxyl and superoxide radicals.
 Brown algae have been reported to contain comparatively higher contents and more active antioxidants than red and green algae.
 A statistically significant correlation between this antioxidant activity and the total polyphenol content of these extracts was demonstrated, suggesting that this class of compounds is at least in part responsible for the antioxidant properties of seaweed extracts.
 Amongst the many polyphenols been identified in algal extracts, of particular interest are phlorotannins, formed by polymerization of phloroglucinol units linked together in different ways.
 Phlorotannins only exist within brown algae, are not found in terrestrial plants, and can be divided into six categories.
They possess a strong antioxidant activity related to phenol rings in their structure, and having up to eight rings they are more efficient free radical scavengers when compared to polyphenols from terrestrial plants, which have 3–4 rings.
Other components which contribute to the antioxidant potential of algae are sulfated polysaccharides, that in recent times have attracted the interest from life science researchers owing to a wide range of biological activities with potential health benefits, such as anti-allergic, anti-HIV, anticancer, anticoagulant and anti-oxidant activities.
 Sulfated polysaccharides are anionic polymers widespread among marine algae but also occurring in animals; their chemical structure varies depending on the seaweed species that they come from.
 The most important sulfated polysaccharides recovered in marine algae are ulvans in green algae, carrageenans in red algae and fucoidans and laminarians in brown algae.
Ulvans are water-soluble sulfated heteropolysaccharides, mainly constituted by disaccharide repeated units formed by d-glucuronic or l-iduronic acid linked to l-rhamnose-3-sulfate.
 These polymers exhibit a broad range of biological activities, a notable example being the antioxidant one. 
The antioxidant properties of ulvans are influenced by the extraction procedures and depend on the carbohydrate composition and the sulfate content, since ulvans with higher sulfate content show a significantly higher antioxidant activity.
The composition, structures and biological properties of fucoidans have been extensively reviewed. They are sulfated polysaccharides found exclusively in the cell walls of brown algae; their major components are l-fucose and sulfate. 
Fucoidans exhibit a broad spectrum of biological activities, including anticancer, apoptosis-inducing, immunomodulatory, antiviral, anti-thrombotic, anti-inflammatory and antioxidant activities. 
In vitro antioxidant activity of fucoidans has been determined by various methods, such as DPPH free radical scavenging assay, iron-chelating activity assessment, superoxide anion and hydroxyl radical scavenging activity, reducing power assay. 
Recently, effective methods of extraction of fucoidans, alternative to classical extraction methods, time-expensive and associated to multi-step processes, high temperature, large solvent volumes, were developed. 
Fucoidans extracted by these techniques exhibited in some cases a higher antioxidant activity than those extracted by conventional methods. 
In addition to their antioxidant properties, fucoidans possess another biological activity relevant in the cosmetic field: they are able to prevent UVB-induced matrix metalloproteinase-1 (MMP-1) expression and suppress MMP-3 in vitro. 
MMPs induce degradation of dermal proteins such as collagen, fibronectin and elastin, contributing to skin damage; therefore fucoidan may be useful to prevent skin photoaging not only by scavenging ROS formed during exposition to UV radiations, but also by inhibiting the formation of MMPs.
As shown in Table S1, a number of cosmetic ingredients based on algal extracts have been developed and are proposed by manufacturers as functional substances suitable for anti-pollution skincare products. Their use is substantiated not only by the general literature referred so far, but often also, when available, by investigations focused on specific algal species.
The ingredient No. 1, Contacticel?, contains an extract of Acrochaetium moniliforme, an epiphytic red macroalga made of cell filaments found in very low quantities in the ocean; the patented Celebrity? technology produces biomass of this red alga in photobioreactors in a sufficient quantity, unavailable in the sea. 
Scientific literature on possible biological activities of this alga was not found; the information leaflet of the manufacturer claims that the patented commercial extract limits in vivo excessive sebum production and reduces the ozonolyzed squalene (tests performed versus placebo on two groups of 20 women each, in Shanghai’s polluted atmosphere). 
Moreover, in an in vitro sebocyte model exposed to urban dust the extract proved to be effective in regulating the lipid production.
The antioxidant activity of the edible brown seaweed Laminaria digitata  is documented by a number of investigations. The study of Heffernan et al. showed that the crude extracts of L. digitata showed a total phenolic content and an antioxidant activity lower than other macroalgae examined, but these parameters improved when the extracts were fractionated with suitable dialysis membranes. Moreover, it has been demonstrated that the thermal treatment increased its content in antioxidant compounds and improved its free radical scavenging activity.
The ingredients No. 3 and No. 7 contain as an active anti-pollution ingredient Undaria pinnatifida extract; this brown alga is widely used as food and as a remedy in traditional Chinese medicine for over 1000 years. 
As stated previously for brown algae, U. pinnatifida contains sulfated polysaccharides that exhibit good antioxidant activities, related with their sulfate content. 
Moreover, it also contains fucoxanthin, a carotenoid present in the chloroplasts, able to counteract oxidative stress by UV radiation.
The ingredient No. 4, designed to be used in hair-care products, contains a hydroglycolic extract of the brown seaweed Pelvetia canaliculata. 
Although P. canaliculata, like all brown algae, contains fucoidans  and phlorotannins and carotenoids, able to absorb UV radiation and to fight photoxidative stress, the leaflet supplied by the manufacturer emphasises the effectiveness of its extract in reducing residues and depositions caused by the action of pollutants, chlorine and the build-up effect of cationic hair conditioners. 
Alginates and fucoidans contained in the cells walls of P. canaliculata are poly-anions due to the presence of carboxylic and sulfonic groups, and as a consequence this alga can act as a natural cation exchanger. 
This ability is widely documented in the scientific literature, and it was proposed to use P. canaliculata biomass to sequestrate and remove metal ions (zinc, iron, copper, trivalent chromium, lead, nickel) from industrial wastewaters.
 All of these biological activities make P. canaliculata extract a good candidate for the formulation of anti-pollution cosmetics.
The ingredient No. 5 consist of an extract of Ascophyllum nodosum, harvested on Ouessant Island by a hand cutting harvest method; it is concentrated in high molecular weight fucoidans, as declared by manufacturer.
 The antioxidant activity of this brown seaweed is well documented and can be attributed to the presence of both sulfated polysaccharides and phenolic compounds. A. nodosum contains the abovementioned fucoidan but also ascophyllan, another sulfated polysaccharide structurally similar to fucoidan characterized by a more pronounced antioxidant activity, in addition to a wide variety of interesting biological activities.
 Moreover, A. nodosum produces a variety of phenolic compounds, namely phlorotannins, flavonoids and phenolic acid derivatives. 
On the leaflet of the manufacturer the extract No. 5, at the concentration of 3%, is claimed to decrease AhR receptor expression by 73% compared to a placebo in an ex vivo test. 
Moreover, to this ingredient is ascribed the ability to reinforce the skin barrier; in particular, it is reported that on the model of reconstructed epidermal skin Episkin? native fucoidans (5%) increased the number of mature corneocytes by 225%, while the whole extract (3%), after 56 days, decreased TEWL, an indicator of the barrier dysfunction, by 13% versus placebo in an in vivo test.
Finally, the ingredient No. 6 contains an extract of the green alga Ulva lactuca, also known by the common name of sea lettuce and rich in the sulfated polysaccharides ulvans, as mentioned above. 
If administered orally, U. lactuca extracts show anti-inflammatory effect in carrageenan-induced paw oedema in rats and are able to ameliorate hepatic enzymatic and non-enzymatic antioxidant defenses of hypercholesterolemic rats.
Eriodictyon californicum is an evergreen shrub within the Boraginaceae family, native to Central America. 
For centuries Native Americans used it as a medicinal plant to treat several respiratory conditions and skin wounds. 
The leaves of E. californicum are covered by a resin containing flavonoids (such as eriodictyol and homoeriodictyol), which act as herbivore deterrents and UV screens; this plant is also a source of moisturizing compounds such as mucopolysaccharides and glycoproteins, which produce their moisturizing effects via hydrogen bonding of water by their sugar moieties.
In the technical data sheet provided by the manufacturer a remarkable improvement of skin moisturization (30%) produced by Yerba Santa Glycoprotein PF (5%) was reported, whereas in the same experimental conditions Aloe vera gel 10× produced an increase of 20%. Ingredient No. 1 was also tested to verify its anti-pollution properties.
 The extract was applied to the skin, which was then contaminated with a known amount of activated charcoal. 
After washing with a controlled volume of water, the amount of microparticles remained on the skin was evaluated; when compared with an untreated control, the extract was able to prevent the deposition of PM particles into the skin fine lines and wrinkles. 
The extracts of E. californicum, due to the presence of flavonoids such as homoeriodictyol and eriodictyol, well known for their antioxidant activity, provide further benefits when added to cosmetic formulations.
The ingredient No. 2 of Table S2 is composed by polyphenols extracted from green tea leaves and esterified with palmitic acid.
 Green tea is obtained by roasting or steaming Camellia sinensis (Theaceae) leaves in order to inactivate polyphenol oxidase activity.
 Green tea extracts are complex mixtures of bioactive compounds, including tea polyphenols, primarily green tea catechins, that account for 30–40% of the extractable solid of dried green tea leaves. Tea catechins include epicatechin, epicatechin-3-gallate, epigallocatechin and epigallocatechin gallate. 
These polyphenols have gained interest in recent years because of interesting biological activities, including antimicrobial, anti-inflammatory, anticancer, antioxidant and radical scavenging activities. 
On the basis of their biological properties, green tea polyphenols are generally accepted as having a protective effect against oxidative stress and DNA and cell structures damage induced by a number of environmental toxins/toxicants; these properties provide the rationale for the use of green tea extracts as functional ingredients of anti-pollution cosmetics.
However, it is known that polyphenols in their native form are unstable because they are susceptible to oxidation induced by several environmental agents. 
Moreover, green tea polyphenols are soluble in water and therefore difficult to use in cosmetic formulations when lipophilic ingredients are required. 
A way of stabilizing these polyphenols and imparting them lipophilic properties is protecting the phenol functions as fatty acid esters with a method described in the American Patent US 5808119. 
To evaluate whether the biological properties of polyphenols are maintained after esterification, studies were performed by using cutaneous explants from abdominoplasty surgery as a model of human skin. 
After topical application of the green tea extract, free radical production was induced by UV radiation; the lipid peroxidation process was studied by determining the levels of malonyldialdehyde (MDA) as indicator. 
Stabilized polyphenols showed a good anti-lipoperoxidant activity, higher than that of Vitamin E. Since the radical scavenging of polyphenols related is to the free phenolic OH, it is assumed that esterified polyphenols permeate the skin barrier and then are hydrolyzed by skin esterases to the active forms. 
Moreover, green tea polyphenols at concentration of 0.1% and 0.25% respectively induce an increase of 18% and 40% of collagen IV in the dermo-epidermal junction; at 0.25% and 0.5% they increase of 13% and 21% fibriline-1 in the dermo-epidermal junction.
Marrubium vulgare is a plant widely used in antipollution skincare products; four ingredients examined in this review (ingredients No. 4, 6, 7 and 8, Table S2) contain M. vulgare extracts.
 The genus Marrubium includes about 40 species of flowering plants indigenous in Europe, Mediterranean area and Asia.
 Many species of Marrubium are reported in the literature to be used in folk medicine and their extracts have been investigated for their chemical composition and for their antioxidant and lightening properties. 
M. vulgare, widely used in traditional medicine in some countries, is the most investigated species of Marrubium.
 Its aerial parts are official in Hungarian Pharmacopoeia VII, and the European Medicine Agency (EMA) approved in 2013 the treatment of cough associated to cold, mild dyspeptic complaints and temporary loss of appetite as indication for aerial part of this plant. 
M. vulgare is reported to possess several biological activities, among which the most interesting are antihepatotoxic, antihyperglicemic, antibacterial, anti-inflammatory  and antioxidant properties. 
In particular antioxidant properties may justify the widespread of Marrubium vulgare extracts, often prepared with peculiar extraction techniques, as natural cosmetic ingredients, with claims including anti-pollution, antioxidant, protective for irritated and stressed skin, detoxifying, soothing. 
Reported results suggest a remarkable antioxidant activity of M. vulgare extracts assessed with different methods (DPPH° radical scavenging, scavenging activity against hydrogen peroxide, iron reducing power). 
In order to correlate this antioxidant activity to specific bioactive compounds, phytochemical composition of M. vulgare has been extensively investigated; these studies, conducted on different types of extracts, led to the identification of a wide array of phytochemical compounds, such as flavonoids, terpenoids and phenylethanoid glycosides. 
Several flavonoids were isolated from M. vulgare, including luteolin, apigenin, terniflorin, anisofolin A, ladanein. Phytochemical screening revealed the presence of several terpenoid compounds, such as marrubiin, premarrubiin, marrubenol, sacranoside A, deacetylforskolin, preleosibirin, marrulibacetal. 
Finally, several phenylpropanoid compounds were isolated and identified from M. vulgare: caffeoyl-l-malic acid, verbascoside, decaffeoylverbascoside, forsytoside B, alyssonoside, leukoceptoside A, acteoside, arenarioside, ballotetroside. Ladanein, verbascoside and forsythoside B showed a relevant antioxidant activity in vitro; on the other hand, experimental data suggest that natural phenylpropanoids could protect cells from oxidative stress. 
These studies justify the use of M. vulgare extracts as cosmetic ingredient and support scientific substantiation of the anti-pollution claim.
Schinus molle (Anacardiaceae), also known as Peruvian pepper tree, false pepper or pink pepper, is an evergreen tree native to Peruvian Andes. 
Widely used in traditional medicine for its purported analgesic, antidepressant, antimicrobial, diuretic, astringent and antispasmodic properties, Schinus molle exhibits insect repellent, anti-inflammatory, antifungal and antioxidant effects.
 The antioxidant properties of leaf and fruit essentials oils of S. molle were demonstrated by using DPPH° free radical, ABTS and β-carotene/linoleic acid method. 
Methanolic extracts of bark and flowers of S. molle were also tested for their DPPH° scavenging activity, and they exhibited a remarkable antioxidant activity when compared to quercetin. 
In aqueous methanolic extracts of the leaves of S. molle a number of polyphenolic metabolites were found, including glycosides based on quercetin as an aglycone.
 Some of them exhibited moderate to strong radical scavenging properties on lipid peroxidation, OH° and superoxide anion generation; the most active compounds were miquelianin and quercetin 3-O-β-d-galacturonopyranoside. An extract of Schinus molle is marketed as a cosmetic ingredient with anti-pollution, anti-aging and anti-wrinkle benefits. 
In the technical datasheet provided by the manufacturer it is stated that Elixiance? is rich in polyphenols such as quercitrin and miquelianin. 
As far as the anti-pollution benefits of this extract are concerned, the document claims that it “...limits the effects of air pollution in vitro, “…contributes to reduction in skin permeability induced by environmental stress (in vitro)…” and “…is associated with anti-pollution benefits supported by a clinical study on 39 volunteers in Shangai.” 
Moreover, a skin-purifying effect, characterized by a reduced quantity of skin sebum and by a decrease of the appearance of pores, is associated to S. molle extract.
Camellia japonica, also known as Rose of winter, is a flowering tree or shrub belonging to the Theaceae family and naturally occurring in China, Japan and Korea. 
An extract of C. japonica flowers is the active component of the ingredient No. 9 of Table S2 (RedSnow?). 
It has been reported that C. japonica, whose flowers and flower buds were traditionally used in oriental medicine as an astringent, anti-hemorrhagic and anti-inflammatory remedy, exhibits a variety of biological activities, such as antiviral, anti-atherogenic, anti-hyperuricemic, anti-photoaging, antioxidant, radical scavenging and anti-inflammatory effects, and glycation inhibitory action. 
The ethanol extract of C. japonica flowers exhibits antioxidant properties by scavenging ROS (superoxide and hydroxyl radicals) in a free-cell system and in human HaCaT keratinocytes; moreover, it is able to increase the protein expression of the antioxidant enzymes superoxide dismutase, catalase and glutathione peroxidase.
 The ROS scavenging effect and the induction of antioxidant enzymes of C. japonica extract may be associated with the presence of antioxidant phenolic compounds such as quercetin and kaempferol glycosides. 
In a study on the anti-aging properties of C. japonica flower extract in an ex vivo model, it has been shown that it reduces piknotic nuclei and it prevents the detachment of the dermo-epidermal junction induced by pollutants such as heavy metals and hydrocarbons; moreover, it also induces an increase of collagen I and a decrease of MMP-1. These results support the use of C. japonica flower extract in anti-aging and anti-pollution cosmetics.
Schisandra chinensis Baill is a plant native to China, Japan and Russia; its dried fruits are used in traditional Chinese medicine, where it is considered one of the 50 fundamental herbs. 
Modern studies show that this plant possesses several biological activities such as anti-hepatotoxic, antitumour, anti-inflammatory and antioxidant. 
The major constituents of the fruit extract of S. chinensis are lignans, a large group of naturally occurring phenols classified into several group according to their chemical structure. 
The fruit extract of S. chinensis especially contains lignans with dibenzocyclooctadiene skeleton, such as schisandrol, schisantherin A, deoxyschisandrin, schisandrin B and schisandrin C, and with tetrahydrofuran structure, such as d-epigalbacin, machilin G and chicanine; several scientific studies demonstrated the antioxidant activity of these compounds.
 Some recent studies have also shown the presence in fruits and leaves of S. chinensis of phenolic compounds with good antioxidant activity, such as chlorogenic acid, isoquercitrin and quercitrin. 
Schisandrin also exhibits anti-inflammatory activity, and S. chinensis fruit extract has been reported to reduce pro-inflammatory cytokine levels in THP-1 cells stimulated with P. acnes and to protect UVB-exposed fibroblasts from photoaging.
 Due to these biological properties, the extract from S. chinensis fruits has beneficial effects on the skin, and has been proposed as a cosmetic anti-pollution ingredient.
This ingredient contains schisandrin 8–12%.
 In the datasheet provided by the manufacturer it is claimed that this product is able to reduce the NQ01 (NAD(P)H dehydrogenase 1) expression, to limit the expression of MT1H (Metallothionein 1H) and to protect from inflammation on a 3D reconstructed full-thickness skin model exposed to a mixture of urban pollutants (in vitro tests); in vivo tests performed on female volunteers exposed to urban pollution showed a conservation of basal TEWL, an amelioration of skin radiance and an improvement of microcirculation and tissular oxygenation.
Several scientific investigations have established that the prolonged exposure to environmental pollutants can produce in human skin biochemical parameters modifications and impairment of barrier function, and can promote the mechanisms of skin aging; the visible results of these effects are dryness, wrinkles, dark spots, sagging and the aggravation of skin sensitivity. 
As the awareness of the impact of environmental stressors on the skin grows, there is an increasing consumer demand for cosmetics and personal care products able to provide anti-pollution benefits.
 The anti-pollution skincare is one of the latest cosmetic trends; started in Asia, it is currently gaining ground all over the world, and new solutions, ingredients and products specifically designed to offer skin protection against pollution are continuously developed.
 With the growth in demand for natural cosmetics steadily on the rise, it is natural that plant extracts are becoming the most popular ingredients of cosmetics designed to fight skin pollution; indeed plant extracts are often rich in bioactive compounds whose activities can be exploited in anti-pollution formulations.
 As stated above, airborne pollutants induce adverse effects on human skin mainly via oxidative damage, with a consequent oxidative stress and a depletion of ant ioxidant enzymes and other antioxidant substances in epidermis.
 For this reason, it is not surprising that most of the plants used as a source of anti-pollution cosmetic ingredients contain antioxidants as active substances.
This review was aimed to give a representative list of the most popular anti-pollution cosmetic ingredients of botanical origin, describe their mechanism(s) of action and provide a scientific rationale justifying their use.
 This list is not exhaustive; indeed, manufacturers are expected to propose an increasing number of plant derivatives as active ingredients of antipollution cosmetics, since the demand for this skincare segment is here to stay and it will even increase.
Consumers pay more and more attention not just to the safety and health aspects of ingredients entering their cosmetics’ formulations, but also to their potency, origin, processing, ethical value and environmental footprint.
Sustainability of the supply chain, preservation of biodiversity, as well as greener extraction techniques are hence very popular with consumers.
Consumers are primarily concerned by the efficacy of the cosmetic products they use and continuously scrutinize product labels, so marketing arguments need to be based on rigorous testing and reliable results to support claims displayed on the product’s packaging.
As a result, the increasing demand for natural ingredients with assessed bioactivities has profoundly modified the strategies adopted by cosmetic professionals to innovate in terms of actives. 
Sourcing and developing new natural cosmetic actives is a long-term procedure that is thoroughly described in the present paper, via the example of the design of both liquid and solid ingredients based on Quercus pubescens Willd. leaves extract, for which anti-age properties were assessed by a combination of in vitro assays.
Constantly evolving consumers’ lifestyle is the key driver behind the transformation of the worldwide cosmetic industry engaged over the two past decades. 
The sector is expected to reach $429.8 billion by 2022, registering a CAGR of 4.3%.
 An inclination towards natural beauty and personal care products has been initiated few years ago, fueled by the consumers’ ecological and ethical considerations, and their will for safer cosmetics.
‘Natural’ is often, not always quite rightly, synonym of ‘safer products presenting less side effects’ in the consumers’ mind and one notably notices the boom of ‘without’ claims.
 In brief, consumers are looking for safer and greener cosmetic ingredients and place a premium on real efficacy, so manufacturers must provide tangible evidence of the allegations claimed on the products’ packaging.
 Consequently, manufacturers are constantly seeking originality and naturality, while multiplying bioassays to scientifically substantiate cosmetic allegations, and the natural beauty market valued approximately 11.06 billion U.S. dollars worldwide in 2016, is estimated to reach almost 22 billion U.S. dollars in 2024.
The global cosmetic ingredients market amounted to approximately 22.9 billion U.S. dollars in 2016 is expected to rise to reach 33.80 billion U.S. dollars by the end of 2025.
 Even continuously progressing, natural ingredients still represent today only 7% of the global market. 
To keep up with current trends, cosmetic manufacturers must ceaselessly innovate and develop new natural ingredients in accordance to consumer preferences, using the latest technologies of extraction, and notably of eco-extraction, or exploring the potentialities of original natural resources, while keeping sustainability and ethics in mind. 
Manufacturers can adopt one of the two following strategies to source naturally derived ingredients: they can either call on ethnobotanical knowledge, i.e., select plants of interest based on their renown traditional use, or based on a high-throughput screening.
Consumers are daily exposed to air pollutants and to all kinds of blue light sources. 
They are more and more concerned with the impact of pollution and their hectic lifestyle, on the quality and beauty of their skin. 
These preoccupations are strongly setting the guidelines of the cosmetics market over the next few years: anti-pollution, anti-blue light and moreover anti-age actives will call the tune on the cosmetic ingredients’ market. 
Skin health and beauty are intimately linked to the overall consumers’ well-being, so it is not surprising that skincare constitutes the cosmetic segment that witnessed the strongest growth over the 1998–2010 period, with maket shares evolving from 16.4% to 23.0%. 
Skin aging is a complex biological process influenced by a combination of endogenous  and exogenous  factors. To fight the visible signs of aging, cosmetic anti-aging ingredients reinforce the skin barrier, improve the skin elasticity, boost its density, protect it against radicals, fade wrinkles, diminish the apparition of age spots, etc. 
The pursuit of beauty and the demographic realities—life expectancy registered over the last few years its fastest gain since the 1960s—are substantially and ceaselessly fueling the demand for anti-aging actives and formulations; this sector is no exception: naturality rules.
The worldwide biodiversity constitutes an exceptional reservoir of innovative molecules presenting highly diverse structures and functions that can be tapped for novel drug leads as well as cosmetic development.
 The Mediterranean area has long been identified as a region presenting high biodiversity due to its remarkable flora and specially its high rate of endemic species: representing only 2% of the world’s surface, this area houses 20% of the world’s total floristic richness. 
This Mediterranean biome hence constitutes a choice target to source interesting molecules and notably natural ingredients intended for cosmetics and personal care formulation. 
Due to its establishment at the heart of this rich region and to its expertise in phytochemistry, our research team has access to this diversity through longstanding collaborations. 
Hence, 50 Mediterranean plants were initially selected over more than 500 available at the laboratory for the present study, based on their accessibility and their originality regarding the anti-aging activity. 
Hence, aqueous and organic solvent extracts, as well as essential oils were investigated for their anti-aging properties. From this survey, a crude extract of Quercus pubescens Willd. 
Leaves display the best unprecedented anti-aging activities and was then selected for further investigations leading to the development of an innovative anti-age active and its practical cosmetic formulation.
Q. pubescens, commonly known as downy or pubescent oak, is a species of white oak native to southern Europe and southwest Asia; the word ‘pubescens’ meaning ‘with soft bristle’ actually refers to its hairy leaves and twigs, constituting an adaptation to drought.
 This species is also known as ‘truffle oak’ as it serves among other species as a host for economically important truffles. Q. pubescens is a medium-sized deciduous tree growing up to 20 m, preferentially in regions presenting a sub-Mediterranean microclimate characterized by hot dry summers and cool winters with little rainfall. 
Particularly adaptable, this species grows on well-drained lime soils as well as on acidic grounds, and is found from sea level up to 1300 m.
 Extracts of various species of oak are already used in cosmetics, mainly as skin conditioning actives; however, those actives are mainly based on bark or wood extracts: such a sampling endangers the survival of the oak trees tapped and is therefore not sustainable.
 One patent reports the composition of an anti-oxidant cosmetic formula based on Q. robur, Q. ilex and Q. pubescens bark extracts. 
To our knowledge, no previous study reports the development and the subsequent use of an extract of Q. pubescens leaves as a cosmetic active.
Developing and objectifying new natural cosmetic ingredients is a long-term procedure that is presented in detail in this article, via the example of the design of an anti-age ingredient based on an extract of Q. pubescens leaves.
 The first step consists of the optimization of the extraction procedure of Q. pubescens leaves to potentialize the bioactivity of the resulting extract while keeping in mind its further industrial scale-up.
 The second part of such a development encompasses the amelioration of the extract’s formulability, including its discoloration and/or deodorization, and the further development of both liquid and solid forms of the cosmetic ingredient.
The plant material was air dried and crushed into fine powder. 
Extraction of plant material was then performed by maceration using either the water/ethanol system or pure EtOH. About 1 g of plant material was extracted with approximately 10 g of solvent (extraction ratio 1/10) at room temperature (RT) using a magnetic stirrer (500 rpm) for 2 h.
 The resulting extracts were then filtered over filter paper 8–12 ?m, gathered together and vacuum-concentrated to dryness.
To identify the active fractions, the H2O/EtOH 1/1 extract of Q. pubescens leaves was then fractionated over silica gel.
 The fractionation of the bulk extract led to the recovery of 5 distinct fractions: F1 (250 mL cyclohexane), F2 (250 mL cyclohexane/diethyl ether 1/1), F3 (250 mL diethyl ether), F4 (250 mL methanol) and F5 (250 mL methanol/water 1/1). 
The resulting fractions were further evaluated for their bioactivities, and their respective compositions were addressed by HPLC and GC, as well as by UPLC-HRMS 
Crude extracts and fractions diluted at 10 mg/mL in methanol and filtrated over 0.45 ?m PTFE syringe filter, were analyzed using an HPLC Agilent 1200 system  equipped with a DAD and an ELSD  operating under the following conditions: injection volume: 20 ?L, and flow rate: 1.0 mL/min. 
Separations were performed on a C18 column (Phenomenex, Le Pecq, Ile-de-France, France; Luna? 5 μm, 150 mm × 4.6 mm i.d.).
 The mobile phase consisted in a multistep gradient of water (A), acetonitrile (B) and 2-propanol (C), all acidified with 0.1% acid formic: 0–5 min, 5% B; 5–40 min, 5–45% B; 40–50 min, 100% B; 50–55 min, 100% B; 55–68 min, 100% C, 68–70 min, 100% C. 
The DAD was set at 220, 254 and 330 nm, and ELSD conditions were set as follows: nebulizer gas pressure 3.7 bars, evaporative tube temperature 40 °C and gain 4.
Q. pubescens extract obtained using H2O/EtOH 1/1 was then evaporated to dryness, dissolved in methanol (50 mg/mL) and semi-preparative HPLC was performed on a C18 column (Phenomenex, Le Pecq, Ile-de-France, France; Luna? 5 μm, 250 mm × 10 mm i.d.).
 Elution was performed using a multistep gradient of water (A) and acetonitrile (B), both acidified with 0.1% acid formic: 0–5 min, 5% B; 5–10 min, 5–100% B and 10–14 min, 100% B, under the following conditions: injection volume: 100 ?L, and flow rate: 4.0 mL/min. 
Multiple injections were carried out and the resulting respective sub-fractions were pooled together.
he GC-MS analyses were performed using an Agilent 6890 gas chromatograph (Palo Alto, CA, USA) equipped with an Agilent MSD5973N mass selective detector, a multifunction automatic sampler (Combi-Pal, CTC Analytics, Zwingen, Switzerland) on an HP-1 MS capillary column (100% polydimethylpolysiloxane; 0.2 mm × 50 mm; film thickness, 0.33 μm).
 Samples (1 ?L) were injected in splitless mode (split vent: 50 mL/min–30 s) and the injector was set at a temperature of 250 °C. 
The carrier gas was helium in constant flow mode at 1 mL/min.
 The oven temperature was programmed to rise from 60 °C to 180 °C at 2 °C/min, then from 180 °C to 300 °C at 6 °C/min and kept isothermally at 300 °C for 5 min. 
Acquisition was performed in scan mode (35–500 a.m.u. (atomic mass unit)/s; scan rate: 3.15 scans/s) and mass spectra were generated at 70 eV.
Compound identifications were based on comparison of mass spectra with literature, commercial libraries NIST, Wiley, Indianapolis, IN, USA) and laboratory MS libraries built up from pure substances, combined with comparison of GC linear retention index.
 Retention indices were determined with a series of linear alkanes C8–C24 used as a reference.
Untreated 96-well plates were purchased from Thermo Nunc, whereas the UV-transparent ones were obtained from Costar, Sigma-Aldrich. Adhesive films were used to seal the 96-well plates during incubation. 
Samples were prepared at a concentration of 3.433 mg/mL in dimethyl sulfoxide (DMSO) in 1.5 mL Eppendorf tubes, appropriate for the use of the automated pipetting system epMotion? 5075.
An hydroglycerinated extract of Q. robur heartwood commercialized for its claimed protective activities against photo-aging, free radicals and environmental factors, was tested alongside our samples to perform direct comparison between oak-based ingredients.
An automated pipetting system Eppendorf epMotion? 5075 was used to carry out the bioassays.
 A microplate reader (Spectramax Plus 384, Molecular Devices, Wokingham, Berkshire, UK) was used to measure absorbance values.
 Data were acquired with the SoftMaxPro software (Molecular devices, Wokingham, Berkshire, UK) and the Prism software (GraphPad Software, La Jolla, CA, USA) was used to calculate inhibition percentages.
Similarly, all OD were corrected with the blank measurement corresponding to the absorbance of the sample before addition of the substrate.
The antioxidant activity of the extracts and fractions was measured based on the scavenging activity of the stable 1,1-diphenyl-2-picrylhydrazyl radical according to the following method widely used to examine the antioxidant activity of plant extracts: 150 ?L of a solution of ethanol/acetate buffer 0.1 M pH = 5.4 (50/50) were distributed in each well, together with 7.5 ?L of the extracts evaluated. 
Trolox (3607.8 ?M in DMSO) and a commercial extract of Rosmarinus officinalis L. (3.433 mg/mL in DMSO) were used as positive controls; DMSO alone constitutes the negative one (ODcontrol). 
A first OD reading was performed at 517 nm.
 Then, 100 ?L of a DPPH solution were distributed in each well. The plate was sealed and incubated in the dark at room temperature (RT). After 30 min, the final OD reading was performed at 517 nm to assess the percentage of inhibition.
Tyrosinase is a copper-containing oxidase controlling the production of melanin; it is mainly involved in the hydroxylation of l-tyrosine into L-DOPA and its further oxidation to dopaquinone.
 Since this enzyme plays a key role in melanogenesis, tyrosinase inhibitors are of great concern in the development of skin whitening agents.
 The assays were performed as follows: 150 ?L of a solution of mushroom tyrosinase prepared at a concentration of 171.66 U/mL in phosphate buffer were distributed in each well or 50 U/mL, together with 7.5 ?L of the extracts evaluated. 
Kojic acid (3.433 mM in DMSO) and a commercial extract of Arctostaphylos uva-ursi (L.) Spreng. (3.433 mg/mL in DMSO) were used as positive controls; DMSO alone constitutes the negative one (ODcontrol).
 The plate was filmed and incubated at RT for 20 min. 
Then, 100 ?L of a solution of l-tyrosine (monophenolic activity assay) or L-DOPA (diphenolic activity assay) 1 mM in phosphate buffer pH = 6.8 (substrate’s final concentration per well: 0.388 mM) were distributed in each well. After 20 min of incubation, OD reading was performed at 480 nm to assess the percentage of inhibition.
Lipoxygenase, an iron-containing enzyme catalyzing the deoxygenation of polyunsaturated fatty acids into the corresponding hydroperoxides, is known to play a key role in inflammation [34]. The assays are performed as follows: 150 ?L of a solution of soybean lipoxygenase prepared at a concentration of 686.66 U/mL in phosphate buffer (50 mM pH = 8) were distributed in each well, together with 7.5 ?L of the extracts evaluated.
 Quercetin hydrate (1000 ?M in DMSO) and a commercial extract of Arnica montana L. (3.433 mg/mL in DMSO) were used as positive controls; DMSO alone constitutes the negative one (ODcontrol).
 The plate was sealed and was incubated in the dark for 10 min. Then, 100 ?L of a solution of linoleic acid prepared in phosphate buffer pH = 8 were distributed in each well. 
After incubation for 2 min in the dark, a first OD reading was performed at 235 nm. After a further incubation of 50 min, the final OD reading was performed at 235 nm to assess the percentage of inhibition.
Elastase is a serine protease that preferentially digests elastin, the highly elastic protein that works together with collagen to give skin its shape and firmness.
 The assays were performed as follows: 150 ?L of a solution of porcine pancreatic elastase prepared at a concentration of 0.171 U/mL in Tris buffer were distributed in each well, together with 7.5 ?L of the extracts evaluated.
 Quercetin hydrate  and a commercial extract of Rubus idaeus L. were used as positive controls; DMSO alone constitutes the negative one (ODcontrol).
 The plate was filmed and incubated at RT for 20 min. A first OD reading was performed at 410 nm.
 Then, 100 ?L of a solution of N-succinyl-Ala-Ala-Ala-p-nitroanilide 2.06 mM in Tris buffer were distributed in each well. After 40 min incubation, OD reading was performed at 410 nm to assess the percentage of inhibition.
Hyaluronidases are a family of enzymes that degrade hyaluronic acid, a high-molecular-weight glycosaminoglycan of the extracellular matrix.
 Presenting a unique capacity to bind and retain water molecules, this macromolecule is widely distributed in the body and notably at the periphery of collagen and elastin fibers: it therefore plays a major role in skin aging. 
The assays were performed as follows: 150 ?L of a solution of hyaluronidase prepared at a concentration of 13.3 U/mL in hyaluronidase buffer (pH 7) were distributed in each well, together with 7.5 ?L of the extracts evaluated.
 Tannic acid  were used as positive controls; DMSO alone constitutes the negative one (ODcontrol).
 The plate was filmed and incubated at 37 °C for 20 min. A first OD reading was performed at 405 nm. 
Then, 100 ?L of a solution of hyaluronic acid prepared at a concentration of 150 ?g/mL in buffer (pH 5.35) were distributed in each well. 
After 30 min incubation at 37 °C, 50 ?L of CTAB prepared at a concentration of 40 mM in a NaOH solution (2%) were added in each well and OD reading was performed at 405 nm to assess the percentage of inhibition (ODsample).
Responsible for the tensile strength of the skin, collagen constitutes therefore one of the structural units of the extracellular matrix.
 Collagenases are enzymes that cleave the collagen molecule within its helical region and that are more generally involved in the degradation of the extracellular matrix components, thus leading to skin wrinkling.
 The assays were performed as follows: 150 ?L of a solution of collagenase prepared at a concentration of 53 U/mL in tricine buffer (pH 7.5) were distributed in each well, together with 7.5 ?L of the extracts evaluated.
 Tannic acid (1.72 ?M in DMSO) and a commercial extract of Glycyrrhiza glabra L. (3.433 mg/mL in DMSO) were used as positive controls; DMSO alone constitutes the negative one (ODcontrol).
 The plate was filmed and incubated at RT for 15 min. A first OD reading was performed at 345 nm. Then, 100 ?L of a solution of FALGPA (2-furanacryloyl-l-leucylglycyl-l-prolyl-l-alanine) prepared at a concentration of 5.15 mM in tricine buffer were distributed in each well. 
After 30 min incubation, final OD reading was performed at 345 nm to assess the percentage of inhibition (ODsample).
The total polyphenolic content was estimated by the Folin–Ciocalteu method in 96-well plates as follows: 75 ?L of ultrapure water were distributed in each well, together with 15 ?L of the extracts evaluated.
 DMSO alone was used as negative control. 
Then, 25 ?L of a solution of Folin–Ciocalteu reagent/ultrapure water were added in each well. 
After 6 min incubation under agitation, 100 ?L of a solution of sodium carbonate (75 g/L) were distributed in each well. 
The plate was then filmed and incubated at RT in the dark for 90 min. An OD reading was performed at 765 nm: the amounts are expressed in milligrams of gallic acid equivalents (GAE) per gram of extract. 
The standard curve was prepared with gallic acid solutions (concentrations range: 200, 100, 50, 25 and 12.5 ?g/mL).
The total flavonoid content was estimated in 96-well plates as follows: 100 ?L of a mixture of ultrapure water/DMSO (1/1) were distributed in each well, together with 15 ?L of the extracts evaluated (final concentration per well: 100 ?g/mL).
 DMSO alone was used as negative control. Then, 10 ?L of a solution of aluminum trichloride (100 g/L) were added in each well, together with 15 ?L of potassium acetate (1 M) and 100 ?L of ultrapure water. 
The plate was then filmed and incubated at RT in the dark for 40 min. An OD reading was performed at 415 nm: the amounts are expressed in milligrams of quercetin equivalents (QE) per gram of extract. 
The standard curve was prepared with quercetin hydrate solutions.
The fraction fingerprints were obtained using an HPLC Acquity system.
 Separations were performed on an Acquity UPLC Kinetex? C18 column at 25 °C with a flow rate of 0.6 mL/min.
 The injection volume was set at 1 ?L. The mobile phase consisted of water (solvent A) and acetonitrile (solvent B) both acidified with 0.05% formic acid (all of chromatography grade), and was used in multistep gradient mode.
 The gradient was operated as follows: 0–1 min, 5% B; 1–9 min, 5–40% B; 9–15 min, 40–100% B, 15–17 min, 100% B; final isocratic step for 2 min at 5% B. The sample manager was thermostated at 15 °C.
 ESI (electrospray ionization) conditions operated in positive mode were set as follows: source temperature 150 °C, desolvation temperature 500 °C; capillary voltage 3 KV and cone voltage 10 V.
 Nitrogen was used as cone (10 L/hr) and desolvation gas (1000 L/hr).
SPE cartridges  were fitted into stopcocks and connected to a vacuum manifold. 
The sorbent was conditioned with 10 mL of methanol (MeOH), and equilibrated with 10 mL water.
 With the stopcocks opened and the vacuum turned on, the SPE cartridge is then loaded with either 100 mg of Oak2_M or with 10 mL of Oak3D/H2O (1/3 v/v). 
The vacuum pressure was set at 40 kPa. 
After sample addition, the column was washed first with 10 mL H2O, then with 10 mL H2O/MeOH (10/1 v/v) and finally with 10 mL MeOH/dichloromethane (1/1 v/v). 
Sample was eluted twice with 5 mL MeOH (this stepwise elution was preferred to a single-10 mL elution as it improves the final SPE yield).
Color was evaluated using a spectrophotometer Color i? 5 (X-Rite, Grand Rapids, MI, USA) previously calibrated with a white reference. 
An aliquot of each ingredient discolored or not was placed in glass tubes. 
The results were expressed according to the three-dimensional color space CIE 1976 L* a* b*, defined by the International Commission on Illumination.
 The three coordinates denote respectively the lightness of the color (L*), its red-versus-green attribute (a*) and its yellow-versus-blue attribute (b*), and ΔE*ab represents the color difference between two samples (ΔE*ab will have no unit).
A ΔE*ab between 1.00 to 2.50 represents the points at which an average individual starts to visually notice a color difference; if the ΔE*ab is less than 1.00, the color difference is barely perceivable by an average human observer.
As already stated, a series of Mediterranean plants were initially selected over more than 500 for the present study, based on their accessibility and their originality regarding the anti-aging activity. 
From this survey, it appears that crude extract of Q. pubescens leaves displays the best unprecedented anti-aging activities. 
Added to this, the easiness of the raw material supply in the region, and the attractive marketing potential of the resulting cosmetic active induced its selection for further investigations.
First, the extraction of leaves of Q. pubescens was performed with H2O/EtOH 1/1 to cover the larger polarity range possible, hence to recover a maximum of metabolites. Leaves of Q. pubescens collected in two locations were extracted in the same conditions and the effect of the origin of the raw material on the chemical composition of the resulting extract was investigated. 
The various origin of plant material induced slightly different extraction yields; however, no major difference was evidenced in the phytochemical profiles of oak extracts obtained from leaves collected in different locations (data not shown). 
For convenience, the Q. pubescens extract obtained using H2O/EtOH 1/1 will further be referred to as Oak1 in the present article.
The HPLC fingerprinting of this extract revealed the presence of a large group of polyphenols eluting between 14 and 56 min.
The bioactivities of Oak1 were assessed using in vitro bioassays, and were compared to the bioactivities of commercial cosmetic ingredients used for the respective activities tested (positive control) and to the bioactivities of a commercial oak ingredient. 
To characterize the active compounds responsible for the bioactivities evidenced, Oak1 extract was then fractionated over silica gel. The fractionation of 3.5 g of Oak1 led to the recovery of five distinct fractions: F1, F2, F3, F4 and F5. 
The resulting fractions Oak1_F2 to Oak1_F5 were further evaluated for their bioactivities; no further investigation was undertaken for Oak1_F1 as even if this fraction would be interesting in terms of bioactivity, it would not be commercially viable to develop any resulting cosmetic ingredient due to it poor extraction yield.
The crude extract Oak1, as well as fractions Oak1_F4 and Oak1_F5, all presenting a strong anti-oxidant potency, appear to be quite rich in polyphenolic compounds; such correlation between chemical composition and antioxidant activity was already reported in the literature.
 HPLC-ESI-MS analysis of fraction Oak1_F4 reveals that it is mainly constituted of catechin, a flavanol already known to act as a powerful antioxidant.
Positive relationships were also observed between anti-hyaluronidase activity and phenolic content in the cases of fractions Oak1_F4 and Oak1_F5, as well as between anti-elastase activity and flavonoid content in the cases of fraction Oak1_F3 and to a lesser extent, of fraction Oak1_F4, as previously stated in the literature.
From the previous results, it appeared that the molecules responsible for the bioactivities tested are concentrated in the most polar fractions resulting from Oak1 fractionation scheme 1, i.e., the fractions obtained with diethyl ether, MeOH and MeOH/H2O 1/1. 
To gain information about these metabolites, the Oak1 extract concentrated at 50 mg/mL in MeOH was roughly fractionated by semi-preparative HPLC as described in the Materials and Methods section to separate polar (Oak1_PF eluting between 0–7 min; yield: 62%) from less polar compounds. 
Several injections were realized and successive polar/less polar fractions were respectively pulled together to recover enough material to assess their bioactivities the same way as the one of Oak1.
No remarkable bioactivity was observed for Oak1_PF obtained with water added up with 5% of acetonitrile: this fraction is constituted of more polar compounds that the ones extracted in the previous fractions Oak1_F3 to Oak1_F5.
 The less polar compounds extracted in Oak1_LPF appear to be mainly responsible for the activities reported for Oak1: a large amount of polyphenols eluting between 10 and 50 min were notably identified based on their UV spectra and by comparison with standards available at the laboratory.
 In fact, Oak1_LPF present similar anti-inflammatory and anti-hyaluronidase activities, and appear to be a slightly less potent anti-oxidant, compared to Oak1.
 Some interesting anti-elastase activity was reported for Oak1_LPF, revealing a potential antagonistic effect between both fractions, the polar one impeding the activity of the less polar one against this enzyme.
From the two fractionation strategies adopted, it appears that the compounds responsible for the bioactivities of Oak1 are of intermediate polarity. 
The subsequent process adopted to further develop oak-based cosmetic ingredients will be adapted to preferentially extract those compounds and hence potentialize their bioactivities.
Once the active fraction identified, the corresponding natural cosmetic ingredient can be developed. 
The addition of an appropriate cosmetic support, either liquid or solid, can be necessary to facilitate the incorporation of natural actives into a cosmetic formulation.
As already stated in Section 3.1, the compounds responsible for the bioactivities of Oak1 are of intermediate polarity, so H2O/EtOH 1/1 is not the most convenient solvent system for the further development of an oak-based cosmetic ingredient.
 Added to this observation, one can argue that the elimination of water through concentration by vacuum evaporation is highly energy-consuming, and such a solvent system is hence not the most appropriate one for the ingredients’ industrial production. 
To objectivate the active metabolites’ content of the future ingredient and to facilitate the industrial scale-up of its fabrication process, H2O/EtOH 1/1 was replaced by pure EtOH: for convenience, the Q. pubescens extract obtained by 2 h-maceration of Q. pubescens leaves in ethanol will further be referred to as Oak2 in the present article (extraction yield range: 3–5%). 
The bioactivities of Oak2 were assessed using in vitro bioassays. As presented in Figure 9, apart from the promising antioxidant and anti-hyaluronidase activities already evidenced in the H2O/EtOH 1/1 extract Oak1, Oak2 also displays some anti-inflammatory activity and especially some very interesting anti-elastase activity.
Figure 9. Bioactivities of Oak2, the Q. pubescens extract obtained using pure ethanol, compared to the bioactivities of the discolored extract Oak2D, of the discolored extract deposited on maltodextrin Oak2DM and of commercial cosmetic ingredients used for the respective activities tested (positive controls).
The organic solvents used to extract active molecules from a plant also extract the molecules responsible for the plant’s color, which are generally unacceptable in skin care products  and need therefore to be submitted to further processing, including notably a discoloration procedure. 
Discoloration can be performed by adsorption of the undesirable molecule on activated carbon: the powdered activated carbon can easily be added to the liquid extract, and then removed by settling and filtration.
 Several discoloration conditions were tested using varying discoloration durations and various extract/activated carbon ratios.
 The best results were obtained when Oak2’s discoloration was performed with 1% (w/w) of activated carbon for 1 h.
 The resulting appropriately discolored extract Oak2D was recovered after elimination of the activated carbon (recover yield range: 55–60%) and its bioactivities were assessed using in vitro bioassays. 
Maltodextrin, a solid agent used in cosmetics to bind other compounds and stabilize formulas, was then added to the extract Oak2D (maltodextrin/crude extract 2/1 w/w). 
The mixture is then vacuum-concentrated to dryness, and the resulting powder (Oak2DM) is homogenized using pestle and mortar. The bioactivities of Oak2DM, as well as of maltodextrin alone (no activity reported; data not shown), were assessed using in vitro bioassays as already enunciated (at the same concentration as the extracts and fractions).
The solid ingredient Oak2DM developed here appears to be an efficient active to be incorporated in cosmetic anti-age formula. However, some optimization could still be done in the development of this solid oak ingredient.
Some further discoloration trials should be undertaken to reach the same discoloration level or even a better one, without such a mass loss. 
One can also imagine that adjustments in the ratio of maltodextrin added to the discolored extract may potentially lead to less anti-elastase bioactivity’s loss.
Liquid ingredients are preferred to formulate some cosmetics. Propylene glycol is one of the most widely used cosmetic supports: it serves as a humectant, a viscosity decreasing agent and as a solvent, so it is employed in many personal care formulations including facial cleansers, moisturizers, etc. Owing to its polarity, it was tested to directly extract the active metabolites of Q. pubescens leaves: leaves macerate in propylene glycol (dried plant/propylene glycol 1/10 w/w) for 4 h at room temperature. For convenience, the subsequent Q. pubescens extract will further be referred to as Oak3 in the present article.
From these tests, it appeared that the most suitable discoloration parameters consist in the addition of 1% (w/w) of activated carbon for 1 h: the discolored extract further referred to as Oak3D, was recovered after elimination of the activated carbon. From the color measurements presented in Table 2, it appears that the ΔE*ab is less than 1.00, indicating a color difference barely perceivable by an average human observer. Thus, one can conclude that additional discoloration attempts must be undertaken to obtain an appropriately discolored liquid extract.
The bioactivities of Oak3 and Oak3D, as well as the ones of propylene glycol alone (no activity reported; data not shown) were assessed using in vitro bioassays (Figure 10): no interesting bioactivities were evidenced.
Another attempt was then performed using a greater maceration time: oak leaves macerate in propylene glycol (dried plant/propylene glycol 1/10 w/w) for 7 h 30 at room temperature.
The subsequent Q. pubescens extract, referred to as Oak4 displays some promising anti-hyaluronidase, anti-inflammatory and anti-oxidant activities
From these results, it appears quite clearly that maceration time highly influences the bioactivities of the subsequent extract.
Nevertheless, some further discoloration trials should be undertaken to reach appropriate discoloration, while preserving the extremely interesting anti-aging activity of Oak4.
Finally, greener glycols are also currently tested to develop an even more natural cosmetic ingredient.
Accelerated stability testing that was carried out were performed in glass vials at 42 °C to ensure that the ingredients developed meet the intended quality standards as well as functionality and aesthetics when stored under specific conditions.
As no regulation exists regarding how to perform this kind of tests, the specific testing conditions are defined by the manufacturer.
Typically, decisions are made whether the product is stable or not after eight weeks of testing, and a consensus exists that states that if a product is stable after eight weeks at 45 °C, it corresponds to stability after a one-year storage at room temperature.
In the present case, periodic monitoring of those samples is currently undertaken: visual/olfactory evaluation of critical aesthetic properties such as color, fragrance, texture is performed, and the chemical compositions of both ingredients are scrutinized weekly. 
The evolution of the molecular composition of these finished ingredients, and particularly of their phenolic contents, is followed by HPLC in the same experimental conditions
The tests are not over, but so far, i.e., one month after the beginning of the stability test, no modification of the composition of the ingredient was noticed, but further investigations should confirm these observations.
Furthermore, it would be necessary to push these stability tests forwards once the definite formulation has been determined: additional tests should be performed in an aging chamber where the effect of temperature/lighting variations mimicking the ones a finished product is submitted to, from formulation to consumer’s use, could be monitored.
In this article, the R&D process adopted to develop a new objectivated cosmetic ingredient, from the plant sourcing to the actual ingredient formulation is presented in detail through the example of the development of promising natural anti-age ingredients based on Q. pubescens leaves extract.
Application of high throughput screening technologies to natural product samples accelerates considerably the discovery, development and use of natural cosmetic ingredients, but such a screening is still a long-term undertaking 
It was recently suggested that only five in every 100 genetic resources identified as being potentially of interest will ever end up in cosmetic and personal care formulas
In fact, once the ingredient developed, it must pass all the efficacy, quality, shelf life and safety/tolerability (cytotoxicity, skin and ocular irritability) tests right throughout the development chain prior to be launched on the market. 
Only after this array of controls has been undertaken will a formulator consider using this ingredient in an actual finished-product formulation.
Some researchers actually integrate the toxicology assessment directly into the cosmetic ingredient R&D process to avoid an unpleasant discovery at the end of the process, which could lead to the restriction or even the abandonment of the ingredient’s use due to toxicity concerns
The vigilance about worldwide regulation compliance is guaranteed by the U.S. Food and Drug Administration (FDA). At the European level, the Scientific Committee on Consumer Safety (SCCS, replacing the former SCCNFP) establishes and regularly revises guidance notes that contain relevant information on the different aspects of testing and safety evaluation of cosmetic substances
These notes must be adapted at each individual case, depending, for instance, on the nature of the ingredients entering the formulation, on the finished product’s formulation itself, and the frequency and route of consumers’ use of the product.
Hence, such a translation of laboratory research into commercial successes often takes time (up to several years) and manufacturers must back the right horse about market trends many years in advance.
H.P. is grateful to the CIFRE - Conventions Industrielles de Formation par la REcherche - convention (ANRT JYTA) for her Ph.D. financing. 
The objective of this study was to evaluate the potential use of some vegetal raw materials in personal-care products. Four ethanolic extracts (grape pomace, Pinus pinaster wood chips, Acacia dealbata flowers, and Lentinus edodes) were prepared and total phenolics, monomeric sugars, and antioxidant capacity were determined on alcoholic extracts.
 Six of the most important groups of cosmetics products (hand cream, body oil, shampoo, clay mask, body exfoliating cream, and skin cleanser) were formulated. 
Participants evaluated some sensory attributes and overall acceptance by a 10-point scale; the results showed differences among age-intervals, but not between males and females.
The results confirmed that all extracts presented characteristics appropriate for their use in cosmetic formulations and their good acceptability by consumers into all cosmetic products.
Texture/appearance, spreadability, and skin feeling are important attributes among consumer expectations, but odor and color were the primary drivers and helped differentiate the natural extracts added into all personal-care products.
Consumers are increasingly demanding natural ingredients and additives in cosmetic products, as well as the replacement of synthetic compounds with possible negative effects on health and the environment
Antioxidants are preservatives with the function of preventing lipid oxidation of the product. They can act following different mechanisms, i.e., reducing agents, oxygen scavengers, synergistic agents, and chelating agents. More recently, antioxidant-based products have been proposed to protect the skin
Among natural compounds with antioxidant properties, phenolics are the most studied.
Natural phenolics—including benzoic acids, cinnamic acids, and flavonoids—are widely distributed in renewable and abundant sources, such as agricultural, food, and forest products and by-products. 
The utilization of these alternative low cost sources is desirable for the integral valorization of vegetal raw materials and could benefit the economy of the process and the cost of the products.
The potential of selected natural extracts obtained from underutilized and residual vegetal biomass processed with food-grade green solvents as additives in cosmetic products was previously reported. 
The extracts were safe for topical use and enhanced the oxidative stability of model oil-in-water emulsions
Phenolic compounds present a wide variety of activities of interest in cosmetics, such as antioxidant, antimicrobial, anti-inflammatory, or anti-aging.
Formulations enriched in phenolic antioxidants are increasingly used in anti-aging cosmetics as a defense strategy against reactive oxygen species (ROS) 
 In addition, natural phenolic compounds can permeate through the skin barrier, in particular the stratum corneum
Cosmetic products need to be effective and stable, but also the acceptance by the consumer needs to be confirmed.
 Equally important are the favorable benefits on skin health and the desirable sensory attributes, because the incorporation of natural extracts could confer undesirable characteristics and strong colors or aromas, that would limit the acceptance of the product.
Sensory analysis can discriminate the characteristics influencing consumer acceptance and to indicate how they are perceived and, consequently, guide success in the development of new cosmetic products.
 According to Elezovi? et al., the characteristics influencing consumer acceptance are based, first, on its packaging, and then on its smell, appearance, and texture (touch and feel).
Therefore, after the development of a formulation, researchers and cosmetic companies should carry out a sensory evaluation with trained or consumer panels.
Sensory analysis represents a valuable tool, but it is financially expensive and time-consuming.
For this reason, some papers have recently appeared studying the application of instrumental analysis, mainly through rheological measurements, to detect changes of entry ingredients
Cosmetic properties, such as the optimal mechanical properties (firmness), adequate rheological behavior, and appropriate adhesion, could be measured by instrumental analysis.
Other attributes—including, appearance, odor, residual greasiness after application, or the sensation produced by the cosmetic application—play an important role in the acceptability of cosmetic products by consumers.
They are subjective and, consequently sensory evaluation methods should be applied. 
The objective of this work was to formulate six cosmetic products with ethanolic extracts from four vegetal raw materials which provide different types of aromatic families: flower, fruity, wood, and mushroom/earthy.
The reducing power and radical scavenging capacity of the extracts were characterized and the sensory evaluation of the final personal-care products was assessed.
Grape pomace was provided by Destiler?a Galicia. Pine (Pinus pinaster) wood chips, kindly provided by FINSA Orember (Ourense, Spain), were air dried and milled under 1 mm.
Acacia dealbata flowers were collected in forest areas in the surrounding of Ourense (Spain) in Winter 2014 and freshly processed.
Shiitake (Lentinus edodes) was purchased in local markets and was freeze dried and ground before processing.
Pressed distilled grape pomace was extracted with water at a liquid to solid ratio 15 w/w, at 50 °C in an orbital shaker at 175 rpm overnight.
The solid and liquid phases were separated by filtration and the liquid phase was contacted with non-ionic polymeric resins
Before use, resins were rinsed with deionized water at a liquid-to-solid ratio of 5 (w/w). 
Desorption was carried out with 96% ethanol at a solvent to resin ratio 3 (mL/g) in an orbital shaker at 175 rpm and 50 °C. 
The resin was regenerated in 1 M NaOH overnight and further washed with deionized water 
Ground Pinus pinaster wood samples, Acacia dealbata flowers, and ground freeze-dried Lentinus edodes samples were contacted with 96% ethanol in sealed Erlenmeyer flasks at 50 °C in an orbital shaker at 175 rpm overnight.
Six cosmetic model products were formulated with conventional ingredients and with the extracts from the selected sources.
The cosmetics prepared were: hand cream (HC), body oil (BO), shampoo (S), clay mask (CM), body exfoliating (BE), and a skin cleanser (SC). 
The ethanolic extracts—grape pomace extract (GPE), pine wood extract (PWE), acacia flowers extract (AFE), and shiitake extract (SE)—were added to cosmetics dissolved in a minimum amount of ethanol.
These extracts have both the function of antioxidants and additives (colorants and perfumes). Control samples without extracts were also prepared.
Hand cream (HC) contained: paraffinun liquidum (30 g), lanolin (30 g), Kathon CG (0.2 g), and extract (five drops).
Paraffin was slowly melted in a water bath (50 °C) and stirred to obtain an homogeneous mixture, which was neutralized with triethanolamine (if required). The extracts were added to the cold mixture.
The oils were mixed with gentle stirring in a water bath at 40 °C, and once cooled, the extract was added.
Shampoo (S) was prepared with the following ingredients: sodium laureth sulfate (45 wt %), diethanolamine (3 wt %), Kathon CG (0.02 wt %), citric acid (0.01 wt %), extract (five drops) and distilled water. Approximately half of the water volume was mixed with the detergent and the other half was used to dissolve diethanolamine, citric acid and Kathon.
Both solutions were mixed with intense stirring before adding the extract.
Clay mask (CM) was formulated with the following components: sodium laureth sulfate (0.1 g), kaolin (35 g), bentonite (5 g), cetyl alcohol (2 g), glycerin (10 g), Kathon CG (0.2 g), extract (five drops), and distilled water.
Water was incorporated to bentonite and was allowed to stand 24 h until gelification. Cetyl alcohol was melted in a water bath.
The detergent, glycerin, and the antimicrobial agent were added to the bentonite mixture, which was then heated at 40 °C. Kaolin was also added at this temperature, stirring to avoid lumps. The extract was added to the cooled mixture.
Body exfoliating salt scrub (BE) was composed of: sodium chloride (150 g), almond oil and extract (five drops). 
The oil was used in an amount needed to moist the salt, then the extract was added and the mixture was stirred until homogenization.
Skin cleanser (SC) was prepared with: cetyl alcohol (10.5 mL), liquid paraffin (30 mL), distilled water (258 mL), triethanolamine (1.5 mL), Kathon CG (0.6 mL), and extract (five drops). Cetyl alcohol was melted in a water bath at 70 °C and mixed with paraffin under mild stirring. 
Triethanolamine, the antimicrobial agent, and distilled water were mixed with continuous stirring at the previously indicated temperature. The aqueous phase was dropped on the oily phase until it coole and then the extract was added.
The extracts were characterized for phenolic and sugar content and for antioxidant activity. 
The personal care products were characterized for sensorial properties.
Total phenolic content was colorimetrically determined using the Folin–Ciocalteu reagent (Sigma-Aldrich, St. Louis, MO, USA) and expressed as gallic acid (Sigma-Aldrich, St. Louis, MO, USA) equivalents.
All analyses were performed at least in triplicate and are reported on a dry matter basis. Ash content was gravimetrically determined.
The sensory panel consisted of 26 female and 29 male assessors (18–45 years old) recruited from a pool of students and staff of IES Lauro Olmo (O Barco de Valdeorras, Ourense, Spain), without previous experience in sensory analysis.
The six cosmetic samples (about 10 mL) were served in transparent glass containers encoded with three-digit random numbers. Mineral water and paper towels were provided for skin rinsing between samples.
Panelists were asked to fill out a questionnaire evaluating the intensity of the sensory properties by using a 0 to 10 scale (where 0 represents ‘none’ and 10 ‘extremely strong’) in two sessions along one month.
The list contained 15 descriptors or attributes typically used to characterize the skincare products: six appearance attributes (gloss, color, odor intensity, odor preference, firmness/consistency, creaminess/texture/appearance) and eight skin parameters (spreadability, penetration, softness, skin odor intensity, skin odor preference, skin odor persistence, skin gloss, and skin feel).
Finally, participants were asked to rate their global appreciation of the product on a 10-point scale to report which extract they preferred in each formulation. 
Assessors valuated the appearance attributes during the first session; the skin parameters and the comparison of the six personal-care products to the global score were recorded in the second session.
Intensity values from sensorial data were analyzed by a two-factor (extract, cosmetic) analysis of variance (ANOVA) test using Excel software. 
A Fisher LSD post hoc test (p < 0.05) was used to test the significance of the relative mean differences among the samples. 
Differences among extracts and sample formulations were obtained from preference and descriptive data evaluated by means of principal component analysis (PCA) using the program Statistica 8.0 (Statsoft Inc., 2004, Tulsa, OK, USA).
The phenolic content in the extracts was higher for the grape pomace and acacia flower (18 wt %), and very low for the mushroom, which contained sugars and polyols (threalose, mannitol, and arabitol).
The increased phenolic content of the extracts led to increased ABTS radical scavenging capacity and reducing capacity, except for the grape pomace extract. 
The most active radical scavengers were the acacia flower extract (AFE), followed by the grape pomace extract (GPE) and the pine wood extract (PWE), with 50–70% of the activity of Trolox. The highest reducing power was also found for AFE.
Many natural products, botanicals, or waste materials—derived from agricultural products, foods and beverages—can be used in cosmetics products
Sensory test was carried out to evaluate the possibility of using natural extracts as ingredients of some cosmetic preparations and their acceptability by consumers. 
Independently of the antioxidant activity, the ethanolic extracts were added to provide their odoriferous characteristics to the different cosmetic formulations and to evaluate their acceptance by the consumers.
Likewise, the color differed with raw material too and the volunteers scored also this difference.
Personal-care products from acacia flowers extract (AFE) always showed an intense yellow color
Sensory analysis was performed to determine the preference for the natural extracts, because the composition of the individual formulations was the same, except in this ingredient.
A control sample which did not contain any extract from the studied vegetal raw materials was used for reference.
The most preferred and valued attributes in all cosmetics were spreadability, softness, consistence/texture, and skin feel, but the ANOVA results showed that these attributes in each cosmetic product were comparable and the use of the different extracts caused only a significant effect (p < 0.05) on two parameters: color and odor.
Participants from the two genres accomplished the sensory analysis (26 women and 29 men), and, as can be seen in Figure 2, no great differences between them were found.
Only four samples demonstrated significant differences: women evaluated better than men the acacia flower extract when it was included in the hand cream and exfoliating preparations, and the control-exfoliating and the shampoo with grape pomace extract obtained better scores with men than with women.
Female participants valued body oil and clay masks better than males, and, on the contrary, men valued the shampoo more.
Hand cream elaborated with acacia flowers or shiitake attained the best scores, with 7.20 and 7.04 points, respectively.
From the four assayed raw materials, the least preferred extracts in all cosmetics were red grape pomace and pinus wood ethanolic extracts.
The average overall preference showed that these extracts were best valued as aromatic additives in the shampoo, and the worst score was attained by the exfoliating body. 
The cosmetic most valued with the acacia or shiitake extracts were the hand creams, and the worst was the body exfoliating cream. 
 Control samples (without any added extracts) achieved similar scores than when GPE and PWE were added into all personal-care products, except in shampoo, where it was obtained the best punctuation along with the shiitake extract.
The participants were also divided into three age-segments: <20, 20–30, and 30–45 years, with 20, 19, and 16 persons, respectively.
This last group perceived acacia and shiitake extracts with the significant highest values for all formulations, revealing the influence of color and odor of these natural extracts 
In opposition, the participants under 20 years of age preferred the extracts obtained from pinus wood and grape pomace or the control sample (without any extract), except in hand cream.
These two extracts received lower score in the group of older participants.
Consumers in the 20–30 years old segment evaluated samples with the highest overall preference values in all personal-care products, and the preferred extracts were acacia flowers and shiitake extracts.
The sensory characterization confirms which properties mostly influence consumer acceptance. 
All volunteers considered that the different tested personal-care products have a good spreadability, softness, and good skin penetration ability and posterior skin feeling; but also a pleasant color and fragrance.
These results have shown that a variety of plant materials can be used as additives in cosmetic products to supply color and aroma
Principal component analysis was performed to know how consumer acceptance is based on sensory attributes.
The interrelationships among the extracts from natural raw materials used in personal care-products and sensory descriptors showed that the first two factors explained 88.3% of the total variance among the extracts. 
The first component accounted for 70.5% of the data variability and the second for 17.8%.
In the PCA the extract samples are clearly grouped into two clusters. Cluster 1, located in the upper half, was associated with the cosmetics elaborated from acacia flowers and shiitake extracts, which had the greatest acceptance.
Cluster 2, in the positive part of Factor 1 and in the negative part of Factor 2, was characterized by the other two extracts (grape pomace and pine wood) and the control (without added extract). No differences between different cosmetic formulations were found.
All products were well-tolerated because any visible skin irritation or erythema was observed. 
Besides expected appearance, spreadability, softness, and skin feeling, the color and odor also play an important role on overall preference and, consequently, on purchase intent.
According to the obtained results, fragrance and color were two important attributes for consumer preference and they are essential additives to make personal-care products, even, cosmetic companies use colors in packaging design to communicate the properties of their fragrances
Between the four assayed vegetal extracts, the floral aroma and yellow color provided by the acacia flower extract were evaluated higher by all consumers, independently of genre or age; likewise, this ethanolic extract also presented the highest in vitro antioxidant activity.
Consumers are increasingly rejecting synthetic chemicals in beauty and cosmetic products and demand natural products.
In this study, ethanolic extracts from different raw materials were added to some personal-care products and sensory analysis was carried out to evaluate some attributes such as color, aroma, and texture, and the overall acceptability by consumers.
Results have shown that the ethanolic extracts obtained from a flower, a mushroom, a tree, or agricultural waste (grape pomace) can be valorized and they have a potential application as an ingredient for cosmetic formulations.
Pollution from air and sunlight has adverse effects on human health, particularly skin health. It creates oxidative stress, which results in skin diseases, including skin cancer and aging.
Different types of antioxidants are used as preventative actives in skin-care products.
However, they have some limitations as they also scavenge oxygen. 
Recently, spin traps are being explored to trap free radicals before these radicals generating more free radicals (cascading effect) and not the oxygen molecules.
However, not all spin traps can be used in the topical cosmetic skin-care products due to their toxicity and regulatory issues.
The present review focuses on the different pathways of reactive oxygen species (ROS) generation due to pollution and the potential use of spin traps in anti-pollution cosmetics to control ROS.
The World Health Organization (WHO) has recognized the urban pollution as one of the most important environmental issues in the world. 
Over 99% of the urban population in Asia is regularly exposed to concentrations of air pollutants that are above the WHO recommendation level. 
According to the latest urban air quality database, more than 100,000 inhabitants in 98% of cities in low- and middle-income countries do not live in areas with good or healthy quality air (as per WHO air quality guidelines).
On the contrary, high-income countries are improving their air quality.
Air pollution is comprised of various particulate matters (PMs) that can cause skin diseases, cancer, pulmonary, and cardiovascular diseases
The increased ambient PM from industrialization and urbanization is highly associated with morbidity and mortality worldwide
Free radicals or reactive chemical species exhibit a single unpaired electron in an outer orbit to form the unstable configuration creating energy and releasing it through reactions with adjacent molecules, such as proteins, lipids, carbohydrates, and nucleic acids
Nanosized particles from traffic sources are the most harmful components of ambient PM because of oxidative stress due to their small size and large surface per unit mass, and are highly reactive towards biological surfaces and structures 
Additionally, nanoparticles can carry organic chemicals and metals to mitochondria and generate ROS [10].
Additionally, Polycyclic Aromatic Hydrocarbons (PAHs) adsorbed on the surface of airborne PM can activate xenobiotic metabolism to convert PAHs into quinones and producing ROS.
Two types of antioxidants that can help scavenge ROS are (i) enzymatic antioxidants such as superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), guaiacol peroxidase (GPX), glutathione reductase (GR), monodehydroascorbate reductase (MDHAR), and dehydroascorbate reductase (DHAR); and (ii) non-enzymatic antioxidants such as ascorbic acid (AA), reduced glutathione (GSH), α-tocopherol, carotenoids, flavonoids, and the osmolyte proline. 
 A co-factor is an ion or a molecule that binds to the catalytic site of an apoenzyme rendering it active.
In addition to antioxidants, co-factors such as zinc also play an important role in the free radical induced oxidative damage.
It is five to six times more concentrated in the epidermis than the dermis.
Zinc is an essential element of more than 200 metalloenzymes including the antioxidant enzyme and CuZnSOD
Topical divalent zinc provides antioxidant photoprotection for skin either by replacing redox active molecules such as iron and copper at critical sites in cell membranes and proteins or by inducing the synthesis of metallothionein like sulfhydryl-rich proteins that protect against free radicals 
The conventional antioxidants react with free radicals to convert the ROS into water. 
However, antioxidants may also contribute to hypoxia in deep tissue by indiscriminately converting both normal oxygen and ROS molecules to water
On the other hand, spin traps have the ability to scavenge or stabilize free radicals before their deterioration and help reduce their cascade effect on other molecules to generate more free radicals. Spin traps can selectively trap ROS as opposed to antioxidants
The present review discusses ROS and oxidative stress pathways arising due to pollution, the potential use of spin traps against ROS and oxidative stress, and their limitations.
Ambient PM can penetrate the skin either through hair follicles or trans-epidermally, and PM-bound PAHs generate ROS.
The long-term exposure to air pollution can lead to extrinsic skin aging through oxidative stress generated by the particles themselves and/or by associated PAHs.
Moreover, PMs have been found to disrupt stratum corneum integrity by 2-fold and mildly damaging tight junctions. 
Additionally, an increase in soot (per 0.5 × 10?5/m) and particles from traffic (per 475 kg/year/km2) has been associated with 20% more pigment spots on the forehead and cheeks 
M induces oxidative stress through the production of ROS and secretion of pro-inflammatory cytokines such as Tumor necrosis factor (TNF)-α, Interleukin (IL)-1α and IL-8 
 The increased production of ROS such as superoxide and hydroxyl radical by PM exposure increases matrix metalloproteinases (MMPs) such as MMP-1, MMP-2 and MMP-9. MMPs are responsible of the degradation of collagen and lead to the increase in inflammatory skin diseases and skin aging
 In addition, environmental cigarette smoke, which is well known as an oxidizing agent, is responsible for androgenetic alopecia (AGA).
The ultrafine particles including black carbon and PAHs enhance the incidence of skin cancer.
Overall, increased PM levels are responsible for the development of various skin diseases via the regulation of oxidative stress and inflammatory cytokines.
Antioxidant and anti-inflammatory drugs may be useful for treating PM-induced skin diseases.
The onset of systemic lupus erythematosus (SLE), an immune-complex-mediated multi-systemic autoimmune condition, can be flared by various environmental factors such as cigarette smoke, alcohol, occupationally- and non-occupationally- related chemicals, ultraviolet (UV) light, infections, etc.
Sensitive skin is induced by various environmental factors such as UV light, cold, heat and air pollution. 
The activation of cutaneous endothelin receptors and transient receptor potential (TRP) channels represent a mechanism by which external environmental stimuli are transferred to individuals with sensitive skin
Additionally, UV irradiations upregulate proinflammatory lipids including lysophosphatidic acids (LPA) such as LPA 18:1
These upregulated proinflammatory lipids are agonists of TRPV1 (transient receptor potential cation channel subfamily V member 1 or the capsaicin receptor or the vanilloid receptor 1) in the skin
 TRPV1 contributes to thermal hyperalgesia and mechanical allodynia and trigger the sensation of pain
Toll-like receptors (TLRs) are cellular sensors that recognize pathogens and can be expressed on various cell types including keratinocytes, Langerhans cells, mast cells, and fibroblasts in the skin
Upon stimulation with exogenous or endogenous ligands, TLR3 cells are intimately involved in the pathogenesis of infectious or inflammatory skin diseases such as viral infections or allergic and irritant contact dermatitis, and itching sensations in the skin 
Atopic dermatitis (AD) is a chronic skin disorder which is characterized by pruritus and recurrent eczematous lesions that are accompanied by T-helper (Th)2-dominated inflammation. 
AD is characterized by complex interactions between genetic and environmental factors, such as skin barrier dysfunctions, allergy/immunity, and pruritus. 
Filaggrin is one of the key proteins involved in skin barrier function. 
Th2 cells produce interleukin (IL)-31 which can provoke pruritus and other Th2 cytokines can decrease filaggrin expression by keratinocytes.
AD can be treated by newly developed drug, Dupilumab (as a post treatment and not as preventative measure), which can bind to IL-4 receptor α and inhibit downstream signaling induced by IL-4 and IL-13
UV irradiation is one of main environment pollutants that can cause human carcinogens.
 UV-C is absorbed by oxygen and ozone in the Earth’s atmosphere and does not have any significant impact on the skin
However, the longer wavelength, UV-B and UV-A radiations, have significant effects on the biota.
UV irradiations are responsible for melanoma formation [31]. The DNA damaging, carcinogenic, inflammatory, and immunosuppressive properties of UV radiations contribute to initiation, progression, and metastasis of primary melanoma
The changes in ROS signaling pathways have the damaging action of UV-A and UV-B irradiations on the skin
Moreover, the overproduction of ROS may stimulate malignant transformation to melanoma.
UV-A light can deeply penetrate into the skin generating ROS that damages DNA leading to 92% of malignant melanoma. 
 On the contrary, UV-B light, that has a shorter wavelength than UV-A light, causes sunburn, induces DNA damage leading to the apoptosis of keratinocytes
Therefore, UV-B light affects the skin directly compared to UV-A light and is responsible for 8% of total melanoma production
Mechanistically, the UV-B light exposure results in (i) the formation of covalent linkages between pairs of thymine and cytosine bases in DNA, (ii) the formation of pyrimidine (cyclobutane) dimers and (iii) the excitation of DNA of the skin cells.
Additionally, the DNA polymerase incorporates an incorrect base opposite to an abnormal base leading to a DNA mutation during the replication process, which, in turn, can cause skin cancers.
In addition to the DNA mutation, some of the major side products such as 6-4 photoproducts (6-4 PPs) pyrimidine adducts and Dewar valence isomers are also formed by the photoisomerization of 6-4 PPs due to exposure of the skin cells to UV-B light (>290 nm)
Most of these genetic lesions are generally corrected by nucleotide excision repair.
The genetic information may be permanently mutated if nucleotide excision repair dies not occur.
After UV-A irradiation absorption, endogenous photosensitizes such as flavins, NADH/NADPH, urocanic acid, and some sterols present in tissue are converted to their long-lived triplet state, which in turn can transfer energy to oxygen molecules to form an energetically excited and highly reactive singlet oxygen.
Additionally, a novel class of UV-A photo-sensitizers comprised of skin biomolecules based on 3-hydroxypyridine derivatives such as enzymatic collagen cross-links, B6 vitamin, and glycation end products in chronologically aged skin are capable of skin photooxidative damage
UV-A-irradiated cultured human melanocytes can be photosensitized by chromophores such as pheomelanin and/or melanin intermediates
In addition, UV-B natural chromophores may exhibit similar phototoxic properties. UV-B-sensitized tryptophan produces singlet oxygen (1O2) and superoxide radicals (O2?.), and these reactive forms of oxygen may contribute to membrane-, cytoplasm- and DNA-damaging effects
Singlet oxygen, hydroxyl radical and hydrogen peroxide are ROS that can also produce oxidative stress in cells and organisms
Oxidative stress is the imbalance between ROS production and a biological system’s ability to detoxify these reactive intermediates.
The oxidative stress is considered as a critical pathophysiological mechanism in cancererogenesis 
Reactive chemical species can reach DNA by diffusion and the resultant bimolecular reaction will damage the DNA
Singlet oxygen interacts preferentially with guanine to produce 8-oxo-7,8-dihydroguanine after losing two electrons.
 Additional removal of two electrons from 8-oxo-7,8-dihydroguanine can yield highly mutagenic spiroiminodi-hydantoin (Sp) R and S stereoisomers that are capable of causing G→T and G→C conversions, and, in turn, this may initiate cancer 
Typical levels of ozone that are recorded in urban environments are in the range of 0.2 to 1.2 ppm
 This century will see an increase in ozone levels, which will have adverse effects on skin 
Ozone is a potent oxidant that can react with a variety of extracellular and intracellular biomolecules and damage the barrier function of the epidermis
The cytotoxicity of ozone is due to its capability of antioxidant depletion and its interaction with unsaturated lipids to generate damaging free radicals or toxic intermediate products.
 Ozone exposure can influence antioxidant levels and oxidation markers in the outermost stratum corneum layer 
The changes in the oxidant levels and oxidation markers induce cellular stress responses in the deeper skin cells 
The chronic exposure of the skin to environmental stressors can overwhelm the skin’s defensive system comprised of both enzymatic and non-enzymatic low molecular weight antioxidants, and induces persistent damage to cutaneous tissues. 
Therefore, antioxidants can be used as a defensive approach against the pollution induced oxidative stress.
However, the antioxidant protection is limited by the first-pass metabolism and the lack of ability to sustain enough antioxidants in the skin. 
Additionally, the topical application of single antioxidants is not enough to protect the skin in a comprehensive manner; therefore, the synergistic action of diverse types (enzymatic and non-enzymatic) of antioxidants may better protect against oxidative stress. In this regard, the combination of ferulic acid with vitamin oxidants such as vitamin C and vitamin E has been found to provide double protection to the skin from environmentally induced oxidative stress
 These findings may be helpful to researchers to find new ways of preventing or neutralizing the toxic effects of O3 in cutaneous tissue. 
The exposure of normal human epidermal keratinocytes (NHEK) to ozone (0.3 ppm) can result in an increase in protein and messenger RNA (mRNA) expression of the family of cytochrome P450 (CYP) isoforms (CYP1A1, CYP1A2 and CYP1B1). Additionally, NHEK exposure to ozone results in nuclear translocation of the aryl hydrocarbon receptor (AhR) and in phosphorylation of epidermal growth factor receptor (EGFR).
Moreover, the effect of ozone on events downstream of EGFR can result in an increased activation of phosphoinositide 3-kinase and phosphorylation of protein kinase B and mitogen-activated protein kinases [73]
Acute ozone exposure depletes skin vitamins C and E and induces lipid peroxidation in upper epidermal layers
The dramatic increase of basal and squamous cell skin cancer in the past few years has been associated with stratospheric ozone depletion caused by ozone depleting substances (ODS) of anthropogenic origin and resultant higher UV-B radiations
Skin aging leads to a progressive loss of structure and function, which can be influenced by both intrinsic and extrinsic factors.
Oxidative stress induced by ROS plays an important role in the aging process [76]. 
Mitochondria is the major source of cellular oxidative stress and causing cutaneous aging and senescence.
Antioxidants are generally produced to counteract the oxidative stress.
However, due to environmental stress, elevated ROS levels can overwhelm endogenous cellular antioxidant mechanisms
This can lead to an imbalance in tissue oxygen homeostasis, with oxidant effects outweighing antioxidant effects, and, therefore, the cellular environment becomes oxidatively stressed 
Oxidation of lipids by ROS can damage cellular structures and result in premature cell death
In addition, the interaction with nuclear and mitochondrial nucleic acids results in mutations that predispose them to strand breaks 
Extrinsic skin aging is generally influenced by environmental factors and external stressors such as UV radiation, pollution and lifestyle factors that stimulate the ROS production and oxidative stress
The properties of antioxidants such as preventive, radical scavenging, repair and de novo, and the adaptations are described below. 
The first line of defensive antioxidants suppresses the formation of free radicals, but the precise mechanism and site of radical formation in vivo are not well established so far. 
The metal-induced decompositions of hydroperoxides and hydrogen peroxide is assumed to be one of the important sources of free radicals. 
Some antioxidants reduce hydroperoxides and hydrogen peroxide to alcohols and water, respectively, prior to the generation of free radicals. Enzyme antioxidants such as glutathione peroxidase, glutathione-S-transferase, phospholipid hydroperoxide glutathione peroxidase (PHGPX), and peroxidase decompose lipid hydroperoxides to corresponding alcohols.
 PHGPX is a unique enzyme antioxidant as it can reduce hydroperoxides of phospholipids integrated into biomembranes. 
Antioxidants, glutathione peroxidase and catalase reduce hydrogen peroxide to water. The second line of defensive antioxidants scavenge the active radicals to suppress chain initiation and/or break the chain propagation reactions.
 Endogenous radical-scavenging antioxidants can be hydrophilic and lipophilic in nature. Hydrophilic radical-scavenging antioxidants are vitamin C, uric acid, bilirubin, albumin, and thiols, while lipophilic radical-scavenging antioxidants are vitamin E and ubiquinol. 
Vitamin E is widely treated as the most potent radical-scavenging lipophilic antioxidant. 
The third line of defensive antioxidants comprised of the repair and de novo antioxidants such as proteolytic enzymes, proteinases, proteases, and peptidases that are present in the cytosol and in the mitochondria of mammalian cells. 
These antioxidants recognize, degrade and remove oxidatively modified proteins and prevent the accumulation of oxidized proteins. 
Additionally, the DNA repair systems play an important part of the total defense system against oxidative damage. 
Enzymes such as glycosylases and nucleases repair the damaged DNA. Furthermore, there is an important function called adaptation that produces the signal for the production and reactions of free radicals to induce the formation and transport of the appropriate antioxidant to the right site.
 Antioxidants have been used to reduce the effect of oxidative stress and photoaging or repair the damaged skin. However, the efficacy of antioxidants to protect the skin is dependent on potency as well as its stability of antioxidants in the skin or in the formulation.
 Antioxidant mixtures protect against ozone induced damage in human reconstructed skin models.
 Recently, Valacchi et al. have demonstrated that antioxidant mixtures comprised of L-ascorbic acid, alpha-tocopherol, ferulic acid, and phloretin can restrict ROS production induced by ozone exposure in a reconstructed human epidermis (RHE) model in addition to the prevention of ozone-induced oxidative damage in human keratinocytes. 
As discussed in the next section, spin traps do not react with unpaired electrons of oxygen and trap free radicals only. 
Vitamin C, which is known to be antioxidant, can also be an oxidant to form the ascorbate free radical. 
Spin traps do not form free radicals like Vitamin C.
Janzen and Blackburn coined the term “spin trap” for trapping free radical intermediates.
 The fundamental mechanism of “spin trap” action is different from traditional antioxidants such as Vitamin A or C. Spin traps are quick to trap or stabilize free radicals before deterioration of free radicals. 
Furthermore, they can reduce the free radical cascade effect on other molecules to generate more free radicals. Spin traps essentially scavenge the free radicals and selectively trap ROS in comparison to antioxidants. 
As discussed before, the antioxidants chemically react with the free radicals to convert the ROS into water to terminate the chain reaction.
 Antioxidants might be counterproductive as they may contribute to hypoxia (lack of oxygen) in deep tissues by indiscriminately converting both normal oxygen and ROS molecules to water. 
On the other hand, spin traps react only with the ROS in a passive way by intercepting it before any damage is done. 
It can differentiate between good oxygen molecules and ROS (which are harmful).
The spin trapping technique consists of using a nitrone or a nitroso compound to “trap” the initial unstable free radical as a “long-lived” nitroxide that can be observed at room temperature using conventional Electron spin resonance (ESR) spectrometric procedures.
Nitrones, particularly PBN, have been studied for anti-aging properties.
 PBN suppresses the amount of ROS produced in mitochondrial respiration. With their unique actions to control ROS, spin traps also suppress pro-inflammatory conditions and destroy age-inducing free radicals in skin.
 Therefore, they can be utilized in skin anti-aging products, scar-reducing products, and used to treat inflammatory conditions such as rosacea and sunburn.
 Additionally, spin traps can control cellular oxidation states and oxidatively sensitive enzyme systems, and exhibit anti-irritant and anti-microbial properties in topical skin-care formulations.
 Particularly, PBN scavenges the hydroxyl free radicals generated by α-hydroxy acids in the Fenton reaction.
Fuchs et al. have studied the toxicity of different spin traps, and estimated the irritation potency (IP) based on erythematous and odematous lesions; II of spin traps estimated at 100 mM is provided in. 
Based on II, authors have found that the nitroxide precursors and nitrones can be classified clinically non-irritant, 2,2,3,4,5,5-hexamethyl-imidazoline-1-yloxyl (Imidazo), 5,5-dimethyl-1-pyrroline N-oxide (DMPO)) to slightly irritant (3,3,5,5-tetramethylpyrroline-N-oxide (TEMPO), 2,2,5,5-tetramethyl-3-oxazolidinoxyl (DOXO), PBN) as per the Draize protocol. 
PBN, DOXO, and TEMPO are found to be non-irritant at 10 mM; therefore, a low amount of these three spin traps can be used in cosmetic formulation to avoid toxicity. 
Further research may be needed to find maximum safe concentrations of these three spin traps.
Authors have also found a significant increase in the trans-epidermal water loss values by 100 mM of TEMPO, DOXO and PBN and 2,2,6,6-tetramethyl-1-hydroxypiperidine (TOLH), hydroxylamine-TEMPO and its major skin metabolite did not cause skin irritation. 
The nitroxide irritancy potency is found to be TEMPO > DOXO > Imidazo = PROXO. This irritancy potency is further found to be in inverse order (Imidazo = PROXO > DOXO > TEMPO) of nitroxide biostability in murine and human skin.
Additionally, nitroxides and nitrones did not show the sensitizing effect as per the Magnusson and Kligman test. 
Therefore, the nitroxide precursors and nitrones tested have exhibited a low potential of acute skin intolerance. Janzen et al. found that the lethal dose of PBN was found to be approximately 100 mg/100 g bodyweight (0.564 mmol/100 g), suggesting that PBN is non-toxic. 
DMPO was found to be the least toxic (no toxic signs at twice the lethal dose for PBN), whereas 2,6-difluoro-PBN and M4PO (3,3,5,5-tetramethyl-1-pyrroline-N-oxide) were the most toxic as both cause death at 1/8 of the PBN-equivalent lethal dose.
 Non-irritating spin traps have low TEWL (13 g/m2·h–16 g/m2·h), whereas DOXO is a slight irritant with good TEWL (24 ± 5 g/m2·h). 
Theoretically, a combination of spin traps with non-irritation and high TEWL can be used in skin care formulations. 
Moreover, Haselof et al. and Janzen have studied the cytotoxicity (the inhibitory concentration at half maximum, IC 50 mM; 50% cell viability) of spin traps on bovine aortic endothelial cells and found that DMPO is least toxic (138.34 ± 2.22 mM) followed by PBN (9.37 ± 0.26 mM), but TEMPO is found to be highly cytotoxic (0.72 ± 0.05 mM). 
DMPO is least toxic but may not hold trans-epidermal moisturization as it exhibits low TEWL. Comparing all properties, PBN has low toxic and provide good TEWL and can be used alone or with DMPO (least toxic but low TEWL) in cosmetic formulations.
PBN, other nitrone-based and nitroso-based spin traps can ameliorate the cellular dysfunction in tissue partially due to high energy oxygen and hydroxyl free radicals, and enhance recuperation of the tissue. 
Therefore, PBN is used as an anti-alopecia agent to stimulate cosmetic hair growth. 
A study by Barclay et al. revealed that PBN exhibited only retardant (not antioxidant) activity during peroxidation of linoleate (in lipids) initiated by lipid-soluble di-tert-butyl hyponitrite or azobis (2-amidino propane hydrochloride) in sodium dodecyl sulphate micelles.
In the near future, PBN or other suitable spin traps (along with other actives/antioxidants) may also need to be included in cosmetic products to reduce or stop ROS and other free radicals generated by high frequency—high energy (HFHE) visible light (λ = 400–450 nm), near-infrared light (NIR) (λ = 760–3000 nm) and blue light (λ = 450–495 nm). 
This is important because the free radicals generated by the HFHE visible light can potentially affect 40 skin related genes that can attenuate the healing process leading to weak barrier functions, inflammation and un-even pigmentation to the skin.
 Additionally, NIR light has been shown to create free radicals.
 Both HFHE and NIR can produce MMP-1 and MMP-9 leading to aging and degradation of collagen in the skin.
 Moreover, blue-violet light at high doses may also generate free radicals.
 Blue light is used to treat acne, psoriasis and AD through ROS production and its short-term use in clinics is found to be safe.
 PBN like spin traps can help reduce the effect of prolong exposure of blue light induced free radicals on the (healthy, diseased or old) skin and further reduce the aging effect.
 This is particularly applicable for our current (modern) lifestyle due to our extensive exposure to digital appliances such as laptop, smart phone, television, etc. 
Further research is needed to ascertain the effect of prolonged exposure to blue light from optoelectronic appliances on the skin under various conditions (environmental or age-related), in order to develop new spin traps or formulations to enhance the protection of the skin.
Spin traps, lipophilic in nature, can be encapsulated by lipid spherules or vesicles to release into the epidermis and dermis layers.
 The diffusion constant of these encapsulated systems in the stratum corneum is found to be <1 × 10?7 cm2·s?1. The diffusion coefficient can be varied by varying the composition of vesicles.
Different molecular weights of sodium hyaluronate are known to transfer biomacromolecules and other actives transdermally, and can also be used for dermal delivery of other actives including spin traps.
 Hypothetically, low viscous (less than 300 cPs) oil-in-water formulations such as serums containing low viscous sodium hyaluronate, medium viscous hydrogels  and creams with viscosity  can be used to transfer actives including spin traps to different parts of the skin.
 For example, low viscous serum containing low molecular weight (MW) sodium hyaluronate (<50 kDa) may transport actives to cell–cell junctions, hydrogels with medium MW sodium hyaluronate (50–300 kDa) will restrict transfer of actives predominantly to epidermis and supply moisturization, and high viscous cream with high MW sodium hyaluronate (>1 MDa) (containing 30–60% oil phase) can restrict actives to stratum corneum or top skin layers and reduce TEWL due to a high oil phase. 
Additionally, different weights of sodium hyaluronate may provide moisturization to all skin layers from inside out.
 With this three-step process, actives with spin traps can provide thorough protection to all levels of the skin structure from inside out. 
Additionally, chemical enhancersmor polymeric hydroethanolic systems can be used for the controlled dermal delivery of spin traps and actives.
In the current global cosmetic market, the spin traps (particularly PBN) are included along with other antioxidants or cosmeceuticals in a few high-end cosmetic products, mostly for the antiaging purposes.
 The number of antipollution cosmetics has increased by 40% between 2011 and 2013, which represent a market share of 28% in the Asia-Pacific region. 
Anti-pollution cosmetics accounted for 1% of newly launched beauty products worldwide in 2016, except in Europe where the anti-pollution cosmetic trend is stagnating.
 This trend of using spin traps in cosmetics shall increase in the next few years. 
However, the toxicity and regulatory constraints of spin traps need further studies before being included into topical skin-care products to treat skin-indications.
Pollution from air and sunlight has an adverse effect on the human health, particularly the skin health due to the oxidative stress, which can induce skin diseases such as skin cancer and aging. 
Different types of antioxidants have been used as preventative actives in skin-care products to scavenge free radicals. 
However, antioxidants have some limitations, as they can block the normal oxygen in the organs, which is helpful for the skin rejuvenation. 
Recently, spin traps are being explored to trap ROS before free radicals generate more free radicals in the cascading effect, with PBN being one of the spin-traps used in cosmetic products. 
Spin traps can specifically scavenge free radicals before the cascading effect and will not scavenge normal oxygen. However, not all spin traps can be used in the topical cosmetic skin-care products currently due to toxicity and regulatory issues.
Skin moisturizing products generally seek to increase the water content of the stratum corneum, which depends on the barrier properties and the water gradient across the epidermis. 
High water content in the stratum corneum and low transepidermal water loss (TEWL) are among the main features of healthy skin.
The electrical capacitance method has been the most used among the several methods proposed for the determination of the water content of the epidermis (WCE), because it uses low frequency current and is little affected by temperature and relative humidity.
The evaluation of TEWL is a well-established method in dermatology to assess the integrity of the skin barrier. When skin is damaged, its barrier function is impaired resulting in increased water loss.
TEWL measurements allow observation of disturbances in the protective function of the skin at an early stage even before they are visible. Normal skin allows loss of water only in small amounts. 
In the case of many topical diseases or dry skin, the loss of water is much greater. 
The determination of TEWL is also an important support for investigating skin irritation that occurs due to various physical and chemical influences.
Licuri (Syagrus coronata) and catol? (Syagrus cearensis) are Brazilian palm trees from which oils containing a high content of saturated and unsaturated fatty acids (including oleic, linoleic, lauric and palmitic acid) are extracted. 
These fatty acids give emollient properties when incorporated into topical formulations.
From spent coffee grounds—a residue of coffee from homes and industries—it is possible to extract an oil with a high content of unsaturated fatty acids, predominantly linoleic acid, which makes it an alternative for cosmetic application.
Currently, polyunsaturated fatty acids have been used in the production of cosmetics to improve the appearance and health of the skin. 
Creams enriched with linoleic acid are especially related to reduction of dryness and problems of desquamation, thus providing brightness and softness to the skin.
Saturated and unsaturated fatty acids are in the natural composition of said oils giving them emollient properties when incorporated into dermocosmetic formulations. 
Consequently, it is of great importance to investigate the characteristics of these oils, seeking to demonstrate their moisturizing properties and to use these oils as new ingredients with proven efficacy and safety.
Nonionic o/w creams containing 10% weight/weight (w/w) of oils from licuri (LIC Oil Cream), catol? (CAT Oil Cream), spent coffee grounds (SCOF Oil Cream), sweet almonds (SwA Oil Cream), and one formulation without any oil (No Oil cream) were prepared.
 Sweet almond oil was used as a positive control. To prepare the creams, the oily and aqueous phases were heated separately to 70 ± 5 °C, maintaining stirring at 1000 rpm for 30 min, then the oily phase was added to the aqueous phase and the system was mixed with constant agitation until the temperature reached 25 °C. The carbomer was neutralized using a sodium hydroxide 20% (w/v) solution.
 Catol? and licuri oil were extracted from nuts using a hydraulic press. The spent coffee grounds oil was extracted through a Soxhlet extractor.
The pH of the formulations was determined by the pH 21 pH meter (Hanna, Woonsocket, RI, USA). 
The viscosity and rheological properties of the creams were determined at ambient temperature using the Digital Viscometer (Rheology (International) Shannon, County Clare, Ireland). 
The size distribution was measured by light scattering using the Zetasizer? Nano-ZS90 (Malvern Instruments, Malvern, UK). All samples were analyzed by dilution 1:100 with water.
A total of 30 healthy female subjects, 18–40 years old and having Fitzpatrick skin types II, III, and IV, participated in this study after having given their written informed consent. 
The exclusion criteria were the presence of any dermatitis or other skin or allergic diseases and a smoking habit. Volunteers were instructed not to apply any topical formulations on the test sites for two days before and during the study.
The moisturizing power of formulations containing the catol?, licuri and spent coffee grounds was compared to a placebo formulation and the same formulation containing sweet almond oil (SwA Oil Cream).
 The region selected for the studies was the lower middle portion of the forearms of the volunteers.
The two forearms were subdivided into three regions (16 cm2), where 0.1 g of the formulations containing oils from catol?, licuri, spent coffee grounds, sweet almonds and the placebo formulation were applied, a control area was also evaluated. 
These regions and the formulations applied therein were randomized among the volunteers in order to minimize the differences between the analyses.
The measurements were carried out in an air-conditioned room, with an ambient temperature of 25 ± 2 °C and relative humidity of 50 ± 5%. The volunteers stayed 15 min in this room before the measurements.
The study was submitted and approved by the Research Ethics Committee of the Federal University of Pernambuco/Brazil, under registration N° 167/11—SISNEP FR—417180 and 16847813.7.0000.5208.
For the determination of the immediate effects, the formulations were applied to the forearms of the volunteers, being measured before (baseline) and after 2 h of the single application.
For the long-term study, the volunteers took home the formulations that were applied daily for a period of 20 days. 
The formulations were given to the volunteers in a randomized and anonymous fashion. After 20 days, the volunteers returned to the laboratory to perform new measurements.
The volunteers were adequately instructed in terms of the amount to be applied of each formulation in their specific region.
The water content of the epidermis and transepidermal water loss for all creams was performed with a Corneometer CM 825 and a Tewameter TM300 (Courage and Khazaka Electronic GmbH, Cologne, Germany).
 The measuring principle of the TEWL is based on Fick’s diffusion law, indicating the quantity being transported per area and period of time, the TEWL value is expressed in g/m2h.
 The values of WCE considered are the mean of ten measurements on adjacent sites of the forearm expressed as arbitrary units (UA).
Ten measurements were made in each region of the volunteers’ forearms, and the mean values obtained were calculated.
 The number of measurements made was determined according to the size of the region studied, in order to ensure that the whole site was evaluated.
For the HET-CAM, saline solution (0.9% NaCl w/v) and 0.1 N sodium hydroxide (NaOH) were used as a negative and positive control, respectively. All creams were diluted 1:1 with 0.9% NaCl. 
For each formulation tested, four fresh, fertile Leghorn eggs were used. The eggs were incubated at 37 ± 0.5 °C with a relative humidity of 65 ± 2% for 10 days. 
On the tenth day, the shell membrane was removed, exposing the chorioallantoic membrane (CAM). Visual analysis was used to verify if the CAM was suitable to test, then 300 μL of each formulation was placed on the CAM surface.
 After 20 s, the formulation was removed with saline solution. The CAM was observed under a magnifying glass for 5 min to determine the occurrence of any irritation effects in the CAM blood vessels (vascular lysis, hemorrhage, or coagulation).
 The vascular effects were observed according to the criteria described in the Protocol ICCVAM HET-CAM test method. Each formulation was classified according to the scores: 0–0.99 corresponding to nonirritant; 1.00–4.99 corresponding to slightly irritant; 5.00–8.99 corresponding to moderately irritant (MI); and 9.00–21.00 corresponding to severely irritant (SI) .
The CM-700d Spectrophotometer (Konica Minolta, Tokyo, Japan), using the L*a*b* system color was used to assess the potential irritation of the formulations by verifying possible changes in skin color.
To evaluate the acceptability of all creams, a questionnaire was completed by each volunteer, and assessed sensory attributes such as texture, odor, spreadability, and tackiness using a scale from 1 to 10.
The results are expressed as means ± SD of at least three values. The difference between the measurements was statistically evaluated with the analysis of variance (ANOVA). Data statistical significance was fixed at p < 0.05.
Concerning the macroscopic characteristics, all creams appeared white, glossy, and as semimobile emulsions. 
The pH should ensure the stability of the ingredients of a formulation, their efficacy and safety, as well as being compatible with the intended route of administration. 
The formulations studied had the pH adjusted to slightly acidic values, as this was the ideal pH range (5.5–6.5) for the proposed purposes, and also to optimize the viscosity of the polymer used. 
The formulations showed well-formed droplets with small size variation, thus indicating greater stability of the emulsified system.
The flow curves show that all formulations presented non-Newtonian behavior of the pseudoplastic type, where the viscosity of the fluid decreases with increasing shear rate.
The pseudoplastic behavior presented by all formulations is a desirable feature for emulsions since viscosity values are reduced with increased shear stress, facilitating application to the skin. 
This type of behavior is frequent in formulations containing natural or synthetic gums and polymers.
 Thus, all the creams designed within this work were appropriate for skin application.
The results obtained showed that after two hours of application, the creams containing oils from licuri, catol?, spent coffee grounds, and sweet almonds significantly increase the epidermis water content.
 The effect was more evident for the formulations containing oils from licuri and catol?.
All the formulations studied produced a significant increase in stratum corneum moisture (p < 0.05) 20 days after daily application, when compared with the baseline values and with the placebo cream.
The evaluation of the immediate effects of cosmetic products is important because it allows verification of the action of these products on the skin soon after their application. Likewise, evaluating a dermocosmetic product under the actual conditions of use allows the scientific elucidation of its long-term effects on the skin.
Skin dryness is the most prevalent skin health problem globally and can impact the perception of well-being and quality of life.
 Additionally, dry skin, redness, and cracking may increase the possibility of an infection because the skin barrier is damaged.
 The measurement of hydration in the surface layer of the skin and TEWL gives important information on the biophysical properties and function of the skin barrier.
The WCE results were expressed in arbitrary units and values below 30 represent very dry skin, between 30 and 45, moderately dry skin and values greater than 45, sufficiently hydrated skin.
 Therefore, it is perceived that the use of the formulations containing the oils under study contributed in a significant way to improve the hydration of the skin of the volunteers, who, in general, presented as dry skin.
As know, there is a correlation between stratum corneum (SC) hydration and TEWL values; lower TEWL indicates better skin barrier function.
 In our experiments, all creams containing oils from catol?, licuri and spent coffee grounds increased Corneometer and decreased Tewameter measurements 2 h and 20 days after daily application, suggesting skin hydration.
There was no significant difference between the hydration profiles of the formulations containing the evaluated oils, although their composition is different, licuri and catol? oils have higher percentages of saturated fatty acids, primarily lauric acid. 
The coffee grounds oil has a predominance of unsaturated fatty acids, including 44.7% linoleic acid.
The sweet almond oil was used as a reference, because it has recognized moisturizing and toning properties of dry skin, as confirmed in our study since the cream containing SwA Oil also increased WCE measurements.
Lipids play a significant role in the skin, fatty acids like linoleic, oleic, and lauric acid are naturally present in the skin triglycerides. 
Especially unsaturated fatty acids such as linoleic acid, which has recognized potential in terms of skin hydration by helping to maintain skin elasticity and combat its premature aging.
 However, we can infer that in this case, the improvement on hydration and skin barrier function probably occurred by hindering water permeation through the skin. 
This means spreading an occlusive oily layer onto the stratum corneum surface or by supplementation of skin lipids, and there’s no specific relationship to the fatty acid compositions of each oil.
Previous literature shows that formulations containing oil from spent coffee grounds have multiple skin benefits on barrier function and skin hydration when compared to baseline values, corroborating the results obtained in this study.
The HET-CAM is used to provide qualitative information on the potential effects occurring in the conjunctiva region following exposure to a substance. This assay has been widely used to assess the irritant potential of topical medicines and cosmetics that may come in contact with the eyes.
The results of color variation (a* parameter) did not shown statistically significant alterations (p < 0.05) for any of the tested creams, indicating that they did not promote irritation of the skin during the tests.
According the results of the sensorial evaluation, all creams met consumer appeal and acceptance requirements. 
However, the volunteers could not verify differences between the formulations.
Sensory assessments are important because they show consumers’ perception and acceptability of products. 
The creams presented good acceptability and the volunteers were able to perceive a positive effect in the use of the formulations, however, without differentiating those that contained oil and placebo.
This work showed that all creams containing these oils under study had significant hydration effects on the skin by increasing the water content of epidermis and on skin barrier function, which resulted in TEWL reduction when compared with the placebo and control area, and similar results when compared with formulations containing the positive control.
 This provides a sustainable, cheaper, and effective alternative to the oils of consecrated use in hydration and tonicity of the skin.
In conclusion, these results allow us to signal new vegetable oils with cosmetic applicability to the product chain of natural products with sustainable development.
Aging is a natural and progressive declining physiological process that is influenced by multifactorial aspects and affects individuals’ health in very different ways. 
The skin is one of the major organs in which aging is more evident, as it progressively loses some of its natural functions. 
With the new societal paradigms regarding youth and beauty have emerged new concerns about appearance, encouraging millions of consumers to use cosmetic/personal care products as part of their daily routine. 
Hence, cosmetics have become a global and highly competitive market in a constant state of evolution.
 This industry is highly committed to finding natural sources of functional/bioactive-rich compounds, preferably from sustainable and cheap raw materials, to deliver innovative products and solutions that meet consumers’ expectations. 
Macroalgae are an excellent example of a natural resource that can fit these requirements. 
The incorporation of macroalgae-derived ingredients in cosmetics has been growing, as more and more scientific evidence reports their skin health-promoting effects. 
This review provides an overview on the possible applications of macroalgae as active ingredients for the cosmetic field, highlighting the main compounds responsible for their bioactivity on skin.
The world population continues to grow, although at a slower rate than in the recent past, and is expected to reach 9.7 billion by 2050.
 Globally, demographic projections indicate that life expectancy at birth is increasing, which means that populations are getting older. 
This will certainly have wide-ranging repercussions on social, economic, and health systems.
Aging is a natural and progressive declining physiological process, influenced by multifactorial aspects, that affects individuals’ health in very different ways. 
Oxidative stress has a substantial role in aging, and several studies have suggested different mechanisms by which free radicals can damage biological systems, leading to the development of chronic diseases: diabetes, cognitive decline and neurodegenerative diseases (e.g., Alzheimer’s and Parkinson’s), cardiovascular injuries, skin damage, and certain types of cancer, among many others.
The skin has historically been used for the topical delivery of compounds, being a dynamic, complex, integrated arrangement of cells, tissues, and matrix elements that regulates body heat and water loss, whilst preventing the invasion of toxic substances and microorganisms.
 Structurally, skin is composed of three major regions: epidermis, dermis, and hypodermis. 
According to Mathes et al. , the most superficial layer of the epidermis (stratum corneum) contains a cornified layer of protein-rich dead cells embedded in a lipid matrix which, in turn, manly comprises ceramides, cholesterol, and fatty acids (FA). 
Within the epidermis, melanocytes, Merkel cells, and Langerhans cells can also be found; these are responsible for melanin production, sensorial perception, and immunological defense, respectively.
 The viable epidermis (50–100 μm) containing the basal membrane presents laminins (at least one type), type IV collagen, and nidogen, as well as the proteoglycan perlecan, while in the dermis (1–2 mm) it is possible to find sweat glands and hair follicles.
 The dermis is pervaded by blood and lymph vessels. This skin layer matrix comprises not only arranged collagen fibers and a reticular layer with dense collagen fibers arranged in parallel to the skin surface, but also collagen and elastin, which provide the elastic properties of the skin.
 Fibroblasts are the main cell type of the dermis. Beneath the dermis lies the hypodermis, where adipocytes are the most prominent cell type.
The efficacy of cosmetic active ingredients is related to their diffusion rate through the skin barrier to their specific targets.
 However, small soluble molecules with simultaneous lipophilic and hydrophilic properties have a greater ability to cross the stratum corneum than do high-molecular-weight particles, polymers, or highly lipophilic substances.
 Also, it should be highlighted that the skin surface has long been recognized to be acidic, with a pH of 4.2–5.6, being described as the acid mantle.
During aging, skin becomes thinner, fragile, and progressively loses its natural elasticity and ability to maintain hydration, and with the new society paradigms regarding youth and beauty have emerged new concerns about appearance. 
The use of cosmetic/personal care products (PCP) and their ingredients is part of the daily routine of millions of consumers.
 PCP can be locally applied on the skin, lips, eyes, oral cavity, or mucosa, but systemic exposure to the ingredients cannot be neglected and should be carefully considered. Besides this, there is the possibility of local adverse reactions, such as irritation, sensitization, or photoreactions. 
Given the massive use of these products, they must be diligently evaluated for safety prior to marketing.
According to Regulation European Commission (EC,) 1223/2009, a cosmetic product is defined as “any substance or mixture intended to be placed in contact with the external parts of the human body (epidermis, hair system, nails, lips and external genital organs) or with the teeth and the mucous membranes of the oral cavity with a view exclusively or mainly to cleaning them, perfuming them, changing their appearance, protecting them, keeping them in good condition or correcting body odours”.
However, there is another category—the “cosmeceuticals”—which is attracting the industry’s attention and is of interest to the most attentive consumers. The term has its origin about three decades ago, but to this day it has no legal meaning, namely, under the Federal Food, Drug, and Cosmetic Act.
 Even so, the industry continues to use this designation, and cosmeceuticals’ development and marketing still lies between the individual benefits of cosmetics and pharmaceuticals.
 Recently, Kim stated that some cosmetic formulations, in fact, are intended to prevent disease or to affect human skin’s function or structure, and can be considered as drugs. 
These may include sunscreens or antidandruff shampoos, but also other cosmetics containing active ingredients that promote physiological changes in skin cells, making them appear healthier and younger.
Cosmetics are a global and highly competitive market worth more than €425 billion worldwide.
 In 2016, the European cosmetics and personal care market was the largest in the world, valued at €77 billion in retail sales price, followed by the United States (€64 billion) and Brazil (€24 billion).
In recent decades, consumers have been drawing more and more attention not only to lifestyle issues and their impact on health and well-being, but also to environment and sustainability matters, questioning the origin of products, manufacturing processes, and ecological implications, along with safety issues. 
The search for natural products for a great diversity of purposes, including food, nutraceuticals, cosmetics, and personal hygiene products, among others, somehow reflects these concerns.
 In part, this is due to the consumers’ perception about the safety of botanicals, which are derived from nature, making them desirable ingredients over synthetic ones for a diversity of formulations.
 This is strong encouragement for industry-related research to find solutions and novel/alternative natural raw materials with additional properties that go further than their basic functions (e.g., nutrition).
 Nevertheless, it is of huge importance to guarantee that the selected raw materials are nontoxic and safe, and to also ensure accurate controls throughout all the production phases of industrial batches.
At the end, the main challenge of this whole process is to add value to products. This can be accomplished in several different ways, namely, by finding natural raw materials that are simultaneously rich in functional and bioactive compounds; using these resources in a sustainable way; processing them through green processes and eco-friendly procedures, with low environmental impact; and/or delivering products and innovative solutions that meet consumers’ expectations.
The following sections will provide an overview about the possible application of macroalgae as active ingredients in the cosmetic field, highlighting the main compounds responsible for their bioactivity on skin.
Macroalgae are an excellent example of a natural resource that can fit the above-mentioned principles.
 According to the latest available statistics from FAO (Food and Agriculture Organization), about 23.8 million tons of macroalgae ($6.4 billion) and other algae are harvested annually. The major producing countries are China (54%) and Indonesia (27%), followed by the Philippines (7.4%), Republic of Korea (4.3%), Japan (1.85%), and Malaysia (1.39%). 
In Asian countries, macroalgae are traditionally used as food, for medicinal purposes, or as fertilizers. Besides this, they are a valuable raw material used as an ingredient in animal feed. 
However, some authors consider them to be still underexploited and to have not yet reached their full potential of application.
Overall, following global trends, there is a growing demand for edible algae and algae-based products.
 With aquaculture, which is one of the fastest growing producing sectors, it is possible to considerably increase the availability of that biomass.
The marine environment is extremely demanding, competitive, and aggressive. 
Consequently, marine organisms, including macroalgae, are forced to develop an efficient metabolic response as a self-defense mechanism, for example, by producing secondary metabolites that allow them to preserve their survival and protect themselves against external threats.
 Therefore, sea biodiversity presents the opportunity to explore these molecules and find novel and natural bioactive compounds.
Macroalgae are one of the most ecologically and economically important living resources of the oceans, being generally classified into three groups according to their pigmentation: Phaeophyceae (brown), Rhodophyceae (red), and Chlorophyceae (green).
 Undeniably, they have huge potential as a natural source of important nutrients, namely, fiber (15–76% dry weight, dw), protein (1–50% dw), essential amino acids, essential minerals, and trace elements (ash: 11–55% dw).
 Despite having a low fat content (0.3–5% dw), they provide long-chain polyunsaturated fatty acids from the n-3 family (n-3 LC-PUFA), such as eicosapentaenoic acid (EPA, 20:5n-3), and liposoluble vitamins (e.g., β-carotene, vitamin E).
 However, it is important to highlight that macroalgae development and composition is affected by the species genetics and the surrounding growth conditions, namely, light, temperature, pH, salinity, and nutrient variations.
The production of macroalgae in aquaculture is not very complex and can be performed at a large scale.
 They can develop quickly and, by controlling their growth conditions, it is possible to manipulate their chemical composition, namely, protein, polyphenol, and pigment contents.
Regardless of their origin (either from wild harvest or from controlled production), the overall chemical composition of macroalgae makes them a very worthy bio-sustainable ingredient for a wide range of applications.
 This is of particular interest for the cosmetic industry, in which the ingredients used in the formulations—either active substances, excipients, or additives—are elements of added value and differentiation of a final product. 
The active ingredient is responsible for the cosmetic activity of interest (moisturizing, whitening, antiaging, etc.), while the excipient constitutes the vector for the active ingredient and, in turn, the additive is an ingredient intended to improve the product preservation or its organoleptic properties.
For years, due to their composition, some species of macroalgae have been traditionally used as a source of phycocolloids, namely, agar and carrageenan extracted from red algae such as Gracilaria, Chondrus, Gelidiella, among others, and alginate from brown algae like Ascophyllum, Laminaria, or Sargassum. 
These phycocolloids are water-soluble polysaccharides, mainly used to thicken (increase the viscosity of) aqueous solutions, to make gels of variable degrees of firmness, to produce water-soluble films, and to stabilize some products.
 Agar and carrageenan form thermally reversible gels, while alginate gels do not melt on heating. These compounds are industrially extracted and, due to their technological characteristics, further used as ingredients/additives in a wide variety of products in agro-food, pharmaceutic and cosmetic industries  
Natural plant extracts can be incorporated in a wide variety of cosmetic products, like creams and body lotions, soaps, shampoos, hair conditioners, toothpastes, deodorants, shaving creams, perfumes, and make-up, among others; this has been a very active area of research.
 Regarding, specifically, the use of macroalgae, some species are suitable for dermocosmetic applications.
Within the additives class, preservatives are one of the most representative substances. 
For the industry, finding sources of natural additives as alternatives to current commercial synthetic ones is a matter of great interest.
 Some of the more commonly used additives are BHT (butyl hydroxytoluene) and BHA (butyl hydroxyanisole), used as synthetic antioxidants to retard lipid oxidation.
 However, BHT has been associated with cancer and respiratory and behavioral issues in children. An alternative is to use BHA instead, although, in high doses, it can also be carcinogenic.
 Alternatively, natural antioxidants from plants and macroalgae have been demonstrating a solid substitution potential.
 Their antioxidant-rich extracts actively protect formulations against oil oxidative processes, particularly those containing a higher amount of oily phase, while simultaneously presenting health-promoting effects.
Currently, the interest of the cosmetic industry in macroalgae goes further than just using it as a source of excipients and additives.
 Besides their functional and technological properties, macroalgae are a source of bioactive compounds of added value, which can also be a competitive advantage for this industry.
Over the years, many studies have been conducted about the nutritional composition, secondary metabolites and bioactivities—as well as the potential health-promoting effects—of macroalgae. 
To date, most of these marine-derived compounds were intended for food and pharmaceutical applications.
 Also, several researchers have been exploring the effects of macroalgae on health, showing some progress and important positive outcomes in regards to some types of cancer; heart diseases; thyroid and immune functions; allergy; inflammation; and antioxidant, antibacterial, and antiviral activity, among many others.
Aware of this, the cosmetic industry is interested in using macroalgae as a source of bio-sustainable ingredients since they are extremely rich in biologically active compounds, some of which are already documented as functional active skin care agents.
 As an additional advantage for this industry, these ingredients can be cheap, while matching consumers’ requests for “natural” and “healthier” products.
Some of the bioactive compounds associated with skin care include polysaccharides, proteins, (especially peptides and amino acids), lipids (including PUFA, sterols, and squalene), minerals, and vitamins, but also the secondary metabolites such as phenolic compounds, terpenoids, and halogenated compounds, among others.
 Depending on their physicochemical properties, molecular size, and solubility, bioactive compounds can be extracted, isolated, and purified by several different methods.
 However, in order to be used as ingredients in cosmetics, solvents used in the whole process of extraction must be GRAS-grade (Generally Recognized As Safe), which excludes all of those listed as substances prohibited in cosmetic products, described in Annex II of Regulation (EC) No 1223/2009 of the European Parliament and of the Council of 18 December 2006, concerning cosmetic products. Summarizes some health benefits associated with macroalgae-derived bioactive compounds.
The biological activity of several macroalgae-derived sulphated polysaccharides (SPs) has been often reported.
 The chemical structure of these macromolecules varies according to the species: brown species present mainly laminarans (up to 32%–35% dw) and fucoidans; red algae are mainly rich in carrageenans and porphyrans; and green algae are typically rich in ulvans.
 Anti-proliferative activity in cancer cell lines as well as inhibitory activity against tumors has been described for fucoidans.
 The genus Porphyra contains mainly porphyrans, an agar-like sulphated galactan disaccharide, which accounts for up to 48% of thallus (dw).
 It has been reported that red macroalgae SPs, namely, xylomannan, galactans, and carrageenans, exhibit antiviral activity.
 When accessing the antioxidant activity of different SPs—carrageenans (lambda, kappa, and iota), fucoidans, and fucans—de Souza and colleagues found that fucoidan and lambda carrageenan exhibited the highest antioxidant activity and free radical scavenging activity against superoxide anions and hydroxyl radicals. 
Ulvans, in turn, designated a water-soluble group typically found in green macroalgae, which are mainly composed of glucuronic acid and iduronic acid units together with rhamnose and xylose sulphates.
 It has been reported that these compounds present a high antioxidant capacity against some reactive oxygen species (ROS), namely, superoxide and hydroxyl radicals.
In macroalgae, proteins are a structural part of cell walls, enzymes, and bioactive molecules, such as glycoproteins and pigments.
Protein content is one important parameter when determining the value of biomass, and may be the starting point for selecting species that may be more profitable from which to obtain bioactive peptides and amino acids through selected enzymes. 
The interest in enzymes in the field of cosmetics has increased. Enzymes are highly specific and selective, easy to process, and can be applied in a wide range of substrates and organic transformations in diverse reaction media.
Besides presenting substantial amounts of protein (up to 47% dw), most species present a complete profile of essential amino acids.
 Even so, protein content varies according to species, being generally higher in Rhodophyceae (8%–50% dw), compared with Chlorophyceae and Phaeophyceae. 
Geographical origin and seasonality also affect their protein composition, especially because nitrogen availability may fluctuate due to water temperature and salinity variations, light irradiation, and wave force, thereby affecting their nutrient supply.
Peptides are formed of short chains of 2 to 20 amino acids. Their biofunctional properties depend on their amino acid composition and sequence in the parent protein, which needs to undergo a hydrolysis, commonly with digestive enzymes, so that peptides can be released and become active.
 The biofunctional and bioactive properties of peptides are based on their physiological behavior, which resembles hormones or druglike activities. Besides this, they have the capacity to modify physiological functions, even in the skin, due to their ability to interact with target cells, binding to specific cell receptors or inhibiting enzymatic reactions.
 Marine peptides, including macroalgae-derived ones, have been considered safer than synthetic molecules due to their high bioactivity and biospecificity to targets, with rare adverse effects and reduced risk of unwanted side effects.
 In fact, lately, peptides have been considered a captivating topic in the field of cosmetics and skin applications.
Macroalgae are an excellent source of amino acids and amino acid derivatives, which constitute the natural moisturizing factor (NMF) in the stratum corneum and promote collagen production in the skin.
 Some species of red macroalgae like Palmaria and Porphyra have been reported to present high amounts of arginine in their composition. Arginine is a precursor of urea, which is a component of NMF, used in cosmetic formulations.
Mycosporine-like amino acids are a family of secondary water-soluble metabolites with low molecular weight.
 They are characterized by a cyclohexenone or cyclohexenimine chromophore conjugated with a nitrogen substituent of an amino acid, amino alcohol, or amino group, with maximum absorption wavelengths ranging from 310 to 360 nm. 
Mycosporine-like amino acids protect macroalgae from UV radiation, and have been described as important antioxidant compounds in red algae with reports that they are very efficient photoprotector agents.
 Hence, these metabolites have great potential to be used as natural skin protection ingredients in photo-protective formulations.
Macroalgae are known as a low-energy food, and, although their total lipid contribution is generally very low, their PUFA contents are comparable to or even higher than those found in terrestrial plants.
 Still, the main classes of lipids are present in their composition and include essential FA, triglycerides, phospholipids, glycolipids, sterols, liposoluble vitamins (A, D, E, and K), and carotenoids.
Long-chain PUFAs (LC-PUFAs) have 20 or more carbons with two or more double bonds from the methyl (omega) terminus. 
Marine lipids contain substantial amounts of LC-PUFAs, among which eicosapentaenoic acid (EPA; 20:5n-3) and docosahexaenoic acid (DHA; 22:6n-3) are the most important, along with the precursors α-linolenic acid (ALA; 18:3n-3) and docosapentaenoic acid (22:5n-3).
 Beneficial clinical and nutraceutical applications have been described for these compounds.
LC-PUFAs are essential components of all cell membranes and eicosanoid precursors, and are critical bioregulators of many cellular processes.
 As mediators of many different biochemical pathways, they play an important role in health.
 In several macroalgae species, EPA (C20:5n-3) is frequently the most representative PUFA—in some cases, reaching 50% of the total FA content.
A study performed by Kumari and colleagues reported interesting features when comparing several macroalgae species: Chlorophyta species presented higher C18-PUFAs amounts than did C20-PUF.
As, while the analyzed Rhodophyta species showed the opposite trend.
 In turn, Phaeophyta samples exhibited a C18-PUFAs profile comparable to that of Chlorophyta and a C20-PUFAs profile similar to that of Rhodophyta. Both brown and red species were richer in arachidonic acid and EPA, while the green ones contained higher amounts of DHA.
As stated by several authors, variations in the lipid content and FA composition are often found, and it is generally accepted that such disparities, besides the already mentioned environmental conditions, could be due to different sample treatments and extraction methods.
Macroalgae are a good source of both fat-soluble vitamins (e.g., vitamin E) and water-soluble vitamins, namely, B1 (thiamine), B2 (riboflavin), B3 (niacin), B5 (pantothenic acid), B6 (pyridoxine), B12 (cobalamin), B8 (biotin), B9 (folic acid), and C (ascorbic acid).
 Interestingly, macroalgae are also one of the few vegetable sources of vitamin B12—Its presence is likely due to the bacteria living on their surface or in the proximate waters.
Besides this, macroalgae are important sources of minerals and trace elements, namely, calcium, sodium, potassium, magnesium, iron, copper, iodine, and zinc.
Macroalgae contain a wide variety of pigments that absorb light for photosynthesis, many of which are not found in terrestrial plants. 
Species are characterized by specific sets of pigments. 
Three major classes of photosynthetic pigments are found in algae: chlorophylls, carotenoids (carotenes and xanthophylls), and phycobiliproteins.
 These compounds are responsible for macroalgae color variations during their growth and reproduction cycles, which depend on the amounts of pigments present.
Chlorophylls and carotenoids are liposoluble molecules.
 Chlorophylls, the greenish pigments, are a group of cyclic tetrapyrrolic pigments, with a porphyrin ring with a central magnesium ion and usually a long hydrophobic chain. 
Generally, chlorophyll a is the most abundant photosynthetic pigment, while others are considered accessory pigments.
In turn, carotenoids are polyene hydrocarbons biosynthesized from eight isoprene units (tetraterpenes), usually presenting red, orange, or yellow colorations and remarkable antioxidant properties.
 Within the carotenes group, β-carotene is the most representative one and is present in all classes of macroalgae.
Xanthophylls contain oxygen in the form of hydroxy, epoxy, or oxo groups.
Astaxanthin is a lipophilic carotenoid, structurally similar to β-carotene but with an additional hydroxyl and ketone group on each ionone ring.
 Some studies have reported that astaxanthin can be more effective than β-carotene in preventing lipid peroxidation in solution and various biomembrane systems. 
In turn, fucoxanthin is one of the major xanthophyll pigments in brown algae and is found in edible brown algae, such as Undaria sp., Sargassum sp., Laminaria sp., and Hizikia sp. 
This molecule presents a unique structure including allenic, conjugated carbonyl, epoxide, and acetyl groups, and was recently identified as the major bioactive antioxidant carotenoid in 30 Hawaiian macroalgae species.
Phycobiliproteins (PBP) are a water-soluble group of photosynthetic pigments comprising different compounds, like phycoerythrins with a red pigment linked to the protein molecule, or phycocianins with a blue pigment instead.
 These different molecules absorb at different wavelengths of the spectrum, which makes them very colorful and highly fluorescent in vivo and in vitro. 
This is of special interest for biotechnological applications, where they are useful in diverse biomedical diagnostic systems.
 Some have been used as natural food colorants, as well as pink and purple dyes in lipsticks, eyeliner, and other cosmetic formulations.
 Being water-soluble molecules, it is possible to extract PBP from algal tissues using green extraction solvents, like water or buffers.
In macroalgae, phenolic compounds are secondary metabolites, which means that they do not directly intervene in primary metabolic processes such as photosynthesis, cell division, or reproduction.
 Instead, it is believed that this class of compounds is mainly responsible for protection mechanisms, namely, against oxidative stress or UV cytotoxic effects.
Phlorotannins, a subgroup of tannins mainly found in brown macroalgae and, to a lesser extent, in red species, are derived from phloroglucinol units, whereas in plants polyphenols are derived from gallic and ellagic acids.
 Phlorotannins are highly hydrophilic compounds with a wide range of molecular sizes (from 126 Da to 650 kDa), and are of interest for different applications (e.g., nutritional supplements, cosmetic and cosmeceutical products).
Many external factors, including UV radiation, climate conditions, and air/environmental pollutants (e.g., tobacco smoke) can affect the protective ability of skin and promote its premature aging. 
Commonly, this continuous exposure leads to oxidative stress caused by the imbalance between oxidants and antioxidants, which affects skin health. 
Skin aging produces several changes: it becomes thinner, more fragile, and progressively loses its natural elasticity and ability to maintain hydration.
In cosmetic formulations, the primary functions of natural ingredients may be antioxidant, collagen boosting, or even anti-inflammatory.
 The incorporation of macroalgae-derived bioactive compounds in cosmetics has been growing as more and more scientific evidence is documented in regards to their health-promoting and anti-pollution effects.
 The foremost interesting classes of bioactive compounds include those intended for antiaging care, including protection against free radicals, prevention of skin flaccidity and wrinkles, anti-photoaging, photoprotection against UV radiation, moisturizing, and skin whitening.
In biological systems, oxygen is the most common generator of free radicals—highly reactive molecules with harmful potential. ROS and reactive nitrogen species (RNS, such as nitric oxide, NO?) are products of normal cellular metabolism. 
They act as secondary messengers by regulating several normal physiological functions. However, they can play a dual role, as they can act as both damaging and beneficial species. 
Oxidative stress, caused by an overproduction of ROS, can induce serious damages in several cell structures (lipids and membranes, proteins, and DNA). At the same time, ROS and RNS also participate in several redox regulatory mechanisms of cells in order to protect them against oxidative stress and maintain their “redox homeostasis”.
A great diversity of bioactive compounds, namely vitamin E, vitamin C, superoxide dismutase, coenzyme Q10, zinc sulphate, ferulic acid, polyphenols, and carotenoids, among others, have been successfully used, for a long time, in cosmetic products as free-radical-scavenging molecules.
An in vitro study showed that an algal extract containing astaxanthin presented a protective effect in the reduction of DNA damage and maintenance of cellular antioxidant status in lines of human skin fibroblasts (1BR-3), human melanocytes (HEMAc), and human intestinal Caco-2 cells, irradiated with UVA.
In the last few years, other classes of macroalgae compounds have been showing potential as bioactive ingredients for cosmetics.
 In a study performed with Ecklonia cava, crude polysaccharide and polyphenolic fractions obtained by a former enzymatic hydrolysis were evaluated, showing a suppressive effect on tumor cell growth, and antioxidant and radical scavenging activities in different cell lines, with low toxicity.
 In another study, Zhang and colleagues evaluated the antioxidant activity of SPs extracted from five macroalgae—one brown (Laminaria japonica), one red (Porphyra haitanensis), and three green species (Ulva pertusa, Enteromorpha linza and Bryopsis plumose)—reporting that their antioxidant behavior depended on the type of polysaccharides of each extract, which was shown to be different among the species.
Likewise, protein hydrolysates, peptides, or amino acids from macroalgae can play a substantial antioxidant role in a diverse range of oxidative processes.
Moisturizing and hydration are crucial for skin care and are essential to maintaining its healthy appearance and elasticity, while also strengthening its role as a barrier to harmful environmental factors.
 Approximately 60% of the epidermis is water which is fixed by hygroscopic substances known by the generic name of NMF (natural moisturizing factor). NMF constitution includes amino acids (40%), including serine (20–30%), lactic acid (12%), pyrrolidone carboxylic acid (12%), urea (8%), sugars, minerals, and a fraction that still remains undetermined.
 Topical application of the above-mentioned components, which can act as humectants, can improve the skin moisturizing ability and relieve a dry skin condition.
Polysaccharides play a very important role in cosmetic formulations as humectants and moisturizers.
 These macromolecules have a high capacity for water storage and can be linked to keratin through hydrogen bonds, thus improving skin moisturization.
 According to Wang and colleagues, polysaccharides extracted from Saccharina japonica revealed better moisturizing properties than hyaluronic acid, suggesting that these polysaccharides could be an interesting ingredient for cosmetics.
 The authors also found that the sulphated group was a main active site for moisture absorption and moisture retention ability, and that the lower-molecular-weight polysaccharides presented the highest moisture absorption and moisture retention abilities.
 A cosmetic formulation containing 5–10% extract of Laminaria japonica improved skin moisture in a group of volunteers.
 Authors suggest that two mechanisms might be responsible for these promising results: on the one hand, the hydroscopic substances of the extract  may contribute to reinforcing the NMF in skin, helping to retain appropriate moisture levels in the epidermis; on the other hand, phycocolloids, like alginate, and protein in extracts attach to skin proteins to form a protective barrier for moisture loss regulation.
With aging, the extracellular tissue matrix components—collagen, hyaluronic acid, and elastin, among others—decrease, leading to thinner skin with a weakened structure.
 However, some active ingredients have been showing promising results in reverting these signs.
 For instance, some peptides have been used as cosmeceutical ingredients showing interesting antiaging effects, namely in wrinkle and fine line reduction, and in skin firming and skin whitening.
 Different types of peptides and mechanisms of action are responsible for those effects. Signal peptides, for instance, stimulate ETM production by specifically increasing neocollagenesis.
 Besides this, they can also promote fibronectin and elastin synthesis, as well as cell–cell cohesion, with results in skin firming and wrinkle and fine line reduction.
 Therefore, the use of formulations containing these compounds can promote the replacement of the lost extracellular tissue matrix, reducing, then, the appearance of wrinkles.
Marine-derived phlorotannins, extracted from Eisenia bicyclis and Ecklonia kurome, presented a strong hyaluronidase inhibitory effect in in vitro assays, showing potential as a bioactive ingredient to recover ETM functions.
Sunlight UV radiation is still the most powerful environmental risk factor in skin cancer pathogenesis. 
The use of photoprotective products with UV filters is extensively recommended to prevent (and protect the skin from) several types of damage, like sunburn, photo-aging, photodermatoses, or even skin cancer.
 Within this type of product, formulations containing sun-screening agents combined with antioxidants are considered to be safer and more effective.
Bioactive compounds able to absorb UV radiation can protect human fibroblast cells from UV-induced cell death and suppress UV-induced aging in human skin.
As previously mentioned, macroalgae have developed mechanisms to prevent damage from UVB and UVA radiations, either by producing screen pigments, like carotenoids, or by phenolics.
Heo and Jeon reported that fucoxantin from Sargassum siliquastrum presented a great in vitro ability to protect human fibroblasts against oxidative stress induced by UVB radiation. 
Another study with Halidrys siliquosa (Phaeophyta) showed that the tested extracts presented strong antioxidant activity and a good sunscreen potential, associated with the presence of phlorotannins like diphlorethols, triphlorethols, trifuhalols, and tetrafuhalols.
Melanin, which is the main determinant of skin color, absorbs UV radiation and prevents free radical generation, protecting skin from sun damage and aging.
 However, the abnormal production of melanin can be a dermatological condition and a serious cosmetic issue.
Tyrosinase catalyzes melanin synthesis in two different pathways: the hydroxylation of L-tyrosine to 3,4-dihydroxy-l-phenylalanine (L-dopa) and the oxidation of L-dopa to dopaquinone, followed by further conversion to melanin.
 It is possible to regulate melanin biosynthesis, for instance, by protecting skin and avoiding UV exposure, or by inhibiting tyrosinase action or melanocyte metabolism and proliferation.
The demand for natural products that inhibit/control or prevent melanogenesis and, consequently, skin pigmentation, is growing all over the world, especially for melanin hyperpigmentation dermatological diseases, as well as for cosmetic formulations for depigmentation. 
Recently, macroalgae extracts showed profound inhibitory effects against tyrosinase and melanin synthesis in both in vitro cell experiments and an in vivo zebrafish animal model.
An inflammatory process causes oxidative stress and reduces cellular antioxidant capacity. The large amount of produced free radicals react with FA and proteins of cell membranes, permanently damaging their normal functions.
Senevirathne and colleagues evaluated antioxidant and anticholinesterase (AChE) activities, as well as the protective effects of enzymatic extracts from Porphyra tenera against lipopolysaccharides (LPS)-induced nitrite production in RAW264.7 macrophage cells.
 The authors concluded that all enzymatic extracts showed no cell cytotoxicity (cell viabilities greater than 90% in all cases), and all enzymatic extracts effectively inhibited LPS-induced nitric oxide production in RAW264.7 macrophages. 
These results indicate that Porphyra tenera could be a valuable source of natural antioxidants and anti-inflammatory ingredients for cosmetic purposes.
Although cellulite is not a pathological condition, it remains a matter of cosmetic concern, especially for postadolescent women. 
Many efforts have been made to find treatments that improve symptoms and signs of cellulite, as well as the visual appearance of skin.
Al-Bader and colleagues tested a formulation containing aqueous extracts of Furcellaria lumbricalis and Fucus vesiculosus to assess in vitro lipolysis in mature adipocytes and measured pro-collagen I in human primary fibroblasts, finding that there was an improvement of lipolysis-related mechanisms and pro-collagen I production.
 Subsequently, they evaluated cellulite by dermatological grading and ultrasound measurements and could observe a clinical improvement in the cellulite.
Macroalgae extracts may also be of interest for slimming purposes, as evidence demonstrates that they significantly decrease the body weight gain, fat-pad weight, and serum and hepatic lipid levels in high-fat-diet-induced Sprague Dawley male obese rats, and showed a protective effect against these factors through the regulation of gene and protein expression involved in lipolysis and lipogenesis.
Thyroid hormones are involved in mechanisms that increase the synthesis of carnitine palmitoyl transferase which, in turn, promote lipolysis by increasing the penetration of fatty acids in the mitochondria.
 Diet is the major contributor of iodine, but breathing gaseous iodine in the air and placing it on the skin are other possible paths.
 Fucus serratus L. is a rich source of iodine. A recent in vivo study reported that bath thalassotherapy with this macroalgae had the potential to increase the urinary iodide concentration of the bather, indicating inhalation of volatile iodine as the predominant route of uptake.
 Another in vivo study also showed the effectiveness of a cosmetic product containing extracts of Gelidium cartilagineum, Pelvetia canaliculata, and Laminaria digitata, as well as other active ingredients, in exerting a slimming effect, compared with a placebo.
An enzyme-assisted extraction enabled a more effective obtention of proteins, neutral sugars, uronic acids, and sulphate groups in three species of macroalgae: the red Solieria chordalis, the green Ulva sp., and the brown Sargassum muticum. In this study, although no cytotoxicity was observed for all extracts, only S. chordalis presented good antiherpetic activities, mainly attributed to its richness in sulphate groups.
An O/W (oil in water) emulsion prepared with a phlorotannin-enriched fraction obtained from the brown macroalgae Halidrys siliquosa presented antibacterial capacity against Pseudomonas aeruginosa, Staphylococcus aureus, and Escherichia coli.
 Another study with a red macroalgae (Pterocladia capillacea) revealed that using carbohydrate degrading enzymes prior to in vitro assays produced extracts with higher antioxidant capacity and stronger antibacterial effect against Escherichia coli and Staphylococcus aureus.
 This could be of particular interest for the development of natural preservatives to be used in cosmetic formulations.
Macroalgae-derived ingredients have been used in cosmetic formulations due to their technological properties. 
However, it is well established that the interest of the cosmetic industry in macroalgae goes further than just using it as a source of excipients and technological additives. 
Macroalgae are a source of added-value compounds, with scientific evidence showing their benefits for human health and wellbeing. This can be a competitive advantage for this industry, namely in terms of finding and using novel molecules and agents that apparently have biological effects on skin, such as antiaging, antioxidant, moisturizing, collagen-boosting, photo-protective, whitening and melanin-inhibiting, anti-inflammatory, anti-cellulite and slimming, and antiviral and antibacterial activities. 
This review has summarized some of the possible applications of macroalgae as active ingredients in the cosmetic field, highlighting the main compounds responsible for their bioactivity on skin.
Sunscreens are the most common products used for skin protection against the harmful effects of ultraviolet radiation. 
However, as frequent application is recommended, the use of large amount of sunscreens could reflect in possible systemic absorption and since these preparations are often applied on large skin areas, even low penetration rates can cause a significant amount of sunscreen to enter the body.
 An ideal sunscreen should have a high substantivity and should neither penetrate the viable epidermis, the dermis and the systemic circulation, nor in hair follicle.
 The research of methods to assess the degree of penetration of solar filters into the skin is nowadays even more important than in the past, due to the widespread use of nanomaterials and the new discoveries in cosmetic formulation technology.
 In the present paper, different in vitro studies, published in the last five years, have been reviewed, in order to focus the attention on the different methodological approaches employed to effectively assess the skin permeation and retention of sunscreens.
The detrimental effects of human exposure to ultraviolet (UV) radiation have been widely investigated and can be immediate, as in the case of sunburns, or long-term, causing, in most cases, the formation of oxidizing species responsible of photo-aging, immunosuppression and chronic effects such as photo carcinogenicity.
 Ultraviolet radiation of sunlight consists of UVA (315–400 nm), UVB (280–315 nm) and UVC (100–280 nm) radiations, depending on the wavelength.
 Whereas the stratospheric ozone layer completely blocks UVC radiation and UVB wavelengths below 295 nm, 90–95% of the UV radiation that reaches the Earth’s surface is UVA, with UVB accounting for most of the remainder.
 At longer wavelengths, UVA penetrates deeply through the skin layers, reaching the basal layer of the epidermis and the inner dermis, interacting with endogenous and exogenous photosensitizers and generating reactive oxygen species (ROS), which are responsible for the onset of DNA mutations related to skin cancer development, of the acceleration of collagen breakdown and of the decrease of collagen synthesis, with consequent appearance of skin fragility and wrinkles.
Sunscreens are the most common products used for skin protection against the harmful effects of ultraviolet radiation; they should provide broad-spectrum UV protection for the presence of active ingredients, which attenuate the transmission of UV radiation onto the skin by absorbing, reflecting or scattering the incident radiation.
 It is not infrequent to see different types of molecules contemporaneously present in commercially available formulations, used in combination because none of them is individually able to provide broad spectrum UVA-UVB protection.
 The active molecules could be classified as either “chemical” or “physical” based on their mechanism of action: In chemical sunscreens, the active ingredient is an organic compound, with aromatic structure, that works by absorbing UV radiation and dissipating the energy as heat or light; in physical sunscreens, the active ingredient is an inorganic compound that acts by physically reflecting or scattering the UV radiation.
 Recent advances in nanotechnology have led to the production of nano-sized particles of these metal oxides, whose ability to absorb UV radiation is increased with respect to micronized ones.
 Unfortunately, TiO2 and ZnO nanoparticles, in addition to being effective sunblock and eliminating the anaesthetic formation of an opaque film on the skin (due to visible light scattering), seem to possess a photocatalytic activity associated with oxidative stress and genotoxicity.
 Moreover, as frequent application and reapplication after contact to water are recommended, the use of large amount of sunscreens could reflect in possible systemic absorption.
 Since these preparations are often applied on large skin areas, even low penetration rates can cause significant amount of sunscreen to enter the body.
 As the site of action of sunscreens is restricted to the skin surface or to the uppermost part of the stratum corneum, they should not penetrate into the viable epidermis, the dermis and into the systemic circulation; furthermore, the follicular uptake should be avoided, in order to not penetrate human cells where they can cause deleterious DNA damages.
 This can happen when the solar-filter has a high substantivity, intended as the capacity of adhering to and of being retained by the skin, thus resisting removal by bathing or perspiration.
The degree of penetration depends strongly on the physico-chemical properties of the active compound, the nature of the vehicle in which the sunscreen is formulated and several factors related to the skin.
 Indeed, both molecular weight and lipophilicity of the molecule play an important role in cutaneous penetration, as well as it has been demonstrated that skin permeation and retention from topical products can differ significantly among the formulations used.
Traditionally, in vitro percutaneous absorption studies have been carried out using animal skin or excised human skin from cosmetic surgery or autopsy. 
However, various three-dimensional cultures of human skin epithelial cells, simulating the native multilayer tissue architecture, are nowadays commercially available.
In the present paper, different in vitro studies, published in the last five years, have been reviewed, in order to focus the attention on the different methodological approaches employed to effectively assess the skin permeation and retention of sunscreens in the light of the entry into force of the EU Cosmetic Regulation with the ban of animal testing for cosmetic purposes, as well as the widespread use of nanomaterials and the new discoveries in cosmetic formulation technology.
Organic filters are molecules with aromatic structure having a carboxyl group that undergoes isomerization under the influence of energy absorbed from radiation. 
Their efficacy is mainly due to the physico-chemical properties, such as absorption coefficient and absorption spectra.
Butyl methoxy dibenzoyl methane (avobenzone, AVO) is among the most common UV filters present on the market, due to the broad absorption spectrum in the UVA region.
 However, it suffers photo-degradation, giving rise to new compounds responsible of photoallergic and phototoxic reactions.
 Therefore, the maximum concentration in ready to use preparation is fixed at 5%.
Diethylamino hydroxybenzoyl hexyl benzoate (DHHB) is an effective UVA filter, with high compatibility with other sunscreens and it is used in solar products at a maximum concentration of 10%.
Compounds from the group of camphor are characterized by high photo-stability and rarely are cause of allergic manifestations.
 Among them, 4-methylbenzylidene camphor (4-MBC) is authorized in Europe at the maximum concentration of 4%.
A recently approved chemical compound for use in cosmetic products is 2-cyano-3,3-diphenyl acrylic acid 2-ethylhexyl ester (octocrylene, OCT), absorbing UVB radiation at 303 nm wavelength and which maximum authorized concentration is 10% as acid form.
Isoamyl p-methoxycinnamate (IPMC, amiloxate), liquid at room temperature, is an efficient UVB absorber. 
It is a lipophilic molecule and the maximum amount that can be used in topical formulations is 10%.
Ethylhexyl triazone (ETZ) possesses an excellent photostability and, thanks to its water insolubility, is often used in water resistant products.
 The very high extinction coefficient and the high molecular weight make it a very efficient solar filter.
 The FDA does not approve its use in sunscreen products, while in Europe, it is allowed at maximum concentration of 5%.
A derivative of the once-popular PABA sunscreen ingredient, ethylhexyl dimethyl PABA (Padimate O), is among the most potent UV-B absorbers.
 The decline in its use, along with the demand for higher sun protection factor (SPF) products, have led to the incorporation of multiple active ingredients into a single product to achieve the desired SPF, replacing single PABA esters.
 It is suspected to release free radicals, causing indirect DNA damage, to possess estrogenic activity, and to cause allergic reactions; the maximum allowed concentration is 8%.
Ethylhexyl methoxycinnamate (octinoxate, OMC) is one of the most commonly used UVB filters in sunscreen products, due to its high absorption capacity in the shorter wavelength region (290–320 nm).
 Its safety profile has been, firstly, reviewed by the SCC (SPC/1037/93, S28) in 1993. 
 The maximum authorized concentration in sunscreen products is 10%.
A solid type UVA-UVB filter is represented by 2-hydroxy-4-methoxybenzophenone (oxybenzone, benzophenone-3, BP-3), a common ingredient in commercial sunscreens, thanks to the broad absorption bands in the UVA (400–315 nm), UVB (315–280 nm) and UVC (280–100 nm) regions, and therefore suitable to absorb incident solar radiation (UVA and UVB) and artificial UV sources (UVC). Although it remains photostable after being irradiated for many hours, some controversies regarding its ability to affect endocrine system and to cause dermatological problems are still ongoing.
 In Europe, as of September 2017, the use BP-3 is allowed as a UV-filter up to 6% in cosmetic sunscreen products and up to 0.5% in all types of cosmetic products to protect the formulation.
 Moreover, the consumers must be warned that the formulation contains BP-3 due to allergenic and photoallergenic potential.
A recent strategy to reduce cutaneous absorption of sunscreen is the use of high molecular weight UV-filters, such as bis-ethylhexyloxyphenol methoxyphenol triazine (bemotrizinol, BMZ), one of the few chemical sunscreens with good coverage in both the UVA and UVB range.
 It is a new oil-soluble filter with broad-spectrum protection and high efficacy, which does not degrade under sunlight; its photostability and compatibility with many other products allow it to be used in cosmetic formulations to protect less photostable UV filters, such as AVO.
Phenylbenzimidazole sulfonic acid is a chemical sunscreen agent that absorbs primarily UVB radiation. It provides some protection against short UVA (UVA-2) but cannot be considered a comprehensive UVA blocker.
 It is used as an UV-filter in cosmetic products at a maximum concentration at 8%.
 The booster effect on the body natural reserve of antioxidants can contribute to neutralization of intrinsic and extrinsic ROS, creating a new kind of sunscreen with a two-step protection: The first operated by UV-filters as a “passive” protection by absorbing and reflecting UV radiation and the second as “active” protection by antioxidants quenching ROS generated by UV light that has by-passed UV filters.
 Differently from synthetic UV-filters, which have to remain on the stratum corneum to be safe and effective, natural compounds should reach the viable skin layers to exploit photo-protection effect, since ultraviolet radiation penetrates deeply the skin.
Among the naturally occurring polyphenols, one of the most investigated products is trans-resveratrol, which possesses antioxidant, anti-inflammatory and anti-tumoral properties, as widely reported.
 It has also been demonstrated that it is able to inhibit UVB induced inflammation and lipid peroxidation of the skin following topical application.
The well known carotenoid β-carotene possesses skin protective effects against UV and IR radiation and if applied prior to irradiation is able to protect skin from UVA induced oxidative stress.
Inorganic filters are inert and non-irritant substances, able to protect the skin from the incident solar radiation due to physical phenomena, such as scattering and reflection, by forming a layer over the skin that works as mechanical barrier.
 Notwithstanding the physical filters on the market are very few with respect to the chemicals, they possess many advantages, as high photo-protection level in the longer UVA range, photostability and low photoallergic potential. 
The most investigated inorganic UV filters are zinc oxide (ZnO) and titanium dioxide (TiO2).
Available literature data on skin permeation and penetration of nanomaterials should be deeply evaluated in order to perform a risk evaluation of these relatively new kinds of materials. 
Despite the relevant scientific data on this topic, there is still the need to provide a definite safety profile related to nanoparticles skin exposure. 
Indeed, notwithstanding the stratum corneum represents the outermost barrier for penetration of exogenous substances, it has to be taken into account that this layer could undergo impairment or disruption upon treatments or age related mechanisms; it is also well known that skin diseases, such as contact dermatitis or erythema, can cause an increase in skin permeability.
 Moreover, during the last years, the trans-appendageal route (diffusion through the hair follicle and sweat gland) has gained importance, as either potential target site or shunt for delivery of various molecules.
 Therefore, the first point to clarify is the mechanism of nanoparticles penetration through the skin. 
Many authors proposed nanoparticles storage in the skin lipid matrix between corneocytes or in the appendages, from where they are released in a controlled and prolonged manner.
 On these bases, it is fundamental to further investigate how nanoparticles size, shape, surface chemistry and charge can affect skin penetration, also in relation to other physical factors concerning the environmental media.
 A significant point to take into account is that in vitro alternative methods to animal testing have not yet been validated for nanomaterials, representing an obstacle to the safety assessment of these cosmetics ingredients in the European market. Anyway, given the importance of the subject and the wide literature on it, it was necessary to mention the subject, but it will not be discussed in this review.
In vitro studies on sunscreens published from 2013 to 2017 have been reviewed in order to focus on the assessment of the permeation/penetration profile of the molecules not in their nano-form.
 It is a consolidated opinion that in vitro tests on the skin, using Franz cells and similar techniques, allow to obtain important information on penetration pathways, in order to ensure that the investigated molecules are effective and their residence time in the skin is adequate to assure UV protection. 
These methodologies are considered a reliable model to investigate skin diffusion, even though what happens in real condition can be underestimated. 
Indeed, in real condition skin permeation could be increased when superficial impairment or skin flexion happened as well as for active transportation .
Some controversies have been occurred regarding the skin models to be employed during permeation/penetration studies, in order to select the most appropriate to resemble human in vivo conditions.
 As reported in OECD guidelines for the testing of chemicals, skin from human or animal sources can be used, as either epidermal membranes or dermatomed skin at different thickness. 
During the last years, different kinds of skin have been investigated, on the general principle that rats’ and rabbits’ one is more permeable than that of humans, while the skin permeability of pigs is more similar.
 Anyway, the selection of one species rather than another, the anatomical site and the preparative technique must be justified in performing in vitro tests. 
Full thickness skin, dermatomed at a constant depth, is the preponderant choice for in vitro permeation/penetration tests; some authors decided to use human abdominal epidermal membranes, removed from the dermis with a scalpel blade, dried and stored at 4 °C before experiments.
 The choice of stratum corneum-epidermis membrane instead of full thickness skin was justified since the dermis could act as a further barrier to permeation, distorting in vitro evidence.
Analysis of recent literature shows an increasing use of porcine skin with respect to the past.
 Most of the studies employed the outer surface of freshly excised pig ears, after hair and underlying cartilage removal.
 The skin was often dermatomed to reduce its thickness and stored at ?20 °C/?80 °C for a maximum period of 30 days before use. 
Different receptor media were chosen, depending on the solar filter investigated and considering the very low water solubility of these molecules and their generally high lipophilicity.
 The choice of an appropriate receiving phase is determinant for these studies, especially when lipophilic molecules are investigated, as it can lead to false conclusions linked to insufficient solubility of UV-filters.
 Moreover, it has to be taken into consideration that the receptor fluid chosen should not alter the barrier properties of the skin.
 In case of studies on BP-3, the receptor medium used consisted of phosphate buffer solution (pH 7.2, 150 mM) added of either albumin or 0.5% Tween 80 to ensure BP-3 solubility.
 In another study, a phosphate buffer (pH 7.4, 100 mM) containing 4% w/v bovine serum albumin (BSA), for its ability in solubilizing lipophilic molecules, represented the receiving phase when the behaviour of different solar-filters (BMZ, OMC, AVO, OCT) after cutaneous application of an O/W emulsion had been investigated.
In most cases, the permeation experiments lasted 12–24 h and, after this time, the amount of active ingredient distributed in the different skin layers was evaluated by removing SC with 15–20 subsequent tape-strips and by mechanically separating epidermis (E) and dermis (D).
 In all reported cases, the samples were analyzed by high performance liquid chromatography after opportune extraction treatment from the biological matrix to quantify the amount of solar-filter in the receiving fluid and the skin portions.
It was found that BP-3, with a relatively low molecular weight and a log P of 3.58, had itself a good ability to permeate and penetrate the skin.
 OMC, AVO, OCT and BMZ that possess the log P of 5.96, 4.51, 6.78 and 12.6, respectively, indicative of a high lipophilicity, was retained over 90% in the SC while the permeated amounts were below LLOQ.
 Due to these characteristics, they seem able to accumulate into the lipid phases of the stratum corneum, producing a kind of reservoir, while they appear to have difficulty in penetrating the viable epidermis, layer of predominantly hydrophilic nature.
Shokri et al. investigated the fate of AVO, BP-3 and ESZ formulated in a cosmetic O/W emulsion as free filters or included in a complex with β-cyclodextrin in permeation studies through abdominal skin of Wistar rats, which were shaved with razors 24 h prior of the experiments.
 It is necessary to emphasize that these products are among the most common UV filters on the market and that, after cutaneous application, in vivo have been demonstrated to permeate the skin in significant amounts.
The receptor phase was based on phosphate isotonic buffer pH 7.4 and isopropanol 70:30 v/v to favour sunscreens solubility.
 The quantitative determination was performed by high performance liquid chromatography (HPLC). It was found that ESZ, when applied on the skin free or included in the cyclodextrin complex, was able to permeate the rat skin in a higher amount than BP-3 and AVO. 
In all cases, the complexation not only reduced the amount of permeated agent, but also prolonged the lag time of permeation.
 It is important to highlight the different behavior of the filters in relationship with their chemical–physical characteristics. 
In fact, both BP-3 and AVO exhibited a moderate lipophilicity and a low molecular weight, which allow the transit through the stratum corneum, but hinder a high penetration in the more hydrophilic viable epidermis and dermis.
 However, ESZ possesses a log P of ?1.1/?2.1 and a comparable molecular weight with respect to the other filters. 
On this basis, it seems that the ESZ dimension are somewhat responsible of its penetration through the stratum corneum, while the hydrophilic character allow a high flux through the skin.
By comparing the results obtained from the above mentioned permeation studies through different skin models, it is clear that free BP-3 applied in O/W emulsion was able, in every case, to permeate the skin and showed the same flux through both pig and rat skin, while the time to saturate the membrane was higher in case of pig skin. 
Conversely, the more lipophilic AVO did not permeate the pigskin, while it was found in appreciable amounts in the receiving phase of permeation studies through rat skin. 
Such results confirm what is already known from previous studies, suggesting that rat skin is generally more permeable than pigskin towards permeants with different physicochemical properties and in particular for the more lipophilic ones.
 Indeed, both the composition and packing of stratum corneum lipids, known to be key factors of skin permeability, differ between rodent and pigskin.
Most researchers are employing intact skin for the permeation/penetration studies, without taking into account that aging processes, diseases and sun exposure could often alter the skin structure. 
As some permeants could overcome a compromized barrier and penetrate through skin by inducing toxicity, it would represent an interesting tool to evaluate percutaneous absorption of solar filters through altered skin. 
Such an experiment was performed by Hung et al., which used nude mice aged eight and 24 weeks as animal model for young and senescent skin in order to mimic chrono-aging. 
The use of nude mouse was justified since it has been reported an identical histology and biochemistry to human skin in photoaging studies; even though it is notably more permeable, the mouse skin could be a useful model of facial skin on which the filters are applied, legitimizing the use of mouse skin in this kind of experiment.
 Moreover, they irradiated the dorsal skin of the mouse with UVA (365 nm, 10 J/cm2) every other day for three days and with UVB (312 nm, 175 mJ/cm2) once a day for five days, at a distance of 10 cm for a period of 100 min and 1 min for UVA and UVB, respectively, in order to induce skin photo-aging. 
A combination of the two was also carried out to simulate UVA + UVB radiation. 
The skin absorption and follicular uptake of AVO and BP-3 as chemical sunscreens and of ZnO as physical sunscreen were evaluated by performing a permeation experiment with Franz vertical diffusion cells followed by the differential stripping technique from aqueous vehicles containing the solar filters.
 The experimental conditions were set with a receiving phase consisting of 30% ethanol/pH 7.4 buffer, a temperature of 37 °C and an experiment length of 24 h. To completely remove the stratum corneum from the skin, at the end of the permeation experiment, 20-tape strips were performed, followed by cyanoacrylate casting to extract the hair follicle.
 It was found that ZnO, both in the micronized and nano-form, was not able to penetrate into the skin or the receptor, regardless of the treatment used. 
The behavior of BP-3 was not affected by chrono-aged skin, while irradiation, in particular UVA and UVA + UVB, increased both the permeation and the deposition of the filter in the follicle. BP-3 has been shown to penetrate skin and reach the circulation, phenomenon that appears more severe when the skin is irradiated with UV light. 
On the contrary, regarding the more lipophilic AVO, senescent skin showed less deposition with respect to young skin, probably due to lower sebum distribution in aged skin; the follicular uptake in senescent skin was increased by UVA or UVA + UVB radiation, thus reaching the same values of young skin. 
In any case, AVO was able to permeate the skin, maybe due to its high affinity for stratum corneum. The application of AVO and ZnO to photoaged skin may not increase the risk of excessive absorption; besides, when the skin is naturally aged the skin penetration of AVO is even reduced.
As stated above, many studies investigating the fate of UV filters after cutaneous application performed sequential tape stripping in order to evaluate the amount of the molecule penetrated in the stratum corneum. 
The evaluation of drug penetration into the stratum corneum (SC) by tape stripping requires an accurate measure of the amount of SC on each tape-strip in order to determine the stratum corneum depth. 
Recent studies are applying infrared densitometry (IR-D) to in vitro tape stripping using SquameScanTM 850A to verify the endpoint of tape-stripping, i.e., complete SC removal. 
In fact, the SC depth can be extrapolated from the IR-D data of sequential tape-strips, where the protein content of each tape strip can be indirectly quantified from the tape absorbance; the lower limit of quantification of IR-D indicates the complete removal of the SC (less than 5% of the total SC remaining) and can be used to know the exact numbers of tapes needed.
 The IR-D technique allowed the authors to affirm that the UV absorbing molecules were largely distributed in the first 1.7 μm of the SC, with smaller amounts accounting for the other 3.8 μm, confirming only superficial penetration of these materials as for their intended use.
Among all the papers reviewed, only the study performed by Monti and colleagues used a reconstructed human epidermis model from normal human keratinocytes (Episkin, SkinEthic Laboratories, Lyon Cedex 7, France) as substrate for the permeation/penetration studies; this model is histologically similar to the native human epidermis. 
Episkin was placed between on the donor and receiving chambers of a Harvard apparatus, equipped with six thermostated cells.
 The receiving phase consisted of pH 7.4 phosphate buffer solution (PBS) added with 1.0% Brij 98 to increase the solubility of the sunscreen under study, 4-MBC. 
To assess the distribution profile of the solar filter in the skin, the tape-stripping technique was employed.
 As the tissue was constituted only of the epidermis without dermis, two tape strips were performed and the remaining tissue was considered as the living epidermis. 
In order to quantify the degree of skin penetration of 4-MBC, an extraction procedure from the tissues was performed and the samples were analyzed by HPLC. 
Since the Cosmetic Regulation 1223/2009 have banned the use of experimental animals for testing cosmetic products and there are, at the moment, no validated methods for the assessment of the permeation/penetration, such kind of studies could broaden the knowledge of the theme and produce important elements of evaluation.
Many scientific reports confirm the interest in formulating innovative UV filters carriers to achieve high skin photo-protection, contemporaneously reducing undesirable effect linked to skin permeation.
 Colloidal carriers have been demonstrated to promote the accumulation of the sunscreens in the uppermost layers of the skin, where their action should occur, by enhancing their photo-protection ability. Lipid nanocarriers are almost made of well-tolerated and biodegradable raw materials, which, together with the colloidal size of the particles that facilitates the formulation in dermatological products, enable confortable skin application.
 In recent years, several studies focused on the formulation of UV filters in micro and nanocarriers to protect them from photo-degradation and to prevent skin permeation.
Since it is noteworthy that BP-3 permeates across the skin leading to undesirable effects, a deeper knowledge of the influence of different formulation on its penetration properties could provide interesting implications.
 Martins et al. showed that BP-3 incorporation in solid lipid microparticles (SLM) with natural waxes, such as carnauba wax, was able to inhibit permeation and reduce 3-fold penetration with respect to free BP-3.
 The importance of the stability of microparticles has been underlined, since a degradation of the carrier components could lead to a faster release or not prevent skin penetration.
Moreover, it has been demonstrated that the cutaneous penetration of 4-MBC decreased when it was incorporated in polymeric cationic microspheres with respect to that obtained from free sunscreen, without change in SPF.
 The microspheres formulated in a W/O emulsion appeared to bind to keratin for a long period of time, thereby increasing the uptake of 4-MBC on the skin surface, especially stratum corneum, where it can explicit its action.
Nanostructured lipid carriers (NLC) are characterized by a solid lipid matrix, in which a liquid lipid is added; on the other hand, a wall of hydrophobic polymer surrounding their lipid core typically characterizes both nanostructured polymeric lipid carriers (NPLC) and nano-capsules (NC).
 It has been reported that NLC dramatically reduced the skin permeation and favored sunscreens localization in the superficial layers of the skin when compared to a nanoemulsion formulation.
 Among the sun filters tested, AVO and DHHB exhibited the higher flux at the steady state when formulated in nanoemulsion (log P 4.5 and 5.7, respectively) and showed a reduced flux when encapsulated in NLC. 
However, ETZ and BMZ, in any case permeated through the epidermis after 24 h, maybe due to their high substantivity for the stratum corneum as highlighted also by the value of log P that was >7 and 12.6 for ETZ and BMZ, respectively.
 It is interesting to underline that the degree of flux reduction after encapsulation, more considerable for DHHB, seems to be independent of both molecular weight and lipophilicity of the original molecule.
 It could be interesting for further works to deepen the physical-chemical characteristic of the complexes themself, as well as their mechanisms of interaction with the skin.
Moreover, since, in commercially available formulations, two or more sun filters are often combined to broaden the solar spectrum coverage in both the UVA and UVB regions, the effect of NC and nanoemulsion was evaluated on OMC and AVO simultaneously present in the same formulation.
 It was found that, when the sun filters were incorporated in NLC, they exhibit a lower flux than the nanoemulsion containing the same amounts of molecules. Furthermore, the application of NLC, both containing some filters, did not produce an appreciable increase in the amount of substance permeated through the full epidermal layer; on the contrary, the use of nanoemulsion led to a significantly higher amount of AVO and OMC with respect to the same emulsion containing only one of the two. Besides, Gilbert et al.
 Demonstrated that, when BP-3 was formulated into NPLC and NC suspensions, the polymeric envelope retained the molecule in the lipid matrix and the presence of poloxamer 188 in the aqueous phase could solubilize free BP-3, thus reducing BP-3 flux through the skin with respect to the albumin aqueous solution of the filter. 
Moreover, it was observed a better efficiency of polymeric nanoparticles to reduce BP-3 penetration in the skin layers and to show the highest in vitro SPF.
Another interesting formulation tool is represented by bioadhesive nanoparticles (BNPs), described by Deng et al. 
Starting from polylactic acid-hyperbranched polyglicerol (PLA-HPG) nanoparticles, the HPG was converted into an aldeide-rich corona with bioadhesive properties, and padimate-O was incorporated in these new highly skin adherent and not penetrant BNPs. 
The BNPs, thus prepared, remained on the stratum corneum after topical application, from which they could easily be removed with active towel drying because of water-resistance, and the deposition into hair follicle was prevented.
Among the properties that influence partition/dissolution of sunscreens agents into the surface of the stratum corneum and their diffusion through the lamellar lipid layers, it can be mentioned both the molecular weight and the lipophilic characteristics. 
In order to increase the dimension of the solar filter and its concentration in the upper stratum corneum, the formation of inclusion complexes with cyclodextrins has been investigated, also to increase the sunscreen photostability
They found that the complexation reduced the rate of permeation of sunscreens with respect to when the free filter was taken in account, also increasing the lag time, while the physical mixture affected permeation only for a little extent.
Another strategy to improve the effectiveness of sunscreens is the combination of organic and inorganic filters, as performed by Li et al.
 The authors encapsulated BP-3 into the inorganic UV-filter mesopouros silica (MS) by an in-situ sol-gel process using tetraethyl orthosilicate as a precursor and an ionic liquid as solvent and pore-forming agent. 
Moreover, they tuned up a cheaper and timesaving procedure, consisting in adsorbing BP-3 onto MS, used as drug delivery systems with a high surface area. A synergistic effect on the UV-absorption ability was observed and was ascribed to the lowered crystallinity of the BP-3 molecules and the additional light scattering induced by the mesoporous structure, which led to a greater optical density. 
Furthermore, it was found that an O/W emulsion containing the BP-3 adsorbed or included in MS exhibited in vitro SPF and UVA-PF higher than the free BP-3 containing emulsion and, at the same time, the in vitro release profile BP-3 through a cellulose membrane was significantly reduced. 
In particular, the encapsulation of BP-3 in MS produced the lowest flux through the membrane, suggesting a tightly entrapment of the filter in the MS matrix. The same authors in another paper used a modified dextrin as drug carrier for AVO.
 The dextrin was modified via reactions with alkyl oxiranes to create a biodegradable molecule and more stable against protein denaturation, with a decreased skin affinity.
 As previously reported for other products, encapsulation eliminates cristallinity of AVO, suggesting the entry of the molecule into the cavities of the modified dextrin; moreover, the release of AVO through a cellulose membrane from a cold-process prepared O/W emulsion containing the encapsulated filter was even slower than from the same emulsion containing the free-AVO, suggesting a low degree of skin penetration.
Recent studies confirm that exposure to solar radiation is associated with adverse effects on the skin, such as aging and cancer. 
As a result, effective sun protection and improved body defence system have become important research topics.
 Currently, most of the solar protection products on the market contain organic or inorganic UV filters that are primarily directed against radiation induced sunburn and DNA damage. 
However, some of these UV filters can penetrate the skin and at high concentrations can accumulate in the tissues, causing allergies and/or contact dermatitis.
In addition, filters can undergo photo-degradation following sunlight or artificial light exposure, leading to a decrease in their UV protection capability and to the generation of harmful photolytic products, such as free radicals and ROS. 
Therefore, recent studies aimed at searching for encapsulation or incorporation methods for organic UV filters in order to reduce skin penetration and to design an effective carrier based on new technologies in controlled delivery.
In the past, the stratum corneum was considered the only permeation barrier for chemicals to enter in the skin, but, in recent years, also viable epidermis and dermis has gained importance for their role in skin absorption of small molecules.
 Alterations of the biochemistry and the structure of the skin layers may have a role in molecular delivery through the skin. Recent studies highlight the role of UVA and UVA + UVB radiation in the expression of E-cadherin in the stratum granulosum, which contributes to epidermal barrier by governing tight junctions and whose levels are reduced by irradiation provoking epidermal thickening and wrinkled appearance.
 Moreover, radiation can induce some proliferative activity in the epidermal layers and an up-regulation of epidermal COX-2 expression in chrono-aged and photo-aged skin, suggesting inflammatory processes. 
Anyway, it has been demonstrated that not necessarily intrinsic and extrinsic aging increase skin permeation, especially in case of lipophilic permeants. An important role is represented by UVA radiation, the main responsible of percutaneous absorption during solar exposure.
The physicochemical properties of the solar filters are determinant in the process of penetration into and permeation through the skin layers.
 In particular, the log P value is a crucial element to assess if a molecule is able to permeate across the skin or not.
 Generally, a log P value above 2 indicates a high lipophilicity of the compound and it is likely that such molecules are capable of accumulating and forming reservoirs within the lipid phases of the stratum corneum. 
Additionally, these agents would have difficulty in penetrating the viable epidermis and dermis because of the hydrophilic nature of these layers. 
However, highly hydrophilic molecule would remain above the stratum corneum, while molecule that exhibited both aqueous and lipophilic properties are candidate to permeate the skin. 
Several studies pointed out on the tuning of micro- and nano-carriers to formulate chemical solar filters, in order to reduce their skin permeation and penetration, favoring the retention in the outer stratum corneum, where they are desired to act, and to protect them from photo-degradation.
The vehicle chosen to deliver filters to the skin is fundamental in influencing dermal absorption. 
The studies mentioned above suggest that the choice of high molecular weight filters and the use of O/W emulsions can contribute to obtain low skin permeation rates and high UV filter retention in the stratum corneum. 
Moreover, combination of UV filters and antioxidants could influence the skin retention of the filters, by reducing the amount of filters penetrated in epidermis and dermis. 
While filters must remain on the skin surface and have high substantivity for stratum corneum, antioxidants, present in the sunscreens formulation, should penetrate the skin to act as radical scavengers in the deeper skin layers, without reaching the systemic circulation. 
As well as penetration of UV filters in the skin layers, in addition to compromise the protective effect on the skin, can cause photosensitivity and an increased risk of allergic reactions, the combination of UV filters and antioxidants in a sunscreen can improve the efficacy of the product, with a synergistic effect in UV skin protection and antioxidant activity.
In the majority of the cases analyzed in this review, the in vitro evaluation of the filters behavior towards the skin is performed with vertical diffusion cells, in order to establish the entity of permeation and penetration of the molecule through and into the skin. 
In the last years, the follicular route has gained much importance and the differential stripping technique has been proposed, in order to differentiate transepidermal and transfollicular penetration, allowing the quantification of substances in all the skin compartments.
The entry into force in the European Union of the Cosmetic Regulation 1223/2009, with the ban for animal testing for cosmetics and the absence of validated alternative test for the skin permeation/penetration studies has led researches to increment the use of human tissues from abdominal or aesthetical surgery. 
Anyway, due to the lack of suppliers and the difficulties in availability, many researches in Europe are using pig ear skin, allowed because considered as waste material from slaughter, or in vitro reconstructed human epidermis from normal human keratinocytes.
There is still a long way to go, because, although formulation strategies are improving and the road to reduce the penetration of sunscreens seems to have been found, the methods to assess their skin permeation/penetration with a margin of accuracy and reproducibility and with reduced time and costs, in the respect of ethical principles, are still so far.
The backlash against traditional beauty companies — and the rise of “clean” ones — might have been inevitable. 
As scary-sounding reports about ingredients made the rounds over the years, consumers demanded answers. But cosmetics regulation laws in this country haven’t been meaningfully updated since 1938.
 The Food and Drug Administration, contrary to what some people assume, only has minimal oversight of the beauty industry. 
For the most part, beauty companies regulate themselves.
But now cosmetics industry regulatory legislation that languished for years is closer than ever to becoming law. 
And the traditional big beauty conglomerates are scared enough of the clean beauty backlash that even they are actively seeking more oversight. 
It’s going to fundamentally change how brands talk about beauty and how we as consumers shop for it.
Natural products used to be sold primarily in health food stores and farmers markets with labels decorated with pictures of leaves.
 It was a very specific niche and not taken seriously by the beauty industry. But now sleek new brands positioning themselves as “cleaner” alternatives to the mainstream are exploding.
Daniela Ciocan — the marketing director at Cosmoprof North America, an entity that hosts a large expo where brands can display their wares in hopes of landing retail placement — says that thanks to retailer and customer demand, this year the organization doubled the amount of space it dedicated to new “clean” brands at the 2017 convention.
In the past 12 months, so-called natural brands like Tata Harper and Jessica Alba’s Honest Company products have made up about a quarter of all higher-end skin care sales, according to the NPD Group.
 The category is growing at a faster rate than last year.
“We’re absolutely inundated,” says Annie Jackson, a co-founder of Credo, which was dubbed the “Sephora of clean beauty” when it launched in 2015. It currently has eight stores in the US and a robust online business, where it sells about 115 brands.
 Credo receives about 200 new products a month from brands hoping to sell there.
And it has a competitor. 
Follain, which opened before Credo in 2013 as a local shop in Boston, is growing rapidly. 
It currently has five stores, will open two more in October and expects to have 10 by the end of 2019. Its growth rate is up more than 200 percent in 2018.
In the meantime, customer demand means mainstream companies and retailers are giving more lip service to the concept of clean beauty. In 2017, Target bumped up its natural beauty offerings. 
CVS announced it was removing parabens and other ingredients from 600 of its house-branded products by the end of 2019. 
Brands regularly remove parabens and sulfates and the like, sometimes quietly and sometimes with great fanfare.
Sephora launched its “Clean at Sephora” initiative in May, citing in-house research that revealed that 54 percent of its skin care shoppers think it’s important that their products “have a point of view on clean” and looking to shop brands that are “grounded in a ‘free of’ ingredient perspective,” according to Cindy Deily, the senior director of skin care merchandising at Sephora, though she did not say free of what. 
Sephora received some criticism that its clean standards weren’t as rigorous as they could be, but Deily says the “no” list is still evolving.
And it’s not just retailers. Traditional companies are more transparent than ever, at least superficially. 
In February, Unilever announced it was voluntarily disclosing the fragrance ingredients in its beauty and personal care brands like Dove, Axe, and Suave. 
Johnson & Johnson is doing the same for its baby care products.
Because of the lack of regulation in the industry, all these new products have caused some confusion among consumers.
 The terms “clean” and “natural” are often used interchangeably and are the most common; you’ll also see “safe,” “green,” and “nontoxic.” 
Walk into Sephora and you’ll be confronted with signage that designates those products “Clean by Sephora.” Walk into Nordstrom and you have to ask where the natural products are. 
But because the terminology isn’t regulated by an agency or governing body like the Federal Trade Commission or the FDA, they’re all essentially meaningless words when they appear on cosmetics and personal care products.
 Natural usually tends to mean it contains plant-based ingredients, though there’s a push by some new brands to move away from the word natural because there are many safe synthetic ingredients. 
But it’s still a free-for-all. Usually clean products are notable for the ingredients they are free of: parabens, phthalates, sulfates, and more.
The designation “organic” as it relates to cosmetics is even more confusing. The US Department of Agriculture, the organization that regulates food, has rules about what kinds of products can be labeled as organic; in beauty, it’s dependent on what percentage of USDA standard organic ingredients are in the product. But ultimately, being organic doesn’t make an ingredient better or safer, as the FDA notes.
So any company can call a product “natural” or “clean” and define that term any way it wants.
 And companies don’t hesitate to slap on that label, because shoppers respond to it. A 2018 survey by students in the Fashion Institute of Technology’s graduate school of cosmetics and fragrance marketing and management found that “90% of consumers believed that natural or naturally-derived beauty ingredients were better for them.” 
Of course, a lot of natural things can be bad for you. Poison ivy. Cyanide in apple seeds. Some essential oils.
But it’s led to a misconception among some consumers that chemicals equal danger.
 “I can’t tell you how many times I see a product that says ‘free of chemicals,’” says Kelly Dobos, a cosmetic chemist of 15 years. “It’s ridiculous because water is a chemical.”
Certain ingredients have garnered headlines throughout the past 10 years, bringing cosmetic safety to the forefront. 
In 2010, large amounts of chemicals that turned into formaldehyde gas when heated were found in a popular hair straightening treatment from the brand Brazilian Blowout. 
The Occupational Safety and Health Administration called it a hazard for salon workers and potentially for customers. 
In 2012, the FDA discovered that 400 types of lipsticks contained tiny amounts of lead; the effects on humans are unknown.
In 2014, following consumer outcry, Johnson & Johnson removed a type of preservative from its baby shampoo that releases very small amounts of formaldehyde into the air.
 In 2017, the American Journal of Obstetrics and Gynecology issued an opinion stating that women of color were disproportionately exposed to problematic ingredients in beauty products, partially because of the societal pressure on them to use hair relaxers and skin lightening products.
Clean beauty proponents often cite the statistic that the European Union has banned more than 1,300 chemicals from being used in beauty products while the US has only banned about 30. 
And this is true. The clean beauty market is made up of brands that have voluntarily cut these chemicals from their products. 
Like parabens, for example. Parabens make up a category of preservatives that have been widely used in cosmetics for decades.
 Any water-based product, which includes everything from shampoo to lotions, needs to contain a preservative to prevent the product from growing bacteria and fungus while it’s sitting in your medicine cabinet. 
But “paraben-free” is the most frequent claim you’ll see on beauty products these days.
Parabens are known to weakly mimic estrogen in certain situations, which gained them the description “endocrine disruptor.” 
In 2004, the Journal of Applied Toxicology published a study in which researchers found parabens in breast cancer tissue. 
It’s important to clarify that they did not test the women’s healthy tissue, and they did not suggest that the parabens caused the breast cancer. But this study was the first to the chemical some notoriety among consumer watchdog groups.
In 2014, the EU banned some parabens; this is really when the outrage against them peaked in the US.
 But the fact that Europe did not ban some of the most commonly used parabens was widely overlooked. 
The European Scientific Committee on Consumer Safety wrote:
The group of chemicals known as parabens make up an important part of the preservatives which could be used in cosmetics.
 In addition to Propylparaben and Butylparaben, other parabens, like Methylparaben and Ethylparaben, are safe, as repeatedly confirmed by the Scientific Committee on Consumer Safety (SCCS).
 They are also some of the most efficient preservatives.
Large organizations like the American Cancer Society put out statements that the data about parabens’ harm to humans was limited, writing: “There are also many other compounds in the environment that mimic naturally produced estrogen.”
Parabens may well be terrible for us, but for now the long-term effects of parabens on humans are simply unknown — there is no conclusive data that they hurt us.
 But the seeds of doubt were planted, consumers balked, and companies started removing them, thus reinforcing the belief that parabens must be bad. You’ll find them in very few products these days.
But how afraid should you actually be? In toxicology, the study of chemicals and their effect on living things, the mantra is “the dose makes the poison.”
 “If you give enough of any chemical, it will produce harm,” says Dr. Curtis Klaassen, a toxicologist who edited the textbook Casarett & Doull’s Toxicology: The Basic Science of Poisons. 
He also evaluates chemical data as an independent scientist for the Cosmetic Ingredient Review, a regulatory council created by an industry trade group.
Take formaldehyde, which has been labeled a human carcinogen. “It was discovered about 25 years ago that it is a carcinogen when they exposed rats and mice to very high concentrations in the air,” says Klaassen. “But it turns out that you and I make formaldehyde [in our bodies].
 Its likelihood of causing cancer in humans at the dose that you’re exposed to from washing your hair is essentially zero.”
We will likely never conclusively know the effects of years of daily use of these chemicals. 
It’s impossible to study in a controlled way, and the sheer number of ingredients we use on a daily basis makes it difficult to ever pinpoint a toxic smoking gun. 
But some argue that’s the whole point.
“What we’re most concerned about is the overall [chemical] body burden,” says Nneka Leiba, the director of the Environmental Working Group’s Healthy Living Science program. 
“Companies hear our position on that and sometimes they agree and sometimes they don’t.”
Some watchdog groups have become powerful in challenging the mainstream beauty establishment on this issue; the EWG, established 25 years ago as a nonprofit to look at pesticides and food, is arguably the most powerful one.
 But since then, it’s expanded to larger environmental and human health initiatives, including cosmetics. 
In 2004, the same year the breast cancer paraben study was released, the group published its first Skin Deep cosmetics database.
The EWG’s database contains more than 73,000 products and ingredients, giving them a rating for their potential hazards based on a complicated set of data and methodology. 
Leiba says a staff of 12, including toxicologists, chemists, and public health specialists, review the data on ingredients and update it regularly. 
“We speak to external scientists and industry scientists and see where we differ from them,” Leiba says. “Most of the times we realize we are erring on the side of precaution.”
The Skin Deep database has become a go-to resource for consumers, a go-to reference for the media — especially for its popular annual sunscreen guide — and a pain point for many brands.
 But it’s been criticized for perceived fearmongering along the way by some cosmetic chemists and others, as well as for rating inconsistently and giving ratings when there is limited data available.
“I agree with a great deal of what they do. 
We have a lot of carcinogenic materials. 
The vast majority of the problem is the chemicals that are being used both for cosmetics and for household cleaners are made using some really environmentally destructive methods,” says Gay Timmons, owner of Oh, Oh Organic, a company that provides organic cosmetic ingredients to companies like Aveda. 
Still, Timmons says, “EWG has had a big role in frightening consumers. That’s really very much the tack they have taken, for good or for bad.”
Leiba does not agree with that characterization of the EWG, saying they just want customers to understand they have options: “We are staunch in the fact that we’re not fearmongering. 
We’re educating. We’re not saying, ‘Don’t get this, don’t get that.’ We take a precautionary approach. 
That’s the same approach the European Union takes when it’s regulating chemicals.”
Part of the reason we’re in this confusing mess is that the FDA is not empowered by law to actually regulate the beauty industry. 
Based on the 1938 Federal Food, Drug, and Cosmetic Act, the only ingredients it can approve before they hit the market are color additives. 
It can’t order product recalls, but it can request them. 
If it thinks a product is contaminated or misbranded, it can work with other agencies to take legal action and does conduct occasional testing, as in the lead lipstick situation, if it has safety concerns. 
Ingredient safety is the biggest point of contention, though, because companies are expected to determine that on their own — which is kind of a joke because, per the FDA website, it doesn’t require companies to demonstrate safety or even share information.
The Personal Care Products Council, the beauty industry’s biggest trade group, formed the Cosmetics Ingredient Review 40 years ago. 
The CIR reviews data and studies on about 300 to 500 ingredients per year and offers judgment about their safety.
Each CIR panel member must pass a conflict of interest analysis, and a representative from the FDA and a consumer advocate group called the Consumer Federation of America sit in on meetings. 
The reports are finalized, peer-reviewed, and then published in the International Journal of Toxicology. 
But because the PCPC, whose members include some of the biggest beauty conglomerates in the country, funds the CIR, its conclusions just aren’t trusted the way they would be if it were a truly objective organization. 
Ironically, it’s been accused of the same thing the EWG has — passing judgment on ingredients where there is limited data. 
And it should be noted that the EWG partially relies on data from and refers to the CIR in its own rating system.
In the beauty and lifestyle media, ingredients are regularly referred to as “toxic” while clean brands are called “nontoxic.”
According to a report on the industry site Cosmetics Design, the PCPC all but begged beauty editors to talk more about science at the organization’s last annual meeting. 
“The misinformation that’s out there drives the scientific side of me crazy,” the PCPC’s chief scientist told the room. 
And now they’re asking the FDA for oversight too. “Consumers are very confused and the beauty industry and brands are very frustrated. 
This is something that cannot be solved by industry. 
Industry has tried and has lobbied the federal government constantly over the years for more funding to the FDA,” says professor Stephan Kanlian, who is the chair of FIT’s master’s program in cosmetics and fragrance marketing and management.
Scott Faber, EWG’s senior vice president for government affairs, agrees. “Big companies have been working with us to give FDA more authority because consumers don’t trust the regulatory programs like CIR.” 
He compares it to the situation last year, when, as Politico reported, some large food companies like Nestle and Campbell Soup Co. left their grocery trade lobbying organization because its policies weren’t perceived to be in step with what consumers wanted.
So we may finally be closer to stronger regulation. 
There are several pieces of legislation pending now. Rep. Frank Pallone (D-NJ) submitted a discussion draft for a House bill to regulate cosmetics in 2016. Sen. Orrin Hatch (R-UT) introduced the FDA Cosmetic Safety and Modernization Act at the end of 2017, which the PCPC publicly supported at the time, though it’s unclear if it still does.
But the most prominent proposal is the Personal Care Products Safety Act, introduced by Sen. 
Dianne Feinstein (D-CA) and co-sponsored by Sen. Susan Collins (R-ME). It’s been around in various forms since 2015. Basically, it gives the FDA the same power over cosmetics that it has over drugs and medical devices. 
The FDA could inspect safety records and mandate recalls. The bill also requires the FDA to review safety data on at least five ingredients per year. Companies will be charged a fee on a sliding scale depending on size to help fund the FDA so it can fulfill its new responsibilities.
The EWG has been devoting resources to draw attention and publicity to the bill, including even bringing Kourtney Kardashian to Washington, DC, for a briefing at the Capitol.
Beautycounter, a multilevel marketing beauty company that has banned 1,100 ingredients in its products and has been a visible and vocal voice in the clean beauty movement, has also supported the bill publicly. 
The company has a team dedicated to advocacy and it’s made multiple trips to Washington for hearings and meetings with lawmakers. 
Lindsay Dahl, Beautycounter’s vice president of social and environmental responsibility, says “a Senate version of the bill is about 95 percent negotiated, which is no small feat.” 
But because of the Brett Kavanaugh Supreme Court hearings and a focus on the November midterm elections, industry sources suspect the bill might be tabled until early 2019.
You can be excused for being skeptical about whether the current administration, which has shown itself to be decidedly anti-regulation, would support a bill regulating an industry that primarily affects women and their health. 
But it has bipartisan support, and the EWG’s Faber is hopeful.
“FDA has been a pleasant surprise. Commissioner Scott Gottlieb and his team understand that it’s government’s job to keep us safe from dangerous products. 
Which is a departure from some of President Trump’s appointees,” says Faber. 
The FDA even just launched its first-ever survey of safety practices and manufacturing standards of cosmetic companies, indicating that it is gearing up for more oversight of the industry.
None of this legislation is perfect and all-encompassing, and there is still a lot of data missing on ingredient safety. 
Even “clean” beauty produts contain ingredients that have no data one way or the other on safety. 
Plus, it’s not clear how the FDA would or could provide guidance on labels like “natural” or “clean.” 
But it would be a win-win for both companies and consumers, at least superficially.
Big beauty companies would be relieved of some of the burden and bad press that has come with regulating itself.
 For shoppers, it could seem like there is an objective entity looking out for them.
There are some downsides to pulling ingredients out of products, though, especially if there aren’t good alternatives. 
The Honest Company has been plagued with recalls, lawsuits, and complaints through the years because of faulty products. It’s going through a bit of soul-searching and reorganization.
Then there’s the risk of ditching well-known preservatives like parabens. “I have actually seen more recalls for microbial contamination in the past few years than I’ve seen in all my years in the industry,” says Dobos, the cosmetic chemist. 
Just this month, Avalon Organics and Bath & Body Works issued recalls for microbial contamination in some of their products.
What’s important to remember is that in the meantime, clean brands and retailers are still trying to sell you things just like the traditional beauty companies are, even if some of them truly have public health top of mind. 
Marketing themselves as “clean” is an advantage in this market. Even the EWG utilizes Amazon affiliate links on its product pages, meaning if you click through to Amazon to purchase, the EWG gets a percentage of the sale. 
It also sells a special certification label to companies allowing them to state their products are “EWG verified.”
“We are trying to make money,” says Beautycounter founder Gregg Renfrew.
 “We are doing well by our financial stakeholders while simultaneously creating significant social impact. 
The companies that are going to be successful in future will do both.”
In FIT’s report on industry transparency, the authors quoted an infectious diseases specialist reacting to the anti-vaccination movement in recent years. 
People are scared of ingredients, and they have made that clear with their dollars. 
Eventually, the clean beauty industry is going to just become ... the beauty industry.
Forms of body decoration exist in all human cultures. However, in Western societies, women are more likely to engage in appearance modification, especially through the use of facial cosmetics.
 How effective are cosmetics at altering attractiveness?
 Previous research has hinted that the effect is not large, especially when compared to the variation in attractiveness observed between individuals due to differences in identity. 
In order to build a fuller understanding of how cosmetics and identity affect attractiveness, here we examine how professionally-applied cosmetics alter attractiveness and compare this effect with the variation in attractiveness observed between individuals.
 In Study 1, 33 YouTube models were rated for attractiveness before and after the application of professionally-applied cosmetics.
 Cosmetics explained a larger proportion of the variation in attractiveness compared with previous studies, but this effect remained smaller than variation caused by differences in attractiveness between individuals.
 Study 2 replicated the results of the first study with a sample of 45 supermodels, with the aim of examining the effect of cosmetics in a sample of faces with low variation in attractiveness between individuals. 
While the effect size of cosmetics was generally large, between-person variability due to identity remained larger. Both studies also found interactions between cosmetics and identity–more attractive models received smaller increases when cosmetics were worn. 
Overall, we show that professionally-applied cosmetics produce a larger effect than self-applied cosmetics, an important theoretical consideration for the field. 
However, the effect of individual differences in facial appearance is ultimately more important in perceptions of attractiveness.
Modification of the body with dyes, paints, and other pigments is among the most universal of human behaviours, present in all culture.
 However, in Western society, women perform the majority of self-adornment, and perhaps the most prevalent behaviour of this kind is the use of facial cosmetics.
 This behaviour is served by the global cosmetics industry which is worth billions of pounds.
Women report using cosmetics for a variety of reasons, ranging from anxiety about facial appearance, conformity to social norms, and public self-consciousness, through to appearing more sociable and assertive to others.
 Cosmetics are effective at improving social perceptions that the wearer may wish to modulate, with individuals appearing to be healthier and earning more, displaying greater competence, likeability and trustworthiness, as well as appearing more prestigious and dominant. 
Cosmetics also influence the behaviour of others, especially men, who tip higher amounts and with greater frequency to waitresses wearing cosmetics, and are more likely to approach wearers in the environment.
 It is likely that the effect of cosmetics on social perceptions is brought about by the increase in attractiveness it confers to faces, which is now a well documented effect.
 Research has documented cosmetics function by altering sex-typical colouration in faces such as facial contrast, by increasing the homogeneity of facial skin, or by affecting colour cues to traits such as health  and age.
While the effect of cosmetics on perceived attractiveness seems clear, other research has revealed it is more nuanced than previously thought. Etcoff and colleagues demonstrated that attractiveness increased linearly with the amount of cosmetics worn—simply, more cosmetics equates to appearing more attractive. 
Of the range of cosmetics that can be worn, the quantity of cosmetics applied to the eyes and mouth have been shown to be significant predictors of attractiveness, with more cosmetics on these features leading to higher ratings of attractiveness. 
However, other evidence suggests that the typical amount of cosmetics applied by a sample of young women is excessive, with observers preferring close to half the actual amount for optimal attractiveness, calling into question the linear relationship between cosmetics quantity and attractiveness.
One concern of facial attractiveness research is that it does not compare the effects of predictors of attractiveness.
Recent work has begun to address this by examining the importance of within-person variation in attractiveness (caused by the presence or absence of makeup, for example), compared with the between-person variation in attractiveness simply due to differences between identities.
 Specifically, it has been previously shown that the effect of cosmetics on attractiveness, a source of within-person variation, is very small, explaining just 2% of the variance in ratings.
 This is an especially small effect when compared with differences in attractiveness between individuals, a between-person variation in attractiveness, which explained 69% of the variance in judgements. 
More simply, while facial cosmetics do increase attractiveness, that contribution is small and does little to change an individual’s attractiveness standing in the population.
However, the use of cosmetics is an idiosyncratic and extremely varied practice, and its effect on attractiveness is more complex than previously thought. 
The use of a professional makeup artist is a common practice in almost all studies examining the effect of cosmetics on perceptions, and only a few utilise self-applied cosmetics.
 An initial examination of the effect size of cosmetics on attractiveness also had models self-apply their cosmetics. There are good reasons for using professionally-applied cosmetics, as it provides a clearer test of how cosmetics alter facial attractiveness. The increased variability in self-applied cosmetics, due, for example, to differences in application skill or the products used, could make it more difficult to detect an effect of cosmetics on attractiveness, and previous work has indeed found the effect to be small.
 This distinction represents a trade-off between experimental control and ecological validity—the vast majority of women, if any, do not have a professional makeup artist apply their cosmetics daily, yet the majority of studies examining cosmetics and attractiveness draw conclusions based on professionally-applied cosmetics, which may only indirectly inform as to how cosmetics affect attractiveness in the real world.
We seek to address important theoretical points regarding how cosmetics influence attractiveness. How large is the effect size of cosmetics on attractiveness when cosmetics have been professionally-applied? 
If cosmetics in psychological experiments are applied with more skill than is typically achieved, then current knowledge of cosmetics and attractiveness likely overstates the relationship, given the reliance on professionally-applied cosmetics in the literature. 
Moreover, how does the ability of professionally-applied cosmetics compare to previous measures of the effect of cosmetics on attractiveness? In the following study, we examine the effect size of cosmetics on attractiveness in two sets of faces that have had cosmetics applied professionally, with the prediction that the effect will be substantially larger than the previous assessment that considered self-applied cosmetics. 
In addition, by using a similar design to previous research, we can draw direct comparisons with current knowledge of how cosmetics and identity affect attractiveness.
A separate but related question regarding cosmetics concerns how it affects faces of different levels of attractiveness. Many studies in the literature on cosmetics and social perceptions have used models recruited from university or college.
 How do cosmetics affect faces of a different population, specifically faces considered to be very attractive? Previous research found no interaction between cosmetics and identity, suggesting cosmetics affect each face’s attractiveness similarly. 
However, the models used were of a university-aged sample of population-typical attractiveness levels. 
The present studies, particularly Study 2, examine the effect cosmetics have on perceived attractiveness in a sample of women typically considered to be very attractive—models. 
Using a sample of faces that are already constrained in attractiveness enables us to manipulate another source of variation in attractiveness, specifically between-person variability. 
As such, we can observe the effects of cosmetics on attractiveness in a sample with a (hypothesised) lower effect of identity (differences between individuals) than elsewhere.
The present study has several aims. 
First, we examine how cosmetics affect attractiveness when cosmetics have been professionally-applied. We predict that cosmetics will have a notably larger effect size in this sample compared to the previous study examining this question. 
Second, we consider the effect size of cosmetics in sets of faces that are considered highly attractive, where between-person variation (identity effect size) should be reduced. 
The relative effect size of cosmetics may therefore be increased, and may be more likely to overshadow the smaller between-person variation in attractiveness. 
Conversely, cosmetics may have less of an effect in these samples as the women are already at the higher end of attractiveness without cosmetics, leaving little room for judgements of attractiveness to increase when cosmetics are applied. 
Finally, by using an identical design to previous research, we will compare the findings obtained in these studies to those presented in previous research in order to build a fuller picture of the relative importance of cosmetics and identity in attractiveness perceptions.
In the first study, we examine how cosmetics impact attractiveness when they are applied professionally. 
To do this, we take advantage of an Internet-based sample to acquire images of models whose cosmetics have been applied by high-profile makeup artists. 
Compared to previous work examining this question, we predict that the effect size due to cosmetics should be larger here. However, the effect size of identity may still overshadow it.
Ninety North American university students participated in the main study for course credit. 
Due to a software error, age data was not recorded for the first 50 participants, with the mean age being calculated from the remaining participants. 
However, all participants were within the same demographic and age range. A further 15 students  rated the quantity of cosmetics worn by the models. Informed consent was obtained from all participants included in the study.
Ethical approval for all studies was obtained from the Gettysburg College institutional review board. All participants gave written informed consent before beginning the study.
From the YouTube website, we collected images of White British women, who acted as models while their cosmetics were applied by high-profile professional makeup artists from the United Kingdom. 
Twenty-three models were obtained from one artist’s channel with a further ten collected from another. We utilised all available videos at the time of writing that featured a model receiving a makeover where they were shown before and after an application of cosmetics. 
In addition, we included only videos where faces began free of cosmetics, and the artist had the intention of applying a particular cosmetics look, rather than with the aim of hiding blemishes or skin conditions (such as acne).
 Images were captured from video tutorials, which served to instruct viewers on a number of popular cosmetics styles for a range of scenarios. 
Both authors classified the cosmetics looks into categories using information provided by descriptions within the videos. 
Three categories were apparent—an everyday, natural look, a ‘going out’ look, and vintage or editorial looks based on cosmetics the makeup artist had applied during professional photo shoots in the past.
 A third researcher, with extensive experience in this field, arrived at these three categories independently, providing further confirmation.
We captured a high-resolution screenshot of each model at the end of each video, where images of the models were presented before and after their application of cosmetics side-by-side.
 Models had a neutral expression and looked directly into the camera for the comparison.
 In addition, the two photographs were taken under the same lighting and camera conditions. From each comparison screenshot, we cropped the ‘before’ and ‘after’ versions of each model to produce two separate images. 
Final images were cropped just below the chin, at the hairline (or mid-forehead based on the limitations of the original), and tight to the widest part of the face (and so removing the ears). Given the variable nature of the images in terms of hairstyle, we chose models whose hair did not occlude their faces, and we masked loose hair in the lower portions of the images if it was not tied back. 
Images were resized to a height of 451 pixels. Given copyright restrictions, we present the average of models without cosmetics, and separately with cosmetics. 
Averages were produced using JPsychomorph after landmarks were applied to the facial features in each image.
Participants rated the attractiveness of the models using custom PsychoPy software.
 Images were presented in a random order, and each participant rated each model only once, in a randomly selected cosmetics condition.
 This design was specifically chosen to prevent carryover effects between conditions. 
Participants rated the attractiveness of the models on a 1  to 7  scale, indicating their response via mouse click. Stimuli remained onscreen until a judgement was made.
A separate sample of participants judged the quantity of cosmetics worn by the models. 
These participants saw the ‘without’ and ‘with cosmetics’ images onscreen next to each other, and were asked ‘how much makeup has been applied to this face?’ 
Participants indicated their responses via mouse click on a 1 (very light) to 7 (very heavy) scale. Trials were presented in a random order. 
Though this is only a perceived measure of quantity, rather than an actual quantity of cosmetics, we believe it to be suitable as it is the perceived quantity that would affect the perceptions of observers. Importantly, other studies have found general agreement in the quantity of cosmetics applied by a professional makeup artist and the perceived amount of cosmetics being worn.
Each image was rated an average of 45 times.
To examine effects of observer sex on ratings, the data were split by the sex of each observer before averaging.
 This resulted in four scores for each model—one in each cosmetics condition, as rated by men and women.
We also calculated the average amount of perceived cosmetics applied (M = 4.96, SD = 1.09), as judged by the separate sample of raters. These judgements of quantity were collected in order to be able to control for the varying amounts of cosmetics worn by each model in our analyses. However, this measure showed no relationship with the dependent variable (attractiveness) at all levels of observer sex and cosmetics.
 As such, there was no reason to include quantity as a covariate, and we therefore analysed our results using a repeated measures ANOVA with model as the unit of analysis.
We focus here on the effect sizes of variables in order to estimate the real world effect of cosmetics on attractiveness. 
In particular, we utilise eta squared (η2) as a measure of effect size, which expresses how much each factor contributes to the total variance in attractiveness ratings as an interpretable percentage value, rather than partial eta squared, which does not sum across factors to one. 
We calculated η2 effect sizes for both main effects (Cosmetics, Observer Sex) and the interaction by dividing the sums of squares (SS) attributable to each effect by the total SS, calculated by summing the SS attributable to each effect and their respective errors. 
We also gave special consideration to the variance attributable to differences between items. This variation is typically ignored in repeated measures analyses since it usually represents variation between participants on the measured dependent variable, which is generally unimportant for repeated measures designs (which instead focus on variation within participants). 
However, in this case, it takes on a useful property. 
By using the images of the models as the unit of analysis, the variation between models represents variation in attractiveness arising due to the fact that models have different facial identities or appearances. 
We were therefore able to calculate an effect size for this ‘identity’ measure. The full results of the ANOVA are reported, illustrating the effect sizes, their associated SS, and other statistics.
 It should be noted that there is no error term for conducting an F test on differences between models, and as such, no F ratio is calculated interactions with the Identity measure can be interpreted as an error term for that variable.
The models used in Study 1 were women who had agreed to participate for the purposes of demonstration in a makeup tutorial. We have shown that the effect of cosmetics, when professionally-applied, results in a larger effect size compared with previous research.
 Next, we investigate how cosmetics alter the attractiveness of a sample of women who are generally regarded as very attractive and earn a living based on their appearance—supermodels.
 We examine how much variation in attractiveness can be explained by cosmetics, and compare it with the effect size of identity, the differences in attractiveness between supermodels. 
Here, the effect size of identity should be smaller, given the potentially homogenous nature of the women in terms of attractiveness. 
How much of a benefit do cosmetics confer to highly attractive women, and in turn, do cosmetics overcome the differences in attractiveness between individuals?
Ethical approval for all studies was obtained from the Gettysburg College institutional review board (IRB). 
All participants gave written informed consent before beginning the study. The Ethical Governance and Approval System at the University of Aberdeen granted approval for the study conducted there. 
Again, all participants gave written informed consent before beginning the study.
We collected images (n = 45) of supermodels without their makeup from the Internet. These images were casting photographs for Louis Vuitton’s Fall-Winter 2010 runway show. 
All pictures were taken with the models looking directly into the camera, with a neutral expression. We then collected images of the same women wearing cosmetics from professional photo shoots, and selected images where they had a neutral expression and were looking directly into the camera in order to match the casting photographs as closely as possible.
 However, these cosmetics photos were considerably less constrained in that the lighting varied between images, as did the amount of time between the two photos for each model. Therefore, while every care was taken to ensure similarity between these images and those of Study 1, we note that such limitations mean that any conclusions drawn from this study are necessarily more tentative.
Final images were cropped as in Study 1 to just below the chin, at the hairline, and tight to the widest part of the face (and so removing the ears). 
Hair was masked at the bottom of the images as before, and images were resized to a height of 250 pixels. Given copyright restrictions, we present the average of supermodels without cosmetics, and separately with cosmetics
We have shown that professionally-applied cosmetics increase the attractiveness of both models and supermodels, with generally larger effect sizes than have been observed elsewhere.
 Here, we combine the data from Study 1 with the data reported in previous work that provided an estimate of the effect size of cosmetics when self-applied to a student population.
 This will allow a comparison of both model sets without and with cosmetics, and an overall comparison of the effect size of cosmetics and identity in a pooled setting of cosmetics use. 
We included only the models from Study 1 as these images were captured under more controlled conditions, similar to the images used in the previous work. In the initial study, there were 44 self-reported White women acting as models.
 Models applied their own cosmetics from a range of provided products, and were rated using the same procedure used here. 
To conduct this analysis, we employed a three-way mixed ANOVA: Set (Students, YouTube) × Cosmetics (With, Without) × Observer Sex (Female, Male). 
Set represented a between-subjects factor, while the remaining factors were both within-subjects. As before, the model was the unit of analysis. Since a factorial ANOVA produces several statistical tests, we focus on the theoretically important outcomes.
 In this case, an interaction between Set and Cosmetics indicates that an application of cosmetics affects the model sets differently. We would predict models that received an application of professional cosmetics would appear more attractive.
The predicted interaction between Set and Cosmetics was present.
 Bonferroni adjusted post-hoc tests revealed that without cosmetics, the YouTube models were rated as slightly more attractive than models from the student set.
 However, with cosmetics, YouTube models  received significantly higher ratings of attractiveness than the student models, indicating a larger change in attractiveness with professionally-applied cosmetics than with self-applied cosmetics.
We can also draw comparisons between the sizes of our effects across all three studies (the two presented here and the student set). 
While η2 is ideal for comparing effect sizes within a study (the total always sums to 100%), comparison between studies is generally not recommended because the total variability depends on the study design and the number of independent variables.
 However, the two studies reported here, as well as earlier data, use identical study designs, and the total variability is very similar in all cases.
 The main differences were the models used and the type of cosmetics applied. As such, we can justifiably make some comparisons between the effect sizes of cosmetics and identity across these studies.
While the effect size due to identity was similar, the earlier study using students showed a much larger effect.
Therefore, while variation in attractiveness between individuals was somewhat greater among a sample of university students as compared to models and supermodels (as we would expect), the effect size of professionally-applied cosmetics was much larger than self-applied cosmetics.
 It is also important to note that the effect sizes obtained for the data in Study 2 are to be interpreted cautiously, given the more unconstrained nature of the images.
Across several studies, we find that using cosmetics increases perceptions of attractiveness compared to no cosmetics, with several novel findings and caveats. 
First, we show that the effect size of cosmetics on attractiveness is large when those cosmetics have been professionally-applied, though the effect of identity is still greater. 
However, the difference between identity and cosmetics effects is much smaller than in a student sample of faces with self-applied cosmetics.
 Second, we show that in a sample of supermodels with a smaller, more constrained effect size of identity (i.e., reduced between-person variance in attractiveness), identity is still more important than cosmetics, though the effect size of cosmetics is still larger than in previous cases. 
In both cases, but particularly the set of supermodels, we found evidence of an interaction between facial identity and cosmetics, indicating a differential effect of cosmetics on attractiveness. Further analysis revealed that the more attractive a face was without cosmetics, the less of an increase in attractiveness cosmetics conferred.
Across all studies, we observed that the effect of facial identity was larger than the effect of cosmetics. This finding extends previous research demonstrating that between-person variation is consistently larger than within-person manipulations of attractiveness.
 Interestingly, the ratio between the effect sizes of identity and cosmetics in these studies (i.e., how much more variation identity explained than cosmetics in attractiveness judgements) is smaller than the comparison observed with emotional expression, suggesting that professionally-a—pplied cosmetics might be more effective at modulating attractiveness perceptions than facial expression, at least in female faces. 
Additionally, the finding that identity might be more important than within-person variation should perhaps be interpreted with caution. We refer to ‘identity’ in the current paper but use single, passport-style images of each model.
 However, individuals appear differently across different photographs, and this within-person variation in appearance has also been shown to affect perceived attractiveness.
A surprising source of variance in both studies was the interaction between identity and cosmetics. 
This finding, indicating that cosmetics affected different faces differently, was analysed further to reveal that the more attractive a face was initially, the less of an increase in attractiveness cosmetics conferred. 
While this is an intuitive finding, it has not been demonstrated before, and was particularly pronounced in the set of supermodels where the effect size of the interaction was almost as large as that of cosmetics itself. 
Cosmetics confer attractive patterns of colouration to faces, enhancing sex typical features in skin reflectance, as well as smoothing skin homogeneity and colour distribution.
 Female faces that are considered attractive tend to have lighter skin, darker eyes, and redder lips than the average female face, which are all correlates of attractiveness, and in a recent study, are colourations that are conferred to faces by cosmetics.
 It may be that the more attractive faces  already possess the most attractive features that cosmetics can alter, and so there is little change in attractiveness after an application. 
That less attractive faces receive more of an increase from cosmetics also has practical implications. 
By definition, the majority of women will lie around average attractiveness, and so a significant number of women could receive a boost in attractiveness from cosmetics.
We also found that the perceived quantity of cosmetics applied to faces played almost no role in the perceived attractiveness of faces with cosmetics. 
Recent evidence has shown that faces with lighter makeup are perceived as more attractive than faces with heavier makeup which is at odds with our findings here. 
However, that study used different models for each cosmetics condition, conflating sources of cosmetics and identity variance, as well as using digitally applied cosmetics.
 While observers seem to find lighter cosmetics optimally attractive when given the choice to vary the quantity, no study as of yet has systematically shown that lighter cosmetics are optimally attractive for a given face. 
Our measurements here, as well as previous data, seem to suggest quantity does not play a large role in perceptions of attractiveness with cosmetics.
Combining image sets from previous researchwith the findings from Study 1 revealed that, while the models from Study 1 were slightly more attractive than the models from the previous study, they were rated as significantly more attractive with cosmetics.
 After considering the similarity of designs and total variability across all studies, we compared the effect sizes of identity and cosmetics directly. 
Variability due to attractiveness between individuals (identity) was smaller among models and supermodels compared to university students, as predicted, but the effect size of cosmetics was noticeably larger for professionally-applied cosmetics. 
However, it is important to note that the sample sizes of models differed, and larger sample sizes might also result in greater between-person variability.
These findings have relevance for investigating the effects of cosmetics on social perceptions. There now exist estimates of the effect size of cosmetics when they are self-applied, and when they are applied professionally. 
In previous work, cosmetics explained just 2% of the variation in attractiveness, while the finding from a sample of models showed cosmetics explained 33% of the variation in attractiveness. 
This study demonstrated larger effect sizes of cosmetics when directly compared to previous research, though the studies used different sets of faces, and it is important to note that any effect size estimate calculated is ultimately based on the context of the research, and should be interpreted within this context.
 However, the variances in the current and previous research are very similar, and the design of the studies is identical, meaning direct comparisons are valid and appropriate.
The literature examining the effect of cosmetics on social perceptions has, for the most part, used models with professionally-applied cosmetics in laboratory studies as well as field experiments. 
With our comparison of the effect size of cosmetics under both self-applied and professionally—aaaapplied conditions, it seems possible that some of the effects of cosmetics observed in the literature may be inflated. 
Further, women report higher self-confidence and engage in more social activities after a professional makeover and this increase in self-confidence may translate into slight expression or postural differences in images, which could represent an additional within-person boost in attractiveness due to cosmetics.
There are some caveats to the study. Images were obtained from various Internet sources, and so were not as constrained in lighting or emotional expression as previous research. 
Study 1 suffered less from this potential issue as images were collected from the same photographic session. 
As the images of supermodels with cosmetics were obtained from different sources, while the images of those women without cosmetics were obtained from the same source, the magnitude of the interaction between identity and cosmetics should be interpreted with caution.
 However, given its presence in Study 1 with more controlled stimuli, we think it safe to conclude that cosmetics affect more attractive individuals to a lesser extent than others. Furthermore, that such an effect was obtained in Study 2 with more variable photographs could be considered strong evidence. 
Since the images were more variable and cosmetics were confounded with variations in lighting (both considered noise in the current study), it seems likely an effect would be obtained under stricter conditions.
There now exists convincing evidence that alterations to within-person facial appearance via cosmetics, whether self-applied or professionally-applied, do not overcome between-person variability in attractiveness due to simple identity.
 Facial attractiveness is, to an extent, more about what you have, rather than what you do with it. However, we have uncovered here interesting caveats to this overarching and consistent finding. An increased skill level in applying cosmetics seems to offer a larger increase in attractiveness than self-applied cosmetics does—larger effects were clear when a professional makeup artist applied cosmetics. 
Furthermore, we have shown cosmetics affect faces of varying levels of attractiveness differently, particularly within a sample of faces with lower variation in attractiveness between individuals. More attractive individuals simply have less to gain from using cosmetics.
 These findings have theoretical implications for attractiveness research.
 Cosmetics is perhaps the most common form of modification of facial appearance, and we have shown that the currently reported literature, with its reliance on professionally-applied cosmetics, highlights an effect that does not seem achievable through everyday use.
How cosmetics affect attractiveness is a growing literature, and many studies use professionally-applied cosmetics as a means to examine this change. 
We have shown that professionally-applied cosmetics seem to explain a larger proportion of variation in attractiveness judgements than self-applied cosmetics, a category which the vast majority of cosmetics users fall under.
Cosmetics is big business in mainland China and growing. Data from China’s National Bureau of Statistics suggests total retail sales of cosmetics in China in 2018 exceeded RMB 260 billion and a year-on-year growth of almost 10%.
The size and growth of the Chinese cosmetics market has not gone unnoticed by the authorities. The PRC authorities are now overhauling the system to better regulate the cosmetics industry.
The Regulations on Hygiene Supervision of Cosmetics are the most important and also primary regulation that currently governs the production of cosmetics and the operation of cosmetics companies in China. 
As the Current Regulation was passed a long time ago (actually when there was still a Soviet Union) and a lot has happened in China ever since, it is more and more obvious that the Current Regulation is too outdated to deal with new issues that continue to emerge in the cosmetics industry.
The Chinese authorities have taken measures to improve the regulatory framework under the Current Regulation to meet changing needs of the market and also of an industry that has evolved towards increasing complexity but the time is nigh that the Current Regulation  is now ripe to bow out after almost thirty years since first being published
The much awaited second draft of Regulations on Supervision and Administration of Cosmetics was circulated for comment amongst cosmetics industry associations and stakeholders back in August 2018. 
A final draft is anticipated to be issued in the near future and when this happens it will replace the Current Regulation.
With a total of 72 articles the Second Draft is far more comprehensive than the Current Regulation which consists of only 35 articles.
 Accordingly, the Second Draft provides a more detailed and practical regulatory framework that better fits the market realities of China in 2019.
Reports suggest the main drivers for the authorities were to simplify the administration but also encourage technological innovation. 
The Second Draft has adopted a classification management system for the administration of cosmetic new ingredients and also for cosmetic products which is based on different perceived risk levels. 
This aims to balance consumer safety on the one hand but on the other to ensure that regulation is not an overly burdensome constraint and thereby still allow for innovation.
Currently, prior approval must be obtained from China Food and Drug Administration for the use of any new ingredient, either natural or synthetic, if this ingredient has not already been used in the manufacture of cosmetics in China.
The Second Draft provides that new ingredients (except for ingredients used for antiseptic, sunscreen, colorant, hair dye, skin whitener and other higher risk ingredients) will be admitted on a CFDA filing basis rather than requiring approval. 
High-risk new ingredients will still be subject to pre-use registration with CFDA. After registration or filing, the applicant shall report regularly for three years to CFDA as to the use and any safety issues related to the new ingredients. 
If a new ingredient results in safety concerns during such three-year period then the CFDA will revoke its filing or registration. If the three year passes without incident then the new ingredient will be included in the catalogue accepted for use in cosmetics production in China. 
Cosmetics companies have long been frustrated by restrictions on the import of non-special use cosmetics into China.
The Chinese authorities have simplified the import of non-special use cosmetics by starting a pilot program in Shanghai Pudong New Area in 2017 to allow for a filing only process. 
This Pudong pilot scheme was extended on a nationwide basis in 2018.
The Second Draft further clarifies that non-special use cosmetics, either manufactured domestically or imported, only require filing with the competent CFDA.
This new policy will greatly simplify the process by which foreign cosmetics can be imported into the Chinese market. 
This will lead to the purchasing cycle for imported cosmetics being shortened and this will also lead to lower logistics and warehousing costs for foreign cosmetic companies.
Special use cosmetics will still be subject to registration before being allowed to be manufactured or imported into China. 
However, the scope of what constitutes special use cosmetics in the Second Draft has been narrowed from ten categories under the Current Regulation to five categories going forward. 
The special use cosmetics categories include: 1) hair dye products; 2) hair perm products; 3) spots removal and skin whitening products; 4) sunscreen products; and 5) other products which claim a new function.
 Products for hair nourishment, hair removal, breast shaping, fitness, and deodorizing have been removed from the list and are now considered to be ordinary cosmetics and therefore only need a filing.
The Current Regulation sets out only the most general of requirements for cosmetics manufacturers in that they are required to conduct hygiene quality examination of products before market launch.
 The Second Draft requires cosmetics manufacturer to appoint a responsible person in charge of safety and quality. 
The responsible person must have specialist knowledge for medicine, pharmacy, chemistry, toxicology, chemicals and biology and have at least five years working experience in cosmetics manufacturing or quality management. 
The Second Draft provides that applicants for cosmetics registration or filing must carry out a safety assessment of the products before the application. 
The Chinese government has taken a tough stance against the illegal use of forbidden substances in cosmetics. 
The Second Draft provides the CFDA may carry out supplementary tests if current tests are considered insufficient to guard against adulteration or illegal use of restricted or forbidden ingredients in cosmetic products. 
The Second Draft provides a number of new methods by which the CFDA can administer and supervise cosmetic products and cosmetic manufacturers. 
The guidelines cover the whole manufacturing process, market entry and post-sale administration for the cosmetics.
The Current Regulation has attracted criticism for not providing legal grounds for the CFDA to take a more proactive approach to regulation and supervision on imported cosmetics and overseas cosmetics manufacturers.
The Second Draft vests in CFDA the power to carry out overseas on-site inspection in respect of manufacturers of imported cosmetics in order to ensure the manufacturers have met Good Manufacturing Practice (GMP) requirements and to ensure the registration or filing documentation submitted by importers are true and valid.
In addition to the traditional measures of administrative penalties in the case of production quality problems the Second Draft also enables CFDA to have more weapons in their arsenal to police problematic cosmetics manufacturers.
These new powers of the CFDA include the ability to issue safety warnings to the public, ordering mandatory product recalls, reviewing and copying relevant documentation (contracts, bills and ledgers etc.), sealing up and seizing potentially harmful cosmetics and ingredients, and closing down production or distribution sites involved in illegal activities.
 The Second Draft also sets forth a credit system established by CFDA for cosmetics manufacturers and distributors.
Manufacturers and distributors with bad records will invite stricter supervision and be subject to increased numbers of unannounced spot checks.
The Current Regulation sets strict principles regarding the labelling of cosmetic products. In particular, the packaging, labelling and instructions for cosmetic products are prohibited from carrying medical terms or indicating any curative effect.
The prohibition against the use of medical terms does continue in the Second Draft but it is unclear in the draft as the prohibition applies only to the “label” of the cosmetic products but there is no definition of “label”.
 Based on the context of the Second Draft and considering the legislative intent we are inclined to interpret “label” in a broad sense. Therefore, we assume this prohibition will also cover packaging and instructions for cosmetics products.
The Current Regulation also provides a series of principles that must be followed when advertising cosmetics products. 
These include, amongst others, a prohibition on the use of any false or exaggerating or misleading descriptions as to the efficacy of such products. 
The Second Draft further expands upon such scope of the prohibition in respect of labelling of cosmetic products and also advertisements. 
In addition, claims of any function or efficacy of cosmetic products must be supported by sufficient scientific evidence, such as research data, assessment reports or relevant literature. 
Cosmetic manufacturers are responsible for such claims and must disclose a summary of the scientific evidence on designated websites. 
The Second Draft establishes an adverse reaction monitoring system for cosmetics. 
This system requires cosmetics manufacturers and distributors to report to the monitoring authority any reported adverse reaction to their products. 
After the gathering, analysis and assessment of all the materials regarding the adverse reaction, the monitoring authority will provide suggestions for steps to be taken. 
In the case of a serious or large-scale adverse reaction then the CFDA can take emergency measures to prevent an outbreak including suspending manufacturing and sales. Customs is also empowered to block import of such cosmetics. 
China’s massive e-commerce market continues to grow at a staggering rate.
In this regard the Second Draft when read together with the new PRC E-Commerce Law increases the responsibility upon cosmetics e-commerce operators and subjects them to stricter oversight and greater obligations.
Specifically, cosmetics e-commerce platform operators must ensure real-name registration and check necessary qualifications of cosmetics retailers that operate on their platforms.
 They must also promptly put a stop to any activities in violation of the Second Draft and report to the competent authority.
Offline retailers are also subject to increased responsibility. 
Operators of centralized cosmetics stores, store counters for cosmetics and organizers of cosmetics trade fairs are also required by the Second Draft to meet a range of management obligations, including pre-entry examination as to the qualifications of the participating cosmetics operators, post-entry inspection of participating cosmetics operators on a regular basis and promptly stopping and reporting to the competent authority any activities that violate the Second Draft. 
E-commerce platforms and offline operators that fail to perform abovementioned duties may be subject to fines of up to RMB 100,000. 
In addition, hotels and beauty salons that provide or use cosmetics when providing their services shall bear the same responsibilities as operators of cosmetics. 
One of the major complaints after the circulation of the Second Draft was that harsh punishments were overkill. 
These complaints are becoming louder and many claim the increased penalties will turn cosmetics manufacturing into a high-risk industry.
Compared to the Current Regulation the penalties provided for in the Second Draft are far greater.
By way of example, under the Current Regulation, a manufacturer that produces cosmetics that do not meet applicable mandatory standards will be subject to the punishment of confiscation of the relevant products and illegal earnings and may be imposed a fine in the amount of 3 to 5 times of its illegal earnings. 
Under the Second Draft in addition to confiscation of the relevant products and illegal earnings, the manufacturer of the non-conforming cosmetics could also face confiscation of raw materials, packing materials, tools and equipment used for the manufacture and a fine of between 2 to 10 times of the value of the relevant commodity (depending on the exact value); be ordered to stop production and have its cosmetics licenses revoked. 
In addition, the individuals in charge and directly responsible may face personal liability which may include fines ranging from RMB 10,000 to 50,000 and five-year bans from working in cosmetics. 
On balance it seems trite to brand the penalties under the Second Draft as being too harsh. 
Upon careful reading of the relevant provisions it appears clear that the Second Draft not only increases penalties but also provides much clearer guidance as to the application of different penalties depending on the severity of the actions and other relevant factors.
 In this way although the Second Draft increases potential liability it does protect cosmetics operators by providing greater certainty as to what is considered a violation and also guidance as to how punishments will be meted out.
A reading of the Second Draft gives the reader a clear impression that the regulation tends to evolve in the direction of complexity. 
This is very much the case with a regulation that is more than thirty years old.
The PRC regulations in respect of cosmetics are no longer fit for purpose today and do not confront the complex market situation in China — a world of booming Chinese middle class consumers; increasing demand for imported products; online purchases and no doubt a wish to foster a domestic Chinese manufacturing industry.
For overseas cosmetics manufacturers the Second Draft provides more market access; less red tape and more certainty. 
On the negative side the Second Draft will increase obligations and expands the types of measures the Chinese authorities can take. However, none of the measures are highly surprising and the triggers for taking action are also reasonable. 
Few international manufacturers are likely to be anxious about such measures. 
It would be wise for overseas manufacturers to monitor the progress of the new Chinese regulations on cosmetics as they will not bring just increased levels of responsibilities but very welcome market access and clarity.
Worldwide phenomenon, South Korean beauty, or K-Beauty, is always two steps ahead of the game with a skin-first approach to beauty that combines innovative science with generations-old traditions and herbal medicine.?
Home to the 10-step skincare routine where hydration and sun protection are non-negotiable, K-beauty brought us the viral likes of “Glass Skin,” “Honey Skin,” and now “Velvet Skin,” and enlightened us to the world of daily sheet masking and fermented essences.?
From the antioxidant powers of snail slime and ginseng to the healing properties of green tea and bamboo sap, K-Beauty’s “more is more” skincare philosophy brings us high-performing products accessible at various price points.
Heritage brand Sulwhasoo was founded in 1966 when it launched its ABC Ginseng Cream — the world’s first ginseng-based cosmetic product — and has since pioneered over 50 years of research on the Ginseng plant.?
Today, the premier skincare label combines the Asian wisdom of balance and harmony with the time-tested medicinal herbs of Korean “Hanbang.” The First Care Activating Serum EX is Sulwhasoo’s signature product — one bottle is sold every ten seconds.
K-Beauty heavyweight Neogen develops skincare products based on the latest derma-ceutical research and its patented six-core biotechnology, which maximises the powers of natural ingredients.
Its famous Bio-Peels Gauze pads harness the powers of AHA chemical exfoliation and antioxidant resveratrol, while its Real Ferment Micro Essence brightens and locks in moisture with a cocktail of natural ingredients.
Erborian is a half-Korean, half-French beauty brand — need we say more? By combining the best of traditional Korean herbal ingredients, Korean skincare technology, and the luxury savoir faire of the French, Erborian creates sophisticated formulas that improve both the health and appearance of your skin.?
Its do-it-all CC creams are loved in both Asia and Europe, and its Solid Cleansing Oil and Double Lotion are staples in any multi-step skincare routine.
CosRX, which stands for cosmetics, was founded in 2014 with the mission to deliver effective, affordable skincare solutions that focus on formulation and ingredients — its Snail Essence is made with 96% snail mucin.
Its low pH cleanser spotlights the importance of maintaining the skin’s optimal acid mantle (i.e. gentle cleansing without stripping the skin of its natural oils), while its Acne Pimple Master Patches are game-changing.
Famous for its cult-favourite line of Sleeping Masks, Laneige was created by Amore Pacific in 1994 and named after the French word for “snow.”
The Water Sleeping Mask (an overnight moisture-recharging gel mask) and the Lip Sleeping Mask are some of the most-reviewed and top-rated treatments in the world.
AmorePacific is like the Est?e Lauder of Korean beauty, owning nearly 30 of the most well-known K-Beauty labels including Laneige, Sulwhasoo, Etude House and Innisfree.?
Sung-When Suh founded AmorePacific in 1945 with the idea of incorporating green tea from Jeju island into skin treatments, giving birth to the Vintage Single Extract Essence, which is made from handpicked green tea leaves that are naturally fermented in optimal conditions for 50 days.
Other signature products like the Enzyme Peel Cleansing Powder balance tradition with modern science and, most importantly, is one of the most gentle and effective exfoliators on the market.
One of the first K-Beauty brands to break into the western market, Dr. Jart was created in 2004 by dermatologist Dr. SungJae Jung to provide science-driven skincare solutions and cosmetics targeting dryness, sensitive and acne-prone skin.?
Dr. Jart’s first product was the BB Cream in 2006 and the brand consistently produced other hits like the Cicapair Tiger Grass colour correcting line and the Cermidin range.
SU:M37 specializes in skincare made from advanced natural fermentation technology.?
At the heart of its products is a patented compound Cytosis which features over 80 local and seasonal ingredients that are fermented at the optimal temperature of 37 degrees celsius for a minimum of 365 days — some for as long as a decade.?
Its signature Secret Essence is a magical do-it-all potion that firms, brightens, hydrates and tones all skin types.
The History of Whoo is a modern interpretation of traditional Korean royal court beauty secrets using advanced lab ingredients, nanotechnology and premium herbal medicines specifically designed for Asian skin.
Each product features the brand’s Gongjinbidan Complex, a key ingredient derived from an ancient health formula used by Korean emperors and empresses for over 800 years to improve blood circulation.?
The Bichup Ja Saeng Essence is a best selling luxury serum in Asia.
If you left your Halloween costume to the last minute and are relying on your closet’s current contents, a strong makeup look can make all the difference.?
For inspiration, look no further than the SS20 runways, where witchy mascara and graphic eyeliner made for a fashionable take on spooky beauty.
From the clumpy, elongated lashes at Olivier Theyskens, to the angular onyx liner at Gypsy Sport, it’s apparent that a premature Halloween energy took over the runways, even if the mood boards were much broader than ghosts and ghouls.
“I was super inspired by 90s tribal tattoos and KISS the band for this look,” makeup artist Fatima Thomas, said backstage at Gypsy Sport when asked about the look she created using MAC’s Brush Stroke Liner in black.
“This might not be a look for everyday life, but it’s there to inspire people to take risks.” In other words, it’s perfect for Halloween.
When creating the next-level lashes at Olivier Theyskens, makeup artist Issamaya Ffrench accomplished her mission to create “something dark that is still beautiful and elegant,” as she described it.
“I wanted a spidery, fragile length for the lashes, to make it look like an illustration,” she continued. A sturdy hand along with Kryolan lashes, Duo lash glue, and MAC’s Blacktrack eyeliner did the job.
Here, to help you get into the Halloween spirit, more trick or treat-worthy eye makeup looks from the SS20 runway shows.
For a fashion girl, dressing up on Halloween goes far beyond the sartorial.?
It’s a head-to-toe affair—with a heavy emphasis on the former. A quick rifle through her treasure trove of clothes yields an idiosyncratic-chic costume, but it’s when she dips into her makeup bag that the fun really begins.?
Whether stepping into cinematic character or reimagining a spine-chilling classic, it’s a cool-girl calling card to indulge your wildest beauty fantasy over October’s last days.
“On Halloween, it’s about paying homage to traditional characters, but giving them a modern twist!” says editorial makeup artist Grace Ahn, encasing British-Nigerian artist Oyinda’s piercing gaze with two gold stars that flash against her glowing skin, glossy lips, and heavy-metal Marni dress.?
Korean model Hyunji Shin receives a duo of sharp, deconstructed feline flicks and muted brown pout, her dark lengths sculpted into cat ear-like knots, while rising runway star Massima Desire is getting a more-pared back Harlequin treatment, clad in a diamond-print Puppets & Puppets suit.
“I’m a Scorpio with a Pisces moon, so I’m a sad clown in my daily life,” Desire laughs as Ahn defines her eyes with punkish Pierrot liner and swirls soft peach pigment on her cheeks. “I love being a goofball who’s also really into crying.”
Finding a sweet spot between Betty Boop and Jessica Rabbit, Dominican model Anyelina Rosa is a subversive bombshell, radiating cartoonish shine as she slinks around in crimson patent leather Rick Owens boots with matching vinyl red lips.?
As for Belgian beauty Hanne Gaby, she’s breathing new life into the tried-and-true, flesh-eating zombie; Ahn administering painterly bursts of neon-pastels on the lids to play off her tattered powder pink Moschino dress.
Bringing the bewitching and beguiling to life, Ahn dreams up five makeup ideas that will help you lay the drama on thick this Halloween.
Per tradition, Paris Fashion Week was all things to beauty dreamers.?
For the Francophiles, there were looks that captured that elusive insouciance—the Gallic flicks of liner at Dior, the undone ’70s waves at Celine—but also ones that paid homage to the past: Thom Browne’s chandelier-bound Marie Antoinette poufs, for example, transported showgoers back to the 18th century.?
With a flair for the dramatics as a through line, fantastical flourishes were omnipresent: At Giambattista Valli, supercharged complexions were adorned with fresh-from-the-garden florals, while at Dries Van Noten, the Belgian designer paid homage to his co-collaborator Christian Lacroix with ostrich plume-topped updos.
And then there were the dizzying, super-Surrealist cascades of eye crystals at Schiaparelli, which helped close out the nine-day marathon with a veritable bang.?
But of all the mic-drop moments, none was more jaw-dropping—or thought-provoking—than the glass-sharp prosthetic cheekbones and inflated lips at Balenciaga. Here, five standout takeaways from the week.
At Dior, makeup artist Peter Philips embraced a more minimal mindset than he has in seasons past.?
“This is a toned-down version of a French woman’s classic eyeliner,” said Philips of the smooth, slender slashes of pigment along the upper lash line, which didn’t extend all the way to the inner corner for a more pared-back effect.
“Less is more” was also the overarching mood for the hair at Celine, Chanel, and Saint Laurent, where each of the French fashion houses channeled the late ’60s and early ’70s with clean center parts and tousled, languid lengths.
Translucent shine is the new go-with-everything neutral. For proof, look no further than the dewy, crystal-clear lips that came down the runway at Mugler, Off-White, and Giambattista Valli.
But if it’s a dose of juicy color you crave, one fell swoop of Pat McGrath’s saturated Lust: Gloss will do the trick, as evidenced by the bright pink pouts at Louis Vuitton.
Or, you can make like Chanel’s global creative makeup and color designer Lucia Pica, who painted lips coral pink, blending out the outer edges for a diffused effect, and added a vinyl-like top layer.?
“It almost looks as if the girls have been eating a strawberry,” Pica said backstage.
Partially obscured by plumed fringe, there were Blade Runner–inspired “brushstroke masks” running across gazes in gold, black, and white at Dries Van Noten.?
And bringing sparkle to the eye-level equation, there were meteor-shower-inspired dustings of metallic silver glitter and loose octagon sequins at Off-White, as well as four shimmering gold eye looks at Valentino that utilized aureate gems and heavy-duty falsies. Most extra of all? That would be Schiaparelli, where makeup artist Erin Parsons created a wide array of Surrealist crystalized gazes ranging from a silver glittered “rhinestone cowgirl” look to a gradient rainbow “poison dart frog” one.
"I'm not a foundation person," is how?most?of the team ELLE prefaces their foundation picks. 
Blame BB creams, tinted moisturizers, and the prevalence of no-makeup makeup, but there's a recent reluctance to come out as a daily foundation wearer.
However, unless you are born with genetically perfect skin, a great foundation (you know, one that covers but?doesn't?feel like a mask ) is an makeup bag essential for everyone. 
So, let's play pretend-perfect-skin with 11 of ELLE's favorite foundations—and a few foundation-like BB creams snuck in—below.
However, unless you are born with genetically perfect skin, a great foundation (you know, one that covers but?doesn't?feel like a mask ) is an makeup bag essential for everyone. 
"I’ve been obsessed with this foundation for years. It requires very little blending and the creamy formula looks exactly like actual skin. 
Well 'actual skin' if it were spotless and glowing. 
The price tag hurts, but I build up the coverage lightly and slowly so none goes to waste. 
I also only use it on special occasions and wear a more?affordable CC cream?on an average day."
"The foundation that singlehandedly got me through high school and my accompanying?acne,?Clinique's Acne Solutions Liquid Makeup,?is smooth, oil-free, and unobtrusive. 
It provides long-lasting coverage while also remaining light and blending seamlessly with?my skin tone."
“My new favorite foundation is the?Guerlain L’Essentiel Natural 16H Wear Foundation. 
I must be honest, I’m not normally a heavy wearing makeup girl because I prefer a natural look?and?it’s hard finding foundations that match my complexion. 
But I love this one! It’s super-light and still feels natural without being too heavy and looking caked on. 
For those life events when I want to be the *best* version of myself, this is my go-to.”
"Two people have stopped me on the street recently to ask about my skin. I credit it to a few things, including drinking a lot of water,?Dior Airflash Spray Foundation, and saying a spell during a full moon. 
I like to spray Airflash onto my hand then buff it onto my face with an Artis brush so the coverage is lighter.
 It never feels like I have foundation on but perfectly evens out my skin so I can skip cover up, which rules."
"In a perfect world, I wouldn’t have to use foundation to cover up my acne scars or hide any active breakouts. Luckily,?Anastasia Beverly Hills Luminous Foundation?does a pretty good job of hiding my impurities all while making me look all fresh-faced and radiant with just one pump—yes, it’s that good!"
"All I need in this life of sin is a full-coverage foundation that feels lightweight. 
Charlotte Tilbury's magical formula manages to do both, while keeping my oily face matte and poreless."?
"I just graduated to using foundation as part of my regular makeup routine last year.
 I've always been a skincare girl, so my goal was never to use foundation as a coverup. 
I really needed a formula that would act as a second skin—literally. Something lightweight that made for a good base to layer on blush and contour, and still allowed my skin to shine through (I haven't adopted an eight-step regime for nothing). When I discovered this formula—thanks to my friend, makeup artist Katie Jane Hughes—I was hooked! And the best part is that it's packed with luminizers, so I've got a dewy glow, all year-round."
"I've been using BareMinerals products since high school—I had acne then, and it didn't break out my skin.
 I still use it today because I love the solid coverage from a light powder. 
I switched to the matte version because my skin tends to be oily in the summer and this keeps the shine down. 
Truly a solid, essential product in my makeup kit that has held up for years."
"ELLE editors love this foundation and I'm one of them. 
It's the best for full coverage and creating a flawless complexion. I use this for nights out on the town when I want to impress."
For girls that feel edgy one day and flirty the next, Mirabella Beauty aims to create clean, mineral makeup, from foundations to eye shadows, that are free of parabens, talc and lead in an array of beautiful shades to fit all skin tones and types.
 From high-definition, full-coverage liquid foundations to cc cr?mes and even full coverage powder foundations, Mirabella Beauty has a foundation to fit every women’s needs.
Mirabella’s heaviest full coverage matte foundation, Invincible HD Anti Aging Foundation comes in five versatile shades.
 Each shade can be worn alone or blended for the perfect skin match. 
Invincible Foundation is the best mineral makeup for Rosacea as its high definition formula smoothes and refines skin for a flawless finish. 
When searching for the best mineral makeup for acne prone skin, Mirabella’s medium-coverage foundation, Skin Tint Cr?me is a great solution.
 Made with skin-loving ingredients, this face foundation makeup glides on to a silky luminescent finish.
For girls and women looking for a less heavy coverage, Mirabella Beauty offers two additional mineral makeup foundations, one in the form of a cc cr?me and one full coverage, lightweight foundation makeup. 
The cc cr?me features soothing and hydrating ingredients like apple and bamboo waters that keep skin fresh and looking young. 
For this reason, the cc cr?mes perform well in warm temperature and stay beautiful on the skin, making this foundation the perfect product for Coachella makeup. 
Finally, Pure Press powder face foundation makeup is infused with natural vitamins and minerals and can be worn alone or used to set cream and liquid foundations.?
2018 is turning into the year of foundation. 
With new lines emerging with innovative formulas and old favorites expanding their collection, it has never been a better time to be a makeup lover. 
Whether you’re looking for something light to simply help even out your skin tone, you’re needing full coverage, or anything in between there’s plenty of products for whatever makeup mood you’re in. 
The best part?
 Many major cosmetic companies are expanding their shade range, making it easier than ever for everyone to find exactly what they’re looking for. 
Here are our top picks for the next time you’re looking for a new face product.
This foundation has been heralded for having shades for even those with the most difficult to match complexions. 
It also boasts 24 hour wear, giving your face a natural look while still being full coverage.
 With 56 shades to choose from there are plenty to experiment with to find your perfect shade.
If a lightweight foundation with stage production quality sounds like all your dreams coming true, you’ll need to check out this Dior foundation. 
This formula was made to be worn not only on your face, but also your body even in high temperatures and humid environments.
For those that battle oily skin every day, this foundation boasts a full coverage, matte wear that lasts all day. 
It’s so full coverage, in fact, that you only need a small drop to give your skin a flawless, airbrushed look. 
With so many shades to choose from, you’ll definitely want to head into Nordstrom to get matched with your perfect shade.
Who doesn’t want more luminous skin and a more even complexion? 
This foundation by Clinique was formulated by dermatologists to give you better skin even on the days you go bare faced. 
This medium-to-full coverage foundation includes SPF, making your morning routine that much quicker, while also helping to improve your skin.
The hunt for a foundation that’s full coverage and combats shine all day is over.
 Make Up For Ever’s Matte Velvet line is great for all skin types and boasts 24 hour wear. 
It’s perfect for anyone wanting buildable coverage that’s good for your skin.
Finding a good vegan foundation can be a struggle. 
Cover FX has delivered with this full coverage, long lasting foundation. 
This brand prides itself on providing “clean” beauty products, free from ingredients that can be damaging to not only your skin, but to your overall health.
 With hundreds of rave reviews online from happy makeup lovers, you’re sure to find one you love in this impressive 40 shade line up.
If you haven’t heard of Rihanna’s record breaking beauty line, you are missing out.
 Her line of foundations were created to be inclusive of women on both ends of the shade spectrum – the ones who typically have the hardest time finding a color match in other lines.
 With 43 shades in the lineup, and a three-step guide to finding your match on Sephora’s website, it’s never been easier to find the perfect foundation.
Many of the foundation’s we’ve been talking about have been more on the full coverage side. 
But what about those who want a more natural look while still covering minor imperfections in their skin?
 Have no fear – Tarte has got you covered! Their vegan formula with their signature Amazonian clay goes on smooth and won’t leave you looking cakey at the end of a long day.
For those looking for flawless coverage that gives your skin the appearance of wearing nothing at all, you’ll want to check out Too Faced. 
This 35-shade range provides plenty of nuanced colors to give you the best coverage for your skin’s unique coloring. 
It’s also known for being great for photos and not giving your skin the white cast that so many other foundations can be guilty of. Give this one a whirl, and get your selfie on, too!
But last week, trace amounts of asbestos — a known cancer causer — were?found in concealer as well as sparkly makeup marketed to kids at Claire's, a reminder that?toxic chemicals and compounds still lurk in beauty products.?
In March, Claire's also?voluntarily recalled some of its eye shadow and face powder?after asbestos was found in those products as well.
The issue isn't limited to cosmetics:?The FDA recently warned?about dangerous bacteria in a no-rinse cleansing foam used by hospital patients, alerted tattoo artists about ink contaminated with microorganisms, and found yeast in Young Living essential oils moisturizer.
In part, these problems arise because US beauty products are largely unregulated.
"The law does not require cosmetic products and ingredients, other than color additives, to have FDA approval before they go on the market," the?US Food and Drug Administration?(FDA) notes.?
Some toxic ingredients (like asbestos) are inadvertently added during the manufacturing process, while product makers put others in purposefully to help with absorption, shine, shimmer, or a non-greasy feel.
 Studies suggest that chemicals from the products people put on their faces and bodies can show?up later in urine.
 Certain compounds, especially when mixed together in the body, might?up a person's odds of developing cancer?or mess with their?reproductive ability.
But it's nearly impossible?for consumers to determine what's in cosmetics even by reading the labels, since many compounds can be considered trade secrets and hide in the "parfum" or "fragrance" ingredients on a list.
Alec Batis, a former research chemist who once made hair dyes for the?L'Oreal group, is an expert in the risks and benefits of chemicals used in beauty products.?
Batis, who now works as a paid consultant for beauty companies and recently appeared in a?documentary?called "Toxic Beauty," told Business Insider that people should be concerned about some chemicals in products like soap, shampoo, and perfume. But not every formulation is dangerous.
"It's not about hating chemicals," Batis said. 
"Let's understand what this stuff really is."
Here's a look at 11 problematic ingredients that are near-universal bathroom vanity staples.?
Phthalates help make plastics durable and flexible.
 They're used in?raincoats, flooring, hair spray, nail polish, perfume, lotion, shampoo, aftershave, food packaging, and toys, among many other items.?
When it comes to makeup, the FDA says?on its website?that diethylphthalate (DEP) is "the only phthalate still commonly used in cosmetics."
At least one phthalate can cause cancer, according to the?National Institutes of Health.
 There's also evidence that the chemicals can also?mess with reproduction?and child development.?
Batis said he'll wear some fragrance when he goes out, but he washes it off before bed.?
"We don't know the long term effects, and we have to be smart about it," he said.?
The chemicals are meant to prevent mold and bacterial growth, but it's not clear yet how they?impact human health?at low levels.
Many cosmetic makers have switched to "paraben-free" formulations, but Batis said that doesn't mean they're better.
"They switch to other [preservatives], for example, methylchloroisothiazolinone and its sister compounds," he said. "
And I'm thinking, 'Wow. You're switching to that, which is a known sensitizing allergen.'"
Frequent use of?sensitizing allergens like methylchloroisothiazolinone can cause lesions and a scaly red rash?in some people.
According to the FDA, 1,4 dioxane "is a potential human carcinogen."
 It sometimes shows up in beauty products that contain detergents, foams, stabilizers or solvents.?
The FDA recommends that manufacturers use a vacuum technique so that the cancer-linked byproduct can be avoided. Batis agrees.?
"The manufacturing process should be standardized to vacuum," he said. 
"There's so many simple solves for some of these things."?
Asbestos, a known cancer-causer, was found in makeup sold at Claire's twice this year.
"It wasn't surprising to me, because there's no regulation," Dr. Shruthi Mahalingaiah, a gynecologist at Boston Medical Center,?said at the time.
Coal tar dyes can irritate the skin, and in severe cases, make people go blind.
"There are no color additives approved by FDA for permanent dyeing or tinting of eyelashes and eyebrows," the FDA says in its warning on?eye cosmetic safety.
Most coal tar hair dyes today are made with petroleum, but they?can still cause harm. 
The FDA?suggests keeping hair dye away?from your eyes, and says "do not dye your eyebrows or eyelashes."
The first step to applying like a professional is to choose the correct type of foundation for your skin type and secondly, the correct color.
If you have oily skin, go for an oil-free to avoid looking shiny half way through the day, or if you have dry skin, choose an oil-based to keep your skin moisturized.
For a foundation that holds the whole day, go for a long-lasting base with a slightly thicker medium.
 These types tend to stay put for an extended period of time without the need for re-application.
For a lightweight, air-brushed look, go for a mousse or powder, which offers a very thin layer of cover and sheen-like look.
 This type is best for people with flawless, blemish free skin as it does not cover marks well, but rather creates a perfect finish.
Choosing the correct color for your skin is vital to avoid looking like you have foundation on or having a ‘jawline line’.
The best way to choose the correct color is to test the foundation on your jawline in bright daylight.
 If the color disappears into your skin tone, the color is correct. If you can see the foundation on your skin, it is probably too dark or light. 
Expert tip! If you can’t afford to splurge on foundation, get a beauty adviser in the store to help you pick the perfect color, and ask for a sample to take home.
It is important to make sure your skin is clean and moisturized before applying foundation. 
Cleanse your face, moisturize and wait for five minutes to let the moisturizer to sink into your skin before applying the foundation.
If you have large pores, use a primer before applying foundation to fill in pores and make them appear smaller, as well as help give you a matt finish.
A primer is also a good layer to add if you want your makeup to last the whole day or night.
There are a few ways to apply foundation and these depend on the amount of coverage you desire.
If you are looking for light coverage for an everyday look, professional makeup artists suggest using your fingers to dab a little foundation on spots, marks and blemishes and simply rub it in evenly.
If you are looking for more coverage, use a sponge and blend the foundation in all over your face, working from the middle outwards. 
Be careful of applying too much foundation though — make sure the first layer is blended in completely before applying a second layer.
Concealer is a great way to cover those stubborn marks or blemishes just won’t hide. Apply your concealer after as applying it before can create a cakey look. 
Using a small, pointy brush, dab some concealer on the darkest part of under-eye circles to get rid of those bags and shadows or use a cotton bud to dab some concealer onto spots and marks that need to go!
Expert tip!?If you suffer from problem skin, avoid using foundation too often as this tends to clog the pores. 
Find a concealer that has medicinal properties that help to dry out spots and pimples and use this instead — it will hide the spots and dry them out at the same time.
To create a flawless, airbrushed look, finish application with a lightweight powder. New translucent powders on the market help to reflect the light help skin glow and reduce shine, so take a large brush and dust some on in a ‘W’ motion. 
Begin at your hairline on one side, swoop the brush down towards your cheek bone, back up to the bridge of your nose, lightly back down the other cheek, and then up again to the opposite hairline
The mere word ‘foundation’ used to conjure images of the thick, cakey makeup we used to see pasted on faces of the older generation. 
However it has come a long way since then, evolving to become a sheer, svelte layer that is easy to apply and makes your skin look flawless. 
There are myriad types on the market today, from thick,?long-lasting cr?me foundations?to powder-light mousses that are barely there. 
The trick to ending up with flawless skin is not only to choose the correct for your skin type, but to apply it in a way that will leave you looking ready for the catwalk.
Foundation is a liquid makeup applied to the face to create an even, uniform color to the complexion, cover flaws and, sometimes, to change the natural skin tone.
 Lipstick is a cosmetic product containing pigments, oils, waxes, and emollients that apply color, texture, and protection to the lips.
 Mascara is a cosmetic commonly used to enhance the eyelashes. It may darken, thicken, lengthen, and/or define the eyelashes.
For thousands of years the fashion conscious have used make-up to get their look just right, and keep up with fast-moving trends. 
Now, the global beauty industry is experiencing a revolution driven by South Korea. Say hello to K-beauty.
Young people in Western countries have become infatuated with K-pop - Korean pop music - and Korean soap operas.
Many Korean celebrities and pop stars, including the seven-member boy band BTS, are known for their signature looks.
But it's not just Korean entertainment - in the last 18 months, there has also been a rise in Korean beauty trends coming over to the West.
In 2017, South Korea's beauty industry was estimated to be worth just over $13bn (?10bn), according to retail researchers Mintel.
The fascination with Korean cosmetics is due to how innovative they are, says Marie Claire's digital beauty editor Katie Thomas.
South Korea's beauty industry is typically about 10-12 years ahead of the rest of the world, she says.
"It's not that there's been a big boom, we're just catching up with them essentially,  the expansion of Instagram and beauty blogging."
Before even putting any make-up on, Koreans put in a lot of effort to take care of their skin.
"It's sort of ingrained in Korean culture from a very young age to look after your skin," Ms Thomas says, explaining that the Korean ethos is to ensure that you have good skin, rather than needing foundation and other products to cover up unsightly blemishes.
You might be used to the typical daily three-step routine of using cleanser, toner and moisturiser before applying make-up, but in South Korea, skincare regimes range from seven to 12 steps, with a focus on hydrating the skin using gentle, natural ingredients.
Some people would see it as excessive, but the fact is, you're feeding your skin with these incredible ingredients. It's so different in the UK [in comparison]," says Ms Thomas.
Much more research is carried out into new products in South Korea than in other countries, she says, because there are so many competing brands, each trying to be the best.
"The Korean beauty industry doesn't shy away from introducing new, unique ingredients to their formulas that would never be considered in the West," says Karen Hong, the founder of K Beauty Bar, a concession stand for Korean beauty products found in Topshop's flagship store in London's Oxford Street.
“Unique ingredients such as...? "Snail mucin for moisturising, pearl for brightening, green tea for oil control and propolis from bees for soothing and nourishing," she reels off.
In the US, 13% of 10 to 17-year-old girls are interested in trying K-beauty products, and 18% of 18 to 22-year-old women have used these products.
According to Mintel's global beauty analyst Andrew McDougall, Korean beauty trends have grown in popularity thanks to "clever digital marketing strategies" on social media that have gained the interest of Western beauty influencers, bloggers and journalists.
Consumers' interests are piqued by colourful packaging, as well as reviews and demonstrations on Instagram and YouTube, he explains.
"It's consumers who are more informed and do their own research, and it's influencers who put them on the K-beauty path in the first place," says Mr McDougall.
Katie Thomas agrees: "That K-pop fun quite cartoony approach is very much part of their industry. But it does do very well. People do buy into fun packaging - things they can take a picture of on their bathroom shelf."
Some products can be found in Topshop and TKMaxx, but other than that, most British consumers can only buy these products online.
YesStyle.com is one such company, and it sees Korean make-up as big business.
The Hong Kong-based e-commerce firm carries more than 150 Korean brands, and it expects sales of K-beauty products to top $25m in 2018.
Its founder Joshua Lau says the website's success has been down to reviews from verified buyers that give Western consumers the confidence to take a chance on new items.
YesStyle's beauty editor Romy Rose Reyes says that Western consumers have been intrigued by the "Chok Chok" no make-up make-up look, where the aim is to have "dewy and bouncy skin with an extra glow".
According to Ms Reyes and Ms Hong, looking "natural" and "youthful" is in, and the matte look favoured by European and US markets is now out.
Western cosmetics makers have been taking notice too.
"We see some Western brands take on a few of these skincare steps into their own regimes," says Marie Claire's Katie Thomas.
"For example, Yves Saint Laurent has cushion foundation and cushion blushers. It's a bit less scary for consumers - an easy way into K-beauty with a known brand."
This summer, Primark launched its K-Pop range of cosmetics, which sold out quickly.
Primark told the BBC that it was inspired by a "huge trend" it saw based on skincare innovations from South Korea, and it is continuing to stock face masks.
"We found this was a range that really worked for the younger consumer, who was not necessarily after serious skincare," a company spokesperson said.
So is it just a fad, or is the K-beauty trend likely to last?
Ms Thomas thinks it's here to stay, because young people are very concerned about the environment, and how damage to it affects humans as well as plants and animals.
"People are becoming more attuned to what is happening to their skin - there's so much pollution that gets into our skin that we don't know about," she says. 
Anything related to environmental damage is very much coming over to the Western market.
But while much of this applies to women, in Korea cosmetics is big business for both male and female consumers, so is K-beauty likely to take off with men in the West?
"In Korea there is a different attitude amongst men towards skincare and make-up - they're not afraid to express themselves as long as they look and feel good, especially the younger generation. But this isn't a trend that has reached the general male population in the West yet," says Karen Hong.
Mintel's Andrew McDougall agrees.
"Men in the West are increasingly becoming more active consumers in the beauty and personal care area, though there is a long way to catch up," he says.
He points to Chanel's recent launch of a make-up line targeted at men called Boy de Chanel - the company chose to debut the products in South Korea, rather than its native France.
Mr McDougall also adds that he doesn't wear make-up or use a fancy skincare routine himself.
But while much of this applies to women, in Korea cosmetics is big business for both male and female consumers, so is K-beauty likely to take off with men in the West?
"In Korea there is a different attitude amongst men towards skincare and make-up - they're not afraid to express themselves as long as they look and feel good, especially the younger generation. 
But this isn't a trend that has reached the general male population in the West yet," says Karen Hong.
Mintel's Andrew McDougall agrees.
"Men in the West are increasingly becoming more active consumers in the beauty and personal care area, though there is a long way to catch up," he says.
He points to Chanel's recent launch of a make-up line targeted at men called Boy de Chanel - the company chose to debut the products in South Korea, rather than its native France.
Mr McDougall also adds that he doesn't wear make-up or use a fancy skincare routine himself.
2018 Winter Olympics may be over, but the world is still buzzing about all things South Korean. 
South Korea has continued to emerge as one of the top drivers for global economic and fast moving consumer goods industries, which is inspiring many new trends in other countries.
South Korean culture comes in many forms – in song, movie, television, food and distinctive fashion.
The overall culture and consumption of the population in South Korea is very much influenced by popular actors and singers endorsing the products.
Fans are more likely to buy products that their idols are endorsing, which causes major market shifts and can increase consumption significantly. 
Moreover, as the actors and singers become popular overseas, so do the products that they promote. 
As a result, manufacturers compete to get the most popular representatives for their brands, and this forms a major part of their overseas expansion strategy.
There is no doubt that many brands and manufacturers have utilised the Olympics to catapult their products onto the world stage during South Korea’s moment in the spotlight. 
This can be seen especially with the growth of K-beauty products in the U.S. market.
In 2015, South Korea’s beauty exports to the US grew 59%, reaching usd$207 million. 
Social media has propelled the growth of K-beauty in the US by turning skin care and makeup routines into creative outlets for self-expression. 
The rapid proliferation of social media since the late 2000s has provided fashion-forward individuals with a myriad of platforms to spread the gospel of K-beauty.
Makeup and skin care- loving Koreans took to YouTube, blogs and Instagram to share their interests with the rest of the world.
Product reviews and makeup tutorials engage and educate viewers, while “transformation videos,” in which YouTubers alter themselves into recognisable celebrities, highlight the astonishing power of makeup and excite the viewer’s imagination.
Social media celebrities have been more successful at promoting Korean skin care than corporate or government-sponsored marketing campaigns because they focus on the topics that truly excite them, while also providing compelling video and photographic evidence of their personal skin care journeys.
As the generation that inspired the term “hipster”, many millennials passionately embrace individualism. 
These fashion-forward children of the information age investigate products online before they shop, relying on reviews and tutorials to appraise product efficiency; thus they readily seek out niche and foreign brands.
Because Korean skincare transcends the traditional Western cleanse-tone-moisturise routine, K-Beauty’s myriad of products like serums, essences, ampoules and masks can be customised to an individual’s exact skin care needs and preferences. 
The array of products appeals to millennials who are paying more attention to their skin’s unique needs than previous generations.
Many millennials respond strongly to novelty and emotional appeals, making room in their bathroom cabinets for products with cute designs, alluring scents, transforming textures and on-trend ingredients which set them apart from mainstream American beauty products. 
This drives interest in brands like Tony Moly, whose products are packaged to look like whimsical cartoon fruit and animals, and Missha, whose collections include imaginative collaborations with Hello Kitty and D.C.’s Wonder Woman. 
The fun of K-beauty appeals to even the youngest millennial consumers; Leah Park, co-owner of Korean Beauty Retailer Choc Choc in Chicago, remarks that customers as young as 10 years old come to her store to purchase cute products like sheet masks printed with animal faces.
South Korean brands stand to gain significant market share in the U.S. teen and preteen market with endearing product design and packaging.
Korean brands like Innisfree and Skin Food have a “natural” angle to them, aligning well with increasing millennial interest in natural, organic and sustainably sourced products across all areas of beauty and personal care. 
Euromonitor International’s 2015 Beauty Survey found that 13% of U.S. respondents seek out natural or organic colour cosmetic products and 20% seek out natural or organic skin care products.
Thus, Korean beauty brands hoping to enter the U.S. beauty market would do well to emphasise their products’ gentleness and natural ingredients further.
There's face powder in panda palettes, hand gel in gummy bears and bubble tea sleeping packs.
Often packaged in bright colors and decked out with cartoon characters, Korean beauty products are too cute to ignore, but they also provide some health benefits.
It's "skin-tertainment," said Christine Chang, who co-created the Glow Recipe brand to bring Korean beauty products to the American market. 
She and partner Sarah Lee travel to South Korea multiple times a year to find new products and are repeatedly "blown away by the new innovation in the market."
Complete Korean cosmetics shopping guide 
The Korean beauty market is among the top 10 around the world, with an estimated worth of over $13.1 billion in sales in 2018, according to Mintel, a global market intelligence agency. 
Facial skin care products alone make up half of the total market share and are projected to reach $7.2 billion by 2020.
 And one in five facial skin care launches in South Korea, the agency reports, is actually a mask.
"For a long time, France and Japan were considered a symbol of cosmetics business around the globe," said Ryan Park, who founded the Korean beauty brand Whamisa in 1999.
"Korea was able to catch up with them within a very short time thanks to the balance of its accumulated fundamental industry, chemistry, bioscience and Korean Wave culture."
K-pop group record breaking album conquers three continents
The Korean wave, called "hallyu," is about the spread of South Korean pop culture and how all things Korean -- food, dramas, makeup, movies and music -- have propagated throughout the world through social media and online platforms.
 A lot of this wave radiates off of the music, K-pop, with artists like PSY, Wonder Girls and BTS whose edgy look, style and sound attract global fans.
Simply put, consumers want the skin of Korean celebrities, who supposedly use it too, said Dr. Soyun Cho, a dermatology professor at Seoul National University.
The Korean brand Whamisa was founded in 1999.
E-Commerce Guide by CNN Underscored: Your guide to using Korean skin care products
Korea is also one of few countries with "functional cosmetics," Cho said, a label allowed by the Korea Food and Drug Administration for anti-wrinkle, elasticity-boosting, pigment-fading and sunscreen properties. 
This has fueled more research for better products, she said.
"Korea has become the test bed of many world-famous cosmetic companies," said Cho, who has studied the behavior behind cosmetic use in Koreans. 
"Korean consumers are very knowledgeable about different cosmetic types and ingredients, and they are picky. 
They are early adapters of new products, and cosmetic trend comes and goes at a very fast rate in Korea, partly due to the ubiquitous high-speed internet and heavy use of social media.
"Young Korean women are very keen to try the new trend, and they don't want to be left out of the loop when all their friends are using a new product."
To showcase new Korean beauty products, Chang co-founded Glow Recipe in 2014 after working at Kiehl's in global skincare marketing and at L'Oreal in Korea and the US. 
"A key strength of K-beauty products is the experience," she said. "Formulas often have enjoyable, unique textures or flexible usage methods."
Chang cites the use of aloe instead of water for intense nourishment, applying "rubber masks" -- instead of paper sheet face masks -- for better nutrient absorption and fermented botanicals for more efficient absorption into the skin.
Fermented botanicals contain micro-organisms that release enzymes that ferment and break down molecules into the raw material, resulting in the creation of new substances that benefit the skin, explains dermatology professor Cho. 
Another example of innovation is the combination of beauty balm cream, BB cream, with an air cushion compact, Cho said.
Although these creams were created in Germany, Korean companies popularized the merging of foundation, moisturizer, anti-aging cream, whitening agent and sunscreen in one product.
The air cushion compact "wicks the formula off a sponge and effortlessly applies evenly onto the face for that dewy, no-makeup makeup look," Chang said.
Many of these products follow that "baby-like" look with "cosmeceuticals," Cho said, combining cosmetics and therapeutics with such natural ingredients as traditional Korean herbs and plant extracts. 
Snail slime has also been a popular component in many Korean beauty products, because it reportedly improves skin imperfections like scars, wrinkles and acne.
Glow Recipe worked with Whamisa on a green tea line with antioxidants and botanical extracts that melts makeup and removes pore-clogging impurities. 
Its star product, the Watermelon Glow Sleeping Mask, sold out eight times with the French cosmetics giant Sephora last year and had a wait list of over 20,000 on the Glow Recipe website.
The Soko Glam e-commerce site helps people find Korean skin care and opened a pop-up shop in Bloomingdales in New York last year. 
Co-founders and spouses Charlotte and David Cho also recommend products with botanicals like E Nature Birch Juice Hydro Cream Sheet Mask.
"Our Birch Juice Hydro line formulas completely replace water, commonly used as the main ingredient for other skin care products, with birch sap, which is the liquid that is tapped straight from Japanese birch trees," E Nature's Anna Kim said. 
"Birch sap has been deemed the next 'coconut water' because it is full of electrolytes and antioxidants, thus providing the skin with intense hydration and soothing abilities when it is applied."
The brand SkinFood takes this even further with "food cosmetics," applying the belief that "you are what you eat," with products that contain natural food extracts rather than artificial preservatives.
Their research finds ingredients by "eating, applying and studying foods," said Jae-mo Park from SkinFood. He recommends their products with black sugar, like Black Sugar Mask Wash Off, which softens the skin.
Seoul National University's Cho says many of these Korean makeup products are beneficial because they contain sunscreen filters with high SPF, which help protect the skin from the sun's harmful rays.
But as for the effectiveness of their botanical ingredients, they are "basically all antioxidants, which have anti-inflammatory and anti-aging functions, albeit weak."
Some ingredients may be beneficial, she said. 
Black sugar can leave the skin surface more hydrated, and birch sap can reduce inflammation and retain moisture.
However, while rubber masks help with absorption, she doesn't believe a facial mask is any more beneficial than a good moisturizing cream but can be "a fun way to pamper yourself for 15 minutes."
Besides health benefits, Korean beauty products also tout eco-consciousness. E Nature uses packaging that is recyclable, and Innisfree incorporates eco-friendly ingredients, such as organic green tea and camellia flower petals, grown in Jeju Island in Korea.
As for the future of Korean beauty products, they're only going to get better, Cho said.
E-Commerce Guide by CNN Underscored: Subscribe to Beauteque Monthly for the best in Asian beauty and skin care
"As all Asians age with wrinkles and age spots, multifunctional cosmeceutical products with whitening and anti-aging properties all in one will continue to be in high demand," she said. "With continued advancement of cosmetics science and technology, new products with more innovative and functional properties will keep coming out."
Growth in the beauty and personal care industry reached a decade high last year and will continue unabated in 2019 and beyond, facilitated by new models of aspiration such as self-optimization and tailored experiences. Our latest report World Market for Beauty and Personal Care explores Euromonitor’s latest Beauty and Personal Care data to tell a story of unprecedented growth.
Global beauty and personal care recorded dynamic 6% value growth in 2018, which was the strongest for over a decade. 
Even in real terms (excluding inflation), 2018 still stands out as a strong year for the industry, reaching highs not seen since 2015, despite Western Europe’s flat performance.
The robust results largely reflect Latin America’s sustained resurgence following an economic crisis, as well as Asia Pacific’s continued strong growth. 
Asia Pacific accounted for one-third of global industry value in 2018 and is anticipated to generate over half of the total USD68 billion in absolute growth over 2018-2023.
China alone is predicted to account for USD21 billion of the industry’s growth over the forecast period – more than North America and Latin America combined. 
Sluggish consumption continues to plague the industry although volume growth did increase notably in 2018, to reach 3%. 
Volume sales declined in North America, whilst Latin America saw growth of 8%.
Premium beauty outpaced the mass segment for the fourth consecutive year in 2018. 
However, whilst premium was the standout story of 2017, 2018 was the year of the comeback for mass products. 
Mass improved on its previous performance in all regions in 2018, with the exception of Eastern Europe.
Most notably, the mass segment almost doubled its growth in North America year-on-year, with a 3% increase in 2018. 
Western Europe recorded 2% growth in mass beauty and personal care in 2018, and for the first time since 2012, premium and mass grew almost in tandem in the region – a real breakthrough for the mass segment, with the advent of a new digital era providing a breeding ground for new premium values, aspirations and products.
Skincare remains unchallenged as the largest beauty and personal care category, accounting for over one-quarter of value. 
Sales of skincare grew by 8% in 2018 helped by alignment with health and self-care, as well as being the locus of the shift to “cleaner” formulations in the industry, contributed to its strong growth in 2018.
Other categories able to align with these new consumer values also reaped rewards, including baby and child-specific products and make-up with skincare benefits. 
Recent stalwart categories of insurgent activity, notably colour cosmetics and fragrances, have lost momentum as they struggle to adapt to long-term shifts in trends.
 A cooling-off of social media and particularly the Instagram aesthetic has been of severe detriment to colour cosmetics, as this formed the basis of many brands’ core strategies.
In 2018, the percentage of beauty and personal care products sold online reached double digits for the first time, accounting for 10% of all sales and registering growth in excess of 20% year-on-year.
On a global scale, this is significant, considering that it is the first time sales online overtook sales through direct sellers such as Avon and Natura. Online is considered the closest competitor to direct sellers in the direct-to-consumer environment.
Beauty specialist retailers continue to dominate the landscape, with sales of almost USD73 billion in 2018 and a 4% CAGR over 2013-2018. 
Online sales of beauty specialists, such as Ulta, Sephora and Space NK, and brand websites are buoyant, highlighting the importance of omnichannel retailing. 
Multi-brand retailers are experiencing a revival both online and offline, as the power of the brand declines and the brand-led format of department stores and mono-brand retailers weakens. 
Multi-brand retailers can instead merchandise on function, positioning or ethos rather than brand, and this is paying dividends.
The top five companies in the key regions of Western Europe, North America and Asia-Pacific are experiencing erosion of their combined share, notably in skincare and colour cosmetics, as these categories become more fragmented.
Whilst insurgents rise quickly to disrupt the status quo, continued innovation and renovation are required to stay ahead. 
In the past few years, brands in the fickle and trend-led make-up space, such as NYX, ELF and The Est?e Edit, have experienced rapid rises and falls. 
NYX, for example, was posting triple-digit growth rates at its peak, which slowed to single digits in 2018.
WHEN LUXURY BEAUTY BRANDS COME KNOCKING AT YOUR DOOR, you know you've done something very, very right. 
Julie Cusson's journey with Chanel began in 2010 when the brand invited her to be the new national makeup artist for Chanel Canada. 
In her role, Cusson brings the brand to life using its luxe products on celebs and models, and her work and expert advice have been featured in magazines around the world. 
Here, Cusson talks to Cosmetics about the Chanel products she can't live without and one that she would like to create.
WHEN LUXURY BEAUTY BRANDS COME KNOCKING AT YOUR DOOR, you know you've done something very, very right.
 Julie Cusson's journey with Chanel began in 2010 when the brand invited her to be the new national makeup artist for Chanel Canada. 
In her role, Cusson brings the brand to life using its luxe products on celebs and models, and her work and expert advice have been featured in magazines around the world. 
Here, Cusson talks to Cosmetics about the Chanel products she can't live without and one that she would like to create.
To me, Chanel is the house - it's everything! It's the technology, the creativity and the savoir faire when it comes to creating their products. 
They're always doing research to continue to advance the technology they use to create their products; it's something I really appreciate as a makeup artist.
If you could develop a product with the brand, what would it be?
I love to wet eyeshadows when I'm working, so I would be really interested in developing an eyeshadow that is already damp to achieve the same effect.
How do Chanel products differ from other luxe brands?
The importance they place on using new technology to develop innovative products, like the new Vitalumi?re loose powder foundation. 
I love the idea of using a loose powder to create a foundation with such a light texture. They also pay a lot of attention to making sure the colours are balanced.
 It's the commitment to always finding the right shade, and the right texture, which is really important for me as a makeup artist.
There are so many! How about my top three? My first one is Le Blanc de Chanel, a white, sheer illuminator. 
You can use it as a primer, it minimizes pores, it hides dark circles - I even put it on top of foundation to illuminate the skin.
 I also like to add a little to my foundation at the end of the summer for a subtle transition. 
The second one is the Eye Shadow Base in Beige. 
When used as a lid primer it conceals veins and imperfections and keeps the eyeshadow in place, but I also use it as a concealer for blemishes and to contour the lip line. 
Finally, I'm a big fan of mascara, and the Volume de Chanel mascara is my favourite. I love the shape of the brush and how it distributes product. -Lauren Kerbel
The global vegan cosmetics market size was estimated at USD 12.9 billion in 2017.
 Surging demand for personal care products, coupled with rising awareness regarding cruelty free beauty, is expected to be one of the key trends escalating market growth.
Consumers worldwide are becoming increasingly aware about effects of their purchasing preferences and patterns on society and the environment. 
Consumers are now more conscious about choosing products and they also take a note of raw materials and source origin.
The global vegan cosmetics market size was estimated at USD 12.9 billion in 2017. Surging demand for personal care products, coupled with rising awareness regarding cruelty free beauty, is expected to be one of the key trends escalating market growth.
Consumers worldwide are becoming increasingly aware about effects of their purchasing preferences and patterns on society and the environment. 
Consumers are now more conscious about choosing products and they also take a note of raw materials and source origin.
The cosmetics industry is highly competitive in nature and requires top performing items that reach the uppermost levels of innovation and effectiveness. 
Growing environmental awareness has impelled several companies to avoid usage of animal derived raw materials by developing natural resources that are identical and overtake performances of conventional resources.
 Increasing research and development activities in the field is anticipated to help the market gain tremendous traction.
In recent times, sharp rise in the number of beauty blogs and social media accounts that are committed to benefits of going chemical-free has worked in favor of the market by enhancing consumer’s information. 
In 2016, a Democratic senator from California, Dianne Feinstein, introduced the Personal Care Products Safety Act, a bill to reinforce regulations on ingredients in personal care products.
Changing perception of consumers towards animal free products, coupled with growing popularity of environment sustainable products, is fueling the demand for naturally derived products.
 Manufacturing of naturally-derived products aid in reducing pollution and reducing dependence on petroleum based products.
 Rising demand for chemical-free skin and hair products along with changing lifestyles of consumers is estimated to stoke the growth of the market.
Growing trend of veganism, especially among younger generation, is playing a pivotal role in the development of the market. 
With more millennials embracing vegan lifestyles, it is no longer considered unconventional. 
It is now trendy, with many A-list celebrities supporting the benefits of living a vegan lifestyle and increased options available online and on high street.
According to market demand, players are launching new outlets across various geographies. 
These outlets play an important role in analysing consumer purchasing behaviour, thereby making it easier for manufacturers to design new products. 
Online stores are emerging channel of distribution, which can be convenient medium for customers to buy these product.
Major cosmetic manufacturing companies across the globe have realized the importance of making products, which use ingredients that are mineral-based or plant-based, rather than manufacturing products that are infused with animal extracted ingredients. 
Animal free products have far superior characteristics and beneficial properties such as healing aliments and soothing skin.
The hair care cosmetics industry broadly comprises of shampoos & conditioners, which are easily available, and vegan hair mousse, gel, spray, hair mask and more, which are a little difficult to find, based on regional demographics.
 Several companies such as Zuzu Luxe and Bare Blossom invest heavily in research activities and explore the market to come up with organic (animal-free) ingredients such as babassu oil, which is procured from Brazil, and Western Australia’s sandalwood extracts, which are widely preferred by consumer base across the globe.
There are several advantages of using animal-free makeup products such as fewer ingredients usage, no harmful chemicals, bypassing animal byproducts, plenty of moisture from plant extracts, and favors sensitive skin. 
Rising awareness regarding advantages of these products is poised to spur the growth of the market.
Apart from regular cosmetics available for women across the world, several major multinationals are working in line with men’s grooming products. 
The most common cosmetics used by males include face wash gels, body wash, and deodorants among others. 
Companies such as Superdrug, Bulldog and The Body Shop have an exhaustive list of men’s cosmetics, which are used on a regular basis.
There are multiple user-friendly websites such as Vegan Cuts, Pangea the Vegan Store, and Vegan Essentials that provide seamless shopping experience to consumers globally.
 E-commerce is a prominent segment in the vegan cosmetics market, with women being the primary end users. 
Ease of shopping offered and availability of promotional offers and listed deals on variety of brands are contributing to the growth of the segment.
In several regions including Europe and the U.S., governments have provided flexibility in working hours of supermarkets and hypermarkets, which indicates that they can be open till late during night. 
This provides significant growth opportunities for companies to strategically place their products in such supermarkets rather than drugstores or specialty retailers.
Departmental stores are targeted by multiple companies engaged in sales and distribution of cruelty-free cosmetics, such as L’Or?al and Unilever, as they are the one stop market spaces for a variety of consumer needs. 
In China and other emerging economies, consumers prefer going to their nearby departmental stores for convenient smooth shopping experience, simultaneously saving time.
With increasing sales across the globe, marketers of large multinationals are focusing on effective sales and distribution channels to increase their product visibility and establish a strong network of supply. 
Primary reason for the growth of specialty stores is consumer’s ease of selecting colors and compare available brands.
Across the U.S. and Germany, stores such as Bloomingdale’ and Neiman Marcus are getting significant results by placing premium vegan cosmetics along with their range of luxury clothing and accessories. 
Apart from these departmental stores, several spas such as Bella Reina are extending their services to post spa make up and body massages by using cruelty-free cosmetics, which in turn is bolstering the growth of the market.
As per a survey conducted by The Physicians Committee across North America, more than 70% of the population claims to more likely use vegan cosmetics that are not animal tested and favors development of animal-tested alternatives.
The cosmetics market in the region is registering faster growth as compared to other regions. 
According to the CEO of L’Or?al, demand for cosmetics in North America is projected to be gradually rising, especially vegan products. 
Presently, rising demand for herbal cosmetics is supplementing the growth of the region. 
Therefore, large industry players in the region are launching new products for the population in the region.
Transdermal nature of cosmetics is the new concern for consumers across Asia Pacific., which is boosting the growth of animal-free cosmetics in the region. 
Color cosmetics are being increasingly used, followed by skin care, hair care, and face care products.
China and Japan are sights of high growth rates in Asia Pacific. 
Departmental stores and supermarkets are the most preferred retail platforms in the region. 
Spiraling demand for cruelty free products such as color cosmetics, skin, sun care, and hair care products is one of the primary factors propelling the regional market.
Vegan products are strictly manufactured without any animal products and are not tested on animals.
Focus on R&D activities is paving way for novel products and use of natural harmless chemicals, which is helping market players to consolidate their positions in the arena.
Cruelty free cosmetic manufacturers are responsible for designing, manufacturing, packaging, and storing end-to-end products, catering to all requirements. 
Some of the key manufacturers in the industry are Urban Decay, Ecco Bella, Bare Blossom, Billy Jealousy, MuLondon Organic, and Modern Minerals Makeup. 
These companies are widening their operational boundaries across different countries in the world.
By analysing consumer behaviour and preferences, companies innovate and launch new products to meet customer demands.
Moreover, comfort of consumers is also addressed while designing a product and its packaging layout. 
Key players use compostable packaging and agri-based inks for their packaging. 
Cosmetic manufacturers add a larger share of value to the final product with their efforts and innovations to manufacture a product.
Whiffs of fragrant roses, jasmine and bergamot are rising from the flask.
"You smell those flowery tones? These are the basis of all women's perfume," says Guy Delforge, spraying a bottle of his own creation.
From his workshop in the citadel perched above the Belgian city of Namur, he uses ingredients from around the world to craft his signature scents.
A perfumer for 34 years, Mr Delforge, 78, notes a shift in the industry with customers pushing for natural, sustainable fragrances.
"Perfumes have existed for 5,000 years and the scents haven't changed much," he says.
"But today... customers want to know the artisan making their perfume. It reminds me of when I started selling perfume from my garage in the 1980s."
Millennials are the driving force behind the trends reshaping the sector, according to beauty industry magazine Cosmetics Business. 
It says they want more transparency and more gender-neutral scents - often based on citrus smells.
Citrus is one of the seven families of smells; with floral, chypre (oak moss with fruity notes), and amber often regarded as female scents, while foug?re (lavender/woody) woody and leather are often grouped as male scents.
"A person is born liking one specific scent family and that preference rarely changes," says Mr Delforge, whose eponymous line carries 40 eau de parfums, with each 100ml bottle costing €51.
In the heart of Namur's old city, Romain Pantoustier, "le nez" or nose in French, provides customers with transparency about the ingredients used in his perfumes.
The glass bottles of his Nez Zen range are refillable, the perfumes are gender neutral and also vegan, avoiding the musks from deer and other animal-derived produce were used in the past. 
Deer musk is specifically a secretion produced from the scent gland of the male musk deer.
An international convention covers the trade in musk but most products in the perfume industry now contain synthetic versions of the previously used animal scents. 
This is the one area where millennials definitely prefer synthetic ingredients instead of natural ones in their perfumes.
In the past other animal-derived ingredients used in perfume included ambergris from sperm whales, produced by the mammal's digestive system, and castoreum - a secretion made by beavers.
Synthetic versions of lily of the valley - one of the world's most expensive flowers - are also available. 
Such use of synthetics can also make products more cost effective, but often make use of petroleum and its by-products.
Mr Pantoustier, 40, says nature is the basis of his inspiration. 
He quizzes each customer on their favourite colours, textures, feelings and hobbies before recommending a fragrance. 
He also designs tailor-made perfumes for individual clients for €1,500.
"When a person comes in I ask them what they like. 
I use words to create a mapping in my head to guide them through my fragrances," he says, while drinking water flavoured with an edible scent. "Who am I to say what gender a scent should have?"
The Frenchman founded the Belgium-based business in August 2016 with his wife Aur?lie, after working as a scent designer for some of Europe's biggest perfumers.
"I wanted to move away from a more industrial approach to perfuming, and get back to a much more artistic and emotional approach."
Across the Atlantic, Charna Ethier also used to work for large firms in the fragrance sector, before founding the Providence Perfume Company in 2009.
"I noticed there was a demand for natural botanical smells that was being neglected," she says. "There's lots of greenwashing in the sector."
Inspired by her childhood on a farm on the US east coast, she says many modern shoppers are so used to synthetic smells in perfumes they do not know what natural options smell like.
Ms Ethier, 44, distils fruits, flowers, wood and plants in a pure alcohol spirits base to create her natural perfume line. 
Providence Perfume's website says the final products contain no synthetics, petrochemicals, fragrance oils, dyes, parabens, phthalates or chemical fragrances.
All her perfumes are also gender neutral, something she says is particularly appreciated by her younger clientele.
"Millennials don't want to wear their mom's perfume. 
They want to smell different, like leather, crushed herbs and smoke," she explains. 
"I get a lot of women saying they don't want to smell like flowers."
Gender fluid fragrances have surged in popularity in recent years: 51% of all perfume launches in 2018 were gender neutral, up from 17% in 2010, according to industry figures.
At Coty, the world's largest fragrance firm, with 77 brands including Chlo?, Hugo Boss and Gucci, trends for more gender fluid, sustainable and exclusive products are closely monitored.
"The companies who are winning are the industry leaders that have refreshed their proposition, and new brands because millennials are brand agnostics," says Laurence Lienhard, Coty's vice president of consumer marketing insights.
Ms Lienhard says Coty has also worked hard over the past five years to use less packaging and more organic ingredients.
"It's time for bigger brands to take a stand - so we are working on it more and more.".
Ms Lienhard adds that demand for gender fluid, universal scents is particularly strong in English-speaking countries. 
It released its first unisex offering, Gucci M?moire d'une Odeur, earlier in 2019. The scent is marketed in both men's and women's sections of perfume stores.
Back in Belgium, Mr Delforge peruses through the French Perfumers Society's official perfumes guide, which he calls "the bible" of perfumery.
"This book describes all the different scents, but two perfumers could choose the same ingredients and create a different smell. 
It is like different chefs making different types of mayonnaise. It's still mayonnaise but it doesn't taste the same," he explains. "Perfume is the same."
The British Beauty Council is calling for an independent body to be set up to investigate claims of bullying and unfair dismissal in the industry, which does not have a trade union. 
It comes after the BBC's Victoria Derbyshire programme uncovered cases of bullying across all levels of the industry.
"I was seeing grown women, strong women, crying at their desks. It was so toxic and harsh that people were just desperate to leave," says Sarah (not her real name), who had a senior role working for an international beauty brand.
She says her boss was a bully who spoke behind her back and told suppliers she was sharing their confidential information.
"After that, the bosses only gave me junior roles within projects and I was taken off the project I had been working on very successfully for two years," she says.
"I was ignored by HR and the board of directors. I feel so much anger - but it's not even anger, it's heartbreak."
Sarah has since left the company.
The beauty industry contributed ?14.2bn to the UK economy last year and employs one in every 60 people.
The Victoria Derbyshire programme has spoken to more than 20 people, from a company director to make-up artists in department stores, who claim to be victims of bullying, abuse and bad practice.
Many said they had suffered from anxiety, depression and even suicidal thoughts as a result.
Nearly all said the industry was facing an institutional bullying crisis but feared if they complained they would never work in it again.
It has no union, so employees can find they have no-one to put their case to or seek advice from outside their company.
Many of those the Victoria Derbyshire programme spoke to had signed non-disclosure agreements (NDAs), which are usually part of a deal where the employees are offered thousands of pounds for their silence.
But both Sarah and another woman said that despite signing, they still wanted their stories to be heard but with their identities disguised.
"Nicole", who worked as an executive for a well-known beauty company, says she was pushed out after telling her bosses she was pregnant.
'I was left out of meetings, I wasn't given information, they stopped cc'ing me in emails," she says. "Then, within 10 weeks of me coming back from maternity leave, I was told I didn't have a future in the company and that I should just leave.
"I basically believed everything they told me, I believed I was a bad person. I was diagnosed with depression, with stress and burnout. I spent time in a facility. I'm really lucky I recovered… but so many people don't."
It is not just women who are affected. Zak, who is now a freelance make-up artist, says he has been treated badly in the past.
"There were a lot of times when they were like, 'Are you sure you want him to do your make-up? He's a guy, he doesn't know how to do make-up,'" he says. "People are greedy in that sense and they want everything to themselves and they don't care who they throw under the bus.
"I went through a bit of a depression phase, I felt everyone around me was fake."
Employment lawyer Karen Jackson says she has dealt with hundreds of discrimination cases, including bullying and harassment in the cosmetics industry.
"I've dealt with similar claims against the same companies who don't seem to learn from past mistakes and who tolerate unacceptable workplace conduct," she says. 
"I don't understand why they won't address it and weed it out making life better for everyone."
But there are people in the industry trying to make a change.
Celebrity make-up artist Lan Nguyen-Grealis says she was a victim of bullying and harassment earlier in her career and uses the experience to be even kinder.
"It's all about sisterhood - a lot of the girls have freedom to come and speak to me offside whenever they need to, or if they need to let off steam it's fine," she says. 
"It's important the girls know this industry is amazing, but if you're a really nice person, you will sustain a great career. "
The British Beauty Council represents the voices, opinions and needs of the industry.
After being shown the programme's findings, chief executive Millie Kendall said: "It's heartbreaking an industry that we are trying to pull together is so at each other's throats.
"It does fall on the government because this isn't just a beauty industry-related issue, this is a nationwide issue. 
I think there needs to be some sort of ombudsmen or an industry body set up to make sure there is a safe place for people to go."
The Department for Business said in a statement: "Through the Equality Act, employees are protected against harassment in the workplace on the grounds of gender, race, disability, religion or belief, sexual orientation or age, and workers have remedies against this behaviour in the employment tribunals."
Kylie Jenner will sell the majority of her cosmetics company for $600 million (?463 million).
The 22-year-old's brand, including Kylie Cosmetics and Kylie Skin, will be controlled by beauty giant Coty.
Kylie says she is building the brand into an "international beauty powerhouse".
Forbes reported that she made $360 million in sales in 2018, making her the youngest self-made billionaire ever.
The chairman of Coty's board called Kylie a "modern-day icon, with an incredible sense of the beauty consumer".
Her online influence is so powerful that she?reduced Snapchat's stock market value by $1.3bn?(?1bn) when she tweeted that she does not use the app anymore.
The reality TV star launched her brand in 2015 with a line of lipsticks, and has since then branched out into face make-up and skincare.
Although she's the youngest, Kylie is the highest earner in the Kardashian family.
She faced backlash after being named a "self-made" billionaire, but defended herself saying that none of her money has come from inheritance.
She has more than 151 million followers on her personal Instagram account, as well as 22 million on her Kylie cosmetics account.
Coty, which owns brands like Max Factor and Hugo Boss, will have a 51% stake in the company.
It said the deal will be completed in 2020.
From festive gift sets to the coziest candles, luxe styling tools and gorgeous makeup organizers,?there's no shortage of gift possibilities for the beauty lover in your life. 
But with so many options comes the challenge of sorting through what's worth the splurge and what's just hype, an especially tough task if you're not beauty obsessive.
That's why we've rounded up the best beauty gifts you can give this season, and grouped them by what we'll call beauty personality types.
And for everyone else on your list, we've got great?gift ideas for him,?gifts for her,?gifts for kids,?gifts for gamers?and?Oprah-approved gifts, too.
That's why we've rounded up the best beauty gifts you can give this season, and grouped them by what we'll call beauty personality types.
 So whether you're looking for skin care goodies, show-stopping lipsticks or savings on cult-favorite products, we've got you covered.
This bundle from Too Faced is all things holiday, dreamy and luxurious. 
Not only are you getting?incredible value (with?savings of almost $300), you're also getting enough makeup for an entire look. 
With three different palettes and deluxe sizes of Too Faced's signature mascara, liquid lipstick and eye primer, this set is the real deal.
Have a Disney beauty fanatic in your life?
 Truly wow her with Colourpop's PR bundle of the Disney Midnight Masquerade Collection. 
This bundle features the Midnight Masquerade Palette (which you can buy individually), in addition to eight princess bundles (Rapunzel, Tiana, Aurora and more!), which include one liquid lipstick and one blush or highlighter. 
Does anyone really need that many options? 
Probably not, but?the sheer amount, combined with the grandeur of the packaging, is something that will absolutely drop jaws. 
You also have the option of purchasing?the entire collection without the packaging bells and whistles, which drops the price to $183.
One of the most buzzed-about skin care brands,?Drunk Elephant is known for its devoted cult following, gorgeous minimalist product design and, of course, stellar products.
 One product the brand is best known for is its TLC Sukari Babyfacial mask, a once-a-week mask that revives and brightens your skin, among tons of other benefits. 
The full-size product is $80, which means for just an extra $8, you're getting four minis (perfect for a test run before you make a bigger purchase) and a gorgeous peach-colored travel bag.
If you aspire to recreate Rihanna's perfect pout, her Fenty Beauty line is well loved for having some of the juiciest and most conditioning lip glosses on the market.?
This mini gloss bomb set is the perfect opportunity to test five shades?(four new ones, in addition to the brand's best selling FU$$Y shade), and it all comes in a gorgeous keepsake tin.
This beautifully packaged set of three holiday-themed candles is luxury at its finest. 
With?wintery scents like Spiced Orange & Clove and Birchwood Pine, cozying up and relaxing with a good book (or nighttime skin care routine) has just been made that much more enjoyable.
Urban Decay has achieved legendary status in the makeup community, thanks to the brand's line of incredible eyeshadow palettes that combine quality, versatility and fun.
 And the honey-scented, warm tone Naked Honey Eyeshadow Palette is no exception.?
You're not only getting the palette, but four other honey-themed products, from Urban Decay's cult-favorite setting spray to a juicy lip plumper.
There's nothing like luxurious, moisturizing skin care when the weather gets colder and drier. 
And many would argue that?when it comes to nourishing body products, there are none better than those from Sol de Janeiro, a brand known for its incredible-smelling collection of creams and fragrances. 
Pistachio, salted caramel and vanilla are just perfect. In this bundle, you get to test the brand's bestsellers for $30 less than the cost of individual products. 
There's nothing like luxurious, moisturizing skin care when the weather gets colder and drier.
 And many would argue that?when it comes to nourishing body products, there are none better than those from Sol de Janeiro, a brand known for its incredible-smelling collection of creams and fragrances.
 Pistachio, salted caramel and vanilla are just perfect. In this bundle, you get to test the brand's bestsellers for $30 less than the cost of individual products. 
There's nothing like luxurious, moisturizing skin care when the weather gets colder and drier. 
And many would argue that?when it comes to nourishing body products, there are none better than those from Sol de Janeiro, a brand known for its incredible-smelling collection of creams and fragrances. 
Pistachio, salted caramel and vanilla are just perfect.
 In this bundle, you get to test the brand's bestsellers for $30 less than the cost of individual products.
If you're looking for a?gorgeous, affordable makeup set that's perfect for someone building a beauty arsenal, look no further. This set features a collection of must-have matte and stunning shimmery eye shadows, perfect for a cohesive everyday or glam look; two super-wearable blush shades; champagne and golden highlighters; cult-favorite mascara; and a supersoft double-ended brush. 
The best part is that it's all packaged together in a sleek travel case that has a huge mirror, perfect as an at-home vanity or traveling companion.
Facial sprays are great to use first thing in the morning, as an afternoon refresher and as a relaxing part of your nighttime skin care routine. 
Basically, you can never have enough of them.?
This trio from Mario Badescu is an ultra-affordable cult favorite?that's available in a charming holiday packaging perfect for gifting, or splitting up into multiple stocking stuffers.
If you know someone looking for simple, clean and reliable skin care for the drier winter months, this set from Kiehl's includes everything someone would need to get hooked. 
From goodies like the?Midnight Recovery Concentrate?and?Calendula Herbal-Extract Toner?(two of my can't-live-without winter skin care staples),?this collection is focused on hydration and radiance. Plus, it comes in an absolutely festive holiday gift box made from recycled materials.
When it comes to brightening, there's no better place to start than this gift set from Tatcha. 
Yes, the brand's products can be pricey, but if you or someone you love has sensitivity issues, Tatcha's products are some of the most gentle, yet effective, we've tried.
?They're great for all skin types and ages, and the packaging is just as showstopping as the products.?
And the savings on this bundle is incredible.
 With the original value of the three products being $251, you're essentially getting the Violet-C Radiance Mask for free.
Peter Thomas Roth is known for luxurious skin care, and the brand's masks are no exception.?
With this six-piece gift set, you'll be saving a ton: Originally valued at over $200, the five face masks (like the?24K Gold Mask Pure Luxury Lift & Firm Mask) and the?Water Drench Hyaluronic Cloud Cream Hydrating Moisturizer?are yours for just $75.
Glow Recipe's?Watermelon + AHA Glow Sleeping Mask?took the world by storm a couple years ago, but the phenomenon is still going strong. 
And?this gift set is both a perfect, economical option and a great excuse to treat yourself to a luxurious face mask. 
The mask is originally priced at $45, and in this set, you're getting a full-size mask, in addition to the Blueberry Bounce Gentle Cleanser and Watermelon Pink Juice Oil-Free Moisturizer, for just $48. Talk about gift set savings!
K-beauty (short for Korean beauty) has absolutely made its way into the American mainstream, and one of the best, affordable Korean skin care brands you can easily shop is Tonymoly.
?Not only are the brand's products absolutely adorable, they smell delicious (yet super clean) and are an inexpensive way to invest in a little pampering.?
This set includes rose- and peach-scented skin and body goodies like face masks, a foam cleanser, hand cream and more.
For the natural beauty lover, Origins is beloved for its use of organic skin care ingredients, 100% natural essential oils and dedication as a brand to more sustainable, eco-friendly packaging.
?This skin care essentials gift set comes with seven products (enough for a whole routine),?making this the perfect gift for someone who just moved or needs to revamp an entire routine.
 You'll get full-sized versions of the brand's most popular products, from the GinZing Gel Moisturizer to the GinZing Refreshing Eye Cream, for just $45, which is a huge bargain considering the original price of the products is $92.
Sunday Riley's?Good Genes Treatment?boasts a nearly 5-star review from over 500 reviewers on?Nordstrom.com, which is the proof of the pudding when it comes to the acclaim and popularity of this lactic acid treatment.
 With this set,?you?snag the?Good Genes Treatment, in addition to four travel-size versions of the brand's other best-selling skin correcting goodies?— from brightening serum to night oil — for a savings of over $50. 
Perfect for anyone who loves testing out high-end skin care, or is looking to make the leap to buy the full-size version.
Glamglow masks are among the best (and most fun) on the market, but they're definitely not cheap. 
Instead of splurging on one type of mask,?this set lets you try six treatment masks, one sheet mask and an eye mask.
 And if you have a couple of stockings to stuff, this is also a great item to split among people, since we highly doubt anyone's going to be disappointed receiving a Glamglow mask.
Fresh is a brand?beloved for its clean and gentle skin care that's ideal for sensitive skin types. 
This set has all you need for an effective, simple skin care regimen. The Soy Face Cleanser and Rose Collection smells and feels wonderful and works incredibly well.
 So whether you opt to give this to someone in need of a new routine (or to yourself, since you're saving $30 by purchasing the set), the products and cute packaging are sure to bring a smile to someone's face.
f you really want to wow someone, Pat McGrath is a high-end brand that creates what many would call the best eye shadows on the market. 
There's a reason that even at a steep price point, people still go crazy for the quality.
?This palette is essentially holiday perfection in 10 shades, and every detail, from the super luxurious case to the intricate design on the front, make this one of the most elegant beauty gifts someone could receive.
If you're shopping for someone who prefers a subtle glow, Glossier is your spot.
?The Makeup Set from Glossier includes three of its best-selling, fan-favorite products perfect for the ultimate everyday look. 
The Lash Slick Mascara is more lengthening than volumizing, but it absolutely stays on all day (and even during workouts). 
Cloud Paint is a subtle cheek tint with incredible staying power, and it comes in six adorable, flattering shades. 
And the Boy Brow is the ultimate product for someone who wants to keep brows in check, without too much additional shaping or color.
If you're gifting a single lipstick, make sure it's one that has it all, like this holiday-edition option from Yves Saint Laurent.?
It's luxurious, glamorous and also an incredible lipstick.?
While it's always recommended to pair a darker lip with a lip liner, these have impressive lasting power on their own — on top of being some of the most comfortable lipsticks we've ever tried.
 That's not to mention the stunning star-studded casing, which is sure to take center stage on anyone's vanity.
Laneige lip products are like no others —?incredibly moisturizing, delicious-smelling and available in the cutest (yet minimalistic) packaging.
 This set of three is perfect for having different options in your purse, at work and on your vanity, or a great opportunity to indulge in scents like peach and berry while you keep your lips moisturized.
The holiday season is the perfect time to sport a glittery, glamorous look?— and this highlighting palette from Charlotte Tilbury gives you all the tools to get there.
 Well, you'll need a brush, but other than that, these three gold shades are sure to catch the flash in holiday photos, garner tons of compliments and make you feel like a glowing goddess even if it's cold and dry outside.
A favorite of Kate Middleton, this luxurious candle might be a fairly simple gift option, but it is a classic that you can't go wrong with.?
Jo Malone candles have a long-lasting (but not overpowering) scent that quickly fills a room, and this one is sure to last you a while.
If the person you're gifting has enough neutral palettes (but isn't drawn to bright, neon colors),?this palette from Urban Decay features the perfect balance of stunning, yet wearable, colors and your necessary neutrals. 
The jewel tones are perfect for gorgeous holiday looks, and there's a great mix of matte, shimmer and metallic shades.
 The palette also includes a nice, large mirror — always a winner in our book.
Stila's liquid eye shadows are easy to use and absolutely show-stopping.?One of the most popular shades -— Kitten, a glittering pinky nude color — is available in this adorable set of minis, along with Starlight, a light champagne, and Vivid Smoky Quartz, a slightly darker brown espresso shade.
 Perfect for the person who enjoys all things sparkly, this set makes for a perfect gift or stocking stuffer.
If you know someone who's still building up her makeup toolkit, Real Techniques products are our mainstay.
?Nothing we've tried since has matched the brand's combination of great price and incredible quality when it comes to basic makeup brushes and sponges.?
Plus, the brushes are available in an orange-pink shade, which makes this a fun option.
The makeup world is filled with celebrities endorsing big brands in expensive advertisements. 
But Dollar General's humble, $5-and-under cosmetics line has gone viral, thanks to social media beauty bloggers.
In the spring,?Dollar General?(DG)?debuted Believe Beauty, an exclusive, private-label line of lipsticks, eye shadows, foundations, nail polishes and skin care accessories at the chain's more than?15,500 US stores. 
Dollar General partnered with a beauty manufacturer on the brand and is giving it prime real estate at stores: It's displaying the 150-product collection in dedicated sections at the end of store aisles, making it easy for customers to find.
The aspirational brand is "an important part of our strategy," chief executive Todd Vasos said in March.
Dollar General executives say they developed the brand to bolster the company's hold on existing customers and improve its?thin profit margins. 
Dollar General also hopes to draw Millennials with the brand. Millennials probably won't post online about snacks or a new mop they bought at Dollar General, but they have showing off their new makeup online.
The line has attracted attention from personalities with large social media followings reviewing the beauty products on YouTube and Instagram.
Beauty video bloggers, or vloggers, hold a lot of sway over makeup brands. 
Vloggers have long used YouTube and Instagram to review makeup and skincare products and to give tutorials to their followers, which for some can be up in the millions.
 Experts and beginners alike tune in to learn techniques, tips and to see if new products on the market are worth buying.
Dozens of?Believe?reviews on YouTube have already racked up hundreds of thousands of page views. 
One 16-minute YouTube review from a beauty vlogger has 125,000 views. Instagram is flooded with more than 3,000 posts using "#believebeauty."
"We're seeing really good results," Dollar General CFO John Garratt said at a presentation in June. 
He pointed to "a lot of buzz on social media" about the brand. Dollar General declined to provide the brand's sales figures for this article.
All that social media attention means free advertising for Dollar General.
 It boosts the company's image with younger shoppers and is helping lift the?dollar store empire.
"People like those kind of videos because it's something different," Taylor Horn, a blogger who reviewed Believe on her YouTube channel, told CNN Business.
 Her channel has more than 750,000 followers.
"It's cool when lines like Believe Beauty launch, where it's accessible," she said.
 "I think it's more achievable and the things that your everyday consumer can afford."
Believe may help Dollar General gain market share against drug and grocery stores, said Stephanie Wissink, who covers the beauty industry at Jefferies.
The majority of Dollar General's stores are in rural communities, so offering the brand might save small-town shoppers a longer drive out to Target or Walgreens, she said.
Dollar General added its own beauty brand to an industry that is surging.
 Sales of cosmetics, which includes makeup, lipsticks, nail polish and eye shadow, have grown 31% in the United States since 2013 to more than $17 billion last year, according to Euromonitor.
But the industry is changing rapidly. 
Social media and the rise of vloggers have democratized the market, opening it to new shoppers.
"If you're a beauty enthusiast in a small community, you can access the same content to inspire you as the metropolitan fashonista," said Wissink. 
"Historically, you would have had to subscribe to a magazine or wait until a trend reached you."
Social media has also allowed small, low-priced brands to gain loyal followings online. 
Brands such as ELF cosmetics, which sells for under $10, have appealed to bargain hunters and paved the way for mainstream retailers to offer their own affordable lines.
"People know that now they can get really good makeup for cheap," said Horn. 
"There's not as much of a stigma behind it."
Dollar General is following a similar strategy to Walgreens, Target, Zara, Forever 21 and even?7-Eleven. 
These companies have all added their own in-house cosmetics lines in recent years.
"The barriers to building a brand are not as stringent as they were in the past," said Wissink from Jefferies. 
"That's why you're seeing almost every retailer launching some level of beauty."
While skincare products, such as face masks and body scrubs, play a big role in self-care routines, they've traditionally been more workhorses than show ponies for the beauty industry.
Recently, that's started to change as skincare products have surged in popularity, thanks to interest in natural and organic ingredients, as well as a thriving community on social media.
Sales of skincare products in the US?grew by 13%?in 2018, hitting $5.6 billion, while makeup sales increased just 1%, according to data from The NPD Group, a market research company.
This is "the first time in a very long time" that the skincare industry is growing faster than the makeup industry, Stephan Kanlian, head of a think tank at New York's Fashion Institute of Technology that studies the future of the beauty industry, told CNN Business.
Conservative estimates valued?the global beauty industry at over $300 billion in 2018, according to a report from Trefis, a financial research and analysis firm.
 The global skincare market was valued at nearly $135 billion in 2018, increasing nearly 60% in the past 10 years.
 And Trefis projects it to reach $180 billion — an increase of over 30% — in the next five years.
A number of factors have contributed to the growth, according to Kanlian.
Greater scrutiny by customers of product ingredients has led to demand for natural and organic skincare brands.
New products and companies are launching at a dizzying pace,?including some formed around the concept of?subscription plans for facials.
Social media has opened up new avenues for purchasing and discussing skincare routines and trends.
Women, the primary consumers in the skincare industry, are adding anti-aging products to their skincare regimens as they get older.?
Men?are increasingly showing interest in skincare products, and in turn companies are launching new lines targeted at them.
The industry has particularly benefited from the visual nature of social platforms.
Kanlian pointed to the popularity of people posting pictures of themselves in face masks on Instagram. 
"Those are very visual," he said.
 "They're great for bloggers and vloggers to do online tutorials and consumers are taking photos of themselves in their favorite skincare masks."
Summer Fridays, a brand co-founded by Instagram influencers Marianna Hewitt and Lauren Gores Ireland, launched in 2018 with just one product: a face mask. 
They spent no money on marketing, relying solely on their social media presences. 
In less than two weeks, the mask became the best-selling skin-care product on Sephora.com with thousands of positive reviews.
 It also repeatedly sold out online.
Hewitt and Gores, with nearly one million combined followers, spent years testing products for other companies and answering questions on social media. 
Over about two years, the duo developed a product using their informal focus group on social media, ultimately coming up with a clean mask packaged in a TSA-compatible size, among other attributes suggested by their followers.
"Everything we do as far as packaging, and boxes, and messaging, and photography should really be thought of on social, first and foremost," Hewitt said.
Social media has also given consumers a platform to promote the products they love and helped them become more informed, Kanlian said.
"I don't think that we've ever seen consumers, certainly in the beauty industry, at such a high level of education and sophistication," Kanlian said. 
"People are looking anywhere that they can to find a definition for natural or organic."
That need for information is partly the result of a lack of regulation in the United States. 
Whereas Australia, Japan and many European countries have restricted thousands of ingredients, the US has only banned?11 chemicals?from being used in beauty products.
 The FDA's website says US law doesn't give it "the authority to require cosmetic manufacturers to submit their safety data."
While big legacy skincare brands such as Estee Lauder and L'Oreal have slowly started offering more natural alternatives, it took them a while to meet consumer demand, according to Kanlian.
That delay, along with the desire for more product information, created an opportunity for lots of smaller natural-based companies.
In 2018, natural skincare sales totaled $1.6 billion and accounted for more than a quarter of overall skincare sales — up 23% from the year before.
Nearly?50% of American women?who use skincare reported that they were looking for natural or organic products, according to NPD.
When Gregg Renfrew founded Beautycounter, a line of ingredient-conscious products, in 2013, she faced lots of skepticism.
"No one was talking about clean beauty," she told CNN Business.
But in recent years, the business has "grown explosively." 
Now Renfrew is committed to calling attention to the lack of regulation.
"We had to take things into our own hands," Renfrew told CNN Business. 
"We've restricted 1,600 ingredients from our formulations" based on independent research the company has done and guidelines set by other countries.
The direct-to-consumer company relies on independent consultants,?everyone from doctors to stay-at-home moms and students, to spread awareness about its products. 
The consultants direct shoppers to Beautycounter's website and can earn up to 35% in commission on sales.
In 2017, Beautycounter paid?over $80 million in commissions.
Beautycounter consultants share information about ingredients and also campaign for greater regulation in the industry. 
Beautycounter has even sent select top sellers?to Washington, DC to advocate for new laws.
"We knew that we had to build a movement of consumers who were really advocating for better beauty regulations," Renfrew said.
Kanlian sees this need for greater transparency as the future of the skincare industry.
 It's something smaller brands have realized and responded to quickly, and bigger brands are slowly starting to follow suit with new products of their own.
The FDA advised consumers not to use three Claire's brand cosmetic products after tests found they contained asbestos.
The agency issued a safety alert on Claire's Eye Shadows, Compact Powder and Contour Pallette, after they tested positive for tremolite asbestos. 
The FDA also detected asbestos in a Justice product, which had already been recalled in 2017,?according to the agency.
The three Claire's products are not believed to be for sale, but consumers who have them at home should stop using them, the FDA said.
Claire's, which sells makeup,?jewelry and accessories aimed at teens, tweens and kids, said that it has removed the three cosmetic items and any talc-based products from stores. 
The company said in a statement that its products are safe and that "customer safety is paramount."
The company took issue with the FDA's tests. 
"The recent test results the FDA have shared with us show significant errors. Specifically, the FDA test reports have mischaracterized fibers in the products as asbestos, in direct contradiction to established EPA and USP criterion for classifying asbestos fibers. 
Despite our efforts to discuss these issues with the FDA, they insisted on moving forward with their release."
Claire's said it was "disappointed that the FDA has taken this step, and we will continue to work with them to demonstrate the safety of our products."
The FDA said in a statement sent to CNN on Friday that it "is confident in the scientific validity of the testing results provided by two, separate third-party labs."
"In this case, it provided significant reassurances to the FDA when results from various tests conducted at the two, different labs aligned.
The bottom line is that because of the health risks posed by asbestos, which are well-documented by other government agencies, it was the FDA's responsibility to promptly share these findings with American consumers and warn them about their potential public health threat."
Claire's released another statement on Friday, saying it had switched to talc-free manufacturing of its cosmetics last year. 
In response to the FDA's concerns about the three products, the company said it had pulled any remaining talc-based items from its stores.
"We are taking these actions out of an abundance of caution and remain confident that any products purchased at Claire's are safe. 
We look forward to working with the Food and Drug Administration to ensure the highest safety standards for all cosmetics," the company said.
The retailer operates the Claire's and Icing brands, and?filed for bankruptcy in March last year, emerging from it in October.
In 2017, Claire's took nine makeup products off the shelves following a report by?CNN affiliate WJAR-TV?that tremolite asbestos was found in the makeup.
The FDA then tested some of the products and released the results Tuesday.
"We understand how concerning this finding is for any consumer and parents whose children may have used one of these products," according to the FDA.
 It encouraged health care professionals and consumers who may have medical issues related to the Claire's products to?report it to the FDA's adverse events reporting program.
There are no laws requiring companies to test their cosmetic products for safety, and the FDA has limited authority to ensure the safety of cosmetic products.
 It can't review products before they go to market like they do for drugs.
The agency said it's working with cosmetic manufacturers to better understand how they're making sure the talc is free of asbestos. Asbestos is often found near talc, which is mined and used in many make-up products.
Asbestos becomes dangerous when particles or fibers enter the lungs or stomach. 
If swallowed or inhaled,?tremolite asbestos?can lead to lung damage and cancer, including mesothelioma, an aggressive and deadly form of cancer.
The FDA announced that it's starting a voluntary registry for cosmetic companies to list their products and ingredients, including talc.
The?departing FDA Commissioner Scott Gottlieb, and Susan Mayne, the director of the Center for Food Safety and Applied Nutrition, called for a more modernized framework for the agency to "improve consumer safety" for cosmetics, including better ways to register products, ingredients, and access to consumer complaints.
Kylie Jenner?is selling a majority stake of her popular cosmetics line for $600 million, but she's staying on as its creative leader.
The celebrity businesswoman will sell 51% of her stake in Kylie Cosmetics to?Coty Inc.?(COTY), a New York-based cosmetics company that also owns a number of international consumer beauty brands, including CoverGirl.
 The partnership will help Kylie's brand expand globally and enter new beauty categories, the two companies said in a press release Monday.
"This partnership will allow me and my team to stay focused on the creation and development of each product while building the brand into an international beauty powerhouse," Jenner said.
Jenner's team will continue to handle her creative and communication efforts, which is notable because she's one of the most-followed people on social media. 
She has?150 million followers?on Instagram and 30 million?Twitter?(TWTR)?followers.
The cosmetics brand has generated roughly $177 million in revenue over the past year, according to Coty. 
The deal is expected to close in the third quarter of 2020.
Coty said the transaction is a "key milestone" for the company. It announced a $600 million turnaround plan in June that includes layoffs and streamlining its products and brands.
 The company also announced a $3 billion write down in value of?brands it acquired in 2015?from?Procter & Gamble?(PG), which included CoverGirl and Clairol.
Coty CEO Pierre Laubies said in the release that the deal is "an exciting next step in our transformation and will leverage our core strengths around fragrances, cosmetics and skincare, allowing Kylie's brands to reach their full potential."
Coty's stock has rallied 90% this year and jumped 4% in early Monday trading. 
The deal also helps the company future proof itself as younger shoppers are increasingly buying direct-to-consumer brands,?like Glossier.
Foundation?is a liquid or powder makeup applied to the face to create an even, uniform color to the?complexion, cover flaws and, sometimes, to change the natural?skin tone. Some foundations also function as a?moisturizer,?sunscreen,?astringent?or base layer for more complex?cosmetics. Foundation applied to the body is generally referred to as "body painting" or "body makeup."
