# Per- and polyfluoroalkyls used as cosmetic ingredients - Qualitative study of 765 cosmetic products

Céline Couteau, Catherine Brunet, Romane Clarke, Laurence Coiffard

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Céline Couteau, Catherine Brunet, Romane Clarke, Laurence Coiffard. Per- and polyfluoroalkyls used as cosmetic ingredients - Qualitative study of 765 cosmetic products. Food and Chemical Toxicology, 2024, 187, pp.114625. 10.1016/j.fct.2024.114625. hal-04876063

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# Per- and polyfluoroalkyls used as cosmetic ingredients - Qualitative study of 765 cosmetic products

Couteau Céline<sup>a, b</sup>, Brunet Catherine<sup>a</sup>, Clarke Romane<sup>a</sup>, Coiffard Laurence<sup>a, b, *</sup>

## ARTICLE INFO

Handling Editor: Bryan Delaney

**Keywords:**

PFAS
Cosmetic products
Make-up
PTFE
Perfluorodecalin

## ABSTRACT

Per- and polyfluoroalkyl substances (PFAS) form a vast family comprising more than 4700 synthetic compounds. Their molecules contain a terminal functional group and a hydrophobic carbon tail (alkyl group) at which the hydrogen atoms are totally (in the case of perfluorinated compounds) or partially (in the case of polyfluorinated compounds) replaced by fluorine atoms. Due to the very specific properties of their structure, they have been used in a vast range of applications over the last 70 years. These substances are considered to be of concern for the environment. Their effects on human health are still poorly understood because studies are still too rare, but the cutaneous route could be a significant pathway of penetration.

In this context, we made a qualitative study to assess the presence of PFAS in various cosmetics such as hygiene products, skin care products, make-up and perfumes.

Among the 765 products studied, we found 11 different PFAS. Polytetrafluoroethylene (PTFE) and perfluorodecalin, present in 25.9% and 22.2% of products containing it, respectively, were the most frequent.

Although the presence of this type of ingredient seems to be limited in Europe, make-up appears to be the type of product most likely to contain PFAS.

## 1. Introduction

Substances of Very High Concern (SVHCs) are chemical families or individual chemicals likely to have adverse effects on humans and/or the environment. Under REACH regulations, a substance is considered an SVHC if it is 1) carcinogenic, mutagenic, toxic for reproduction (CMR); 2) persistent in the environment or organisms, bioaccumulative and toxic (PBT); 3) very persistent and very bioaccumulative (vPvB); or 4) an endocrine disruptor.

The term SVHC includes some substances used widely or occasionally in cosmetics. Some examples are microplastics, per- and polyfluoroalkyl (PFA) molecules and ultraviolet filters (Guerranti et al., 2019; Pütz et al., 2022; Couselo-Rodríguez et al., 2022).

We focus here on per- and polyfluoroalkyl substances (PFAS). This is a vast family of more than 4700 synthetic compounds, whose molecules have a terminal functional group and a hydrophobic carbon tail (alkyl group) in which the hydrogen atoms are either totally (in the case of perfluorinated compounds) or partially (in the case of polyfluorinated compounds) replaced by fluorine atoms (Buck et al., 2011). The general formula for a PFAS is therefore: $C_nF_{2n+2}$ or, when the molecule has a

functional group, $C_nF_{2n+1}$-R. The C-F bond has high polarity and energy, particularly due to the very high electronegativity and small size of the fluorine atom, which make this bond extremely strong and stable (Rong et al., 1994). This bond strength, combined with the three pairs of non-bonding electrons around each fluorine atom and the effective shielding of the carbon atom by the fluorine atoms, makes these molecules relatively stable. These specific chemical properties make PFAS interesting for the products in which they are used. They are non-flammable and resistant to acids and microorganisms. When a PFAS molecule contains a carboxylic acid, sulfonic acid or phosphate functional group, it is amphiphilic and has surfactant properties (Ding and Peijnenburg, 2013; Wang et al., 2021).

Per- and polyfluoroalkyl substances are man-made and have been available for over 70 years. In the 1940s, in the United States, polytetrafluoroethylene (or PTFE) was the first fluoropolymer to be synthesised and was patented by the DuPont de Nemours company under the name Teflon®. Around 900 tonnes were produced per year from 1948. Then, from the 1950s onwards, the synthesis of perfluorooctanesulfonic acid (PFOS) and perfluorooctanoic acid (PFOA) made it possible to create protective coatings with non-stick, stain-

<footnote><sup>a</sup> Faculté de Pharmacie, Nantes Université, 9 Rue Bias, 44000, Nantes, France</footnote>

<footnote><sup>b</sup> Université de Brest, LIEN, EA 4685, Brest, France</footnote>

<footnote>* Corresponding author. Faculté de Pharmacie, Nantes Université, 9 rue Bias, 44000, Nantes, France.</footnote>

<footnote>E-mail address: laurence.coiffard@univ-nantes.fr (C. Laurence).</footnote>
resistant and waterproof properties. These have been used in a wide variety of everyday products such as food packaging and kitchen utensils (non-stick properties), clothing and household/vehicle fabrics (stain and water repellent properties) (Becmeur et al., 1990; Panieri et al., 2022; Ragnarsdóttir et al., 2022).

The uses of PFAS are therefore wide-ranging. These substances are, however, fairly poorly understood, which complicates the characterization of their exposome. What is certain is that human exposure to PFAS is significant and contamination of drinking water and foodstuffs has been documented. They have also been detected in the blood serum of the population as a whole (Glügea et al., 2020). Considering these findings, we wanted to quantitatively assess the presence of PFAS in various cosmetics, such as hygiene products, skin care products, make-up and perfumes, which bring them into direct contact with the human skin.

## 2. Methods

We made a qualitative analysis of the formulas of 765 cosmetic products (hygiene products, skin care products, make-up, sun protection and perfumes; Table 1) available in supermarkets, pharmacies/drug stores and perfumeries/beauty salons. For each product, the number of PFAS and nature of the molecule(s) were determined based on the ingredients list given on the product packaging. These lists are preceded by the word ‘ingredients’ and include all the ingredients used in the particular cosmetic product, given in descending order of weight and designated by their INCI name according to the Regulation (EC) No 1223/2009. Using the European Commission database for information on cosmetic substances and ingredients, we identified about 170 chemical structures containing at least - CF₂- or -CF₃ among the ingredients in cosmetics on the European market. These structures were used to identify PFAS-containing ingredients in the products studied.

In addition to recording the presence of PFAS, we also assessed the use of synthetic fluorophlogopite, another fluorinated organic derivative ingredient.

## 3. Results and discussion

The hygiene products studied all had formulas free of PFAS. This was

<table><caption>**Table 1**
Categories and sub-categories of cosmetic products studied.</caption><thead><tr><th>Product category</th><th>Sub-category</th><th>Number of products concerned</th></tr></thead><tbody><tr><td rowspan="4">Hygiene</td><td>Shampoos/conditioners</td><td>144</td></tr><tr><td>Shower gels</td><td>24</td></tr><tr><td>Deodorants/Antiperspirants</td><td>24</td></tr><tr><td>Toothpastes</td><td>16</td></tr><tr><td rowspan="10">Personal care</td><td>Moisturisers</td><td>10</td></tr><tr><td>Anti-redness creams</td><td>19</td></tr><tr><td>Anti-blemish creams</td><td>22</td></tr><tr><td>Anti-wrinkle/Anti-ageing creams</td><td>31</td></tr><tr><td>Creams for oily skin</td><td>20</td></tr><tr><td>Hand creams</td><td>30</td></tr><tr><td>Slimming cream</td><td>21</td></tr><tr><td>Face masks</td><td>24</td></tr><tr><td>Lip balms</td><td>22</td></tr><tr><td rowspan="5">Make-up</td><td>Foundations/tinted creams</td><td>33</td></tr><tr><td>BB CC DD creams</td><td>36</td></tr><tr><td>Eye make-up</td><td>57</td></tr><tr><td>Lipsticks</td><td>51</td></tr><tr><td>Nail Polishes</td><td>32</td></tr><tr><td>Face powders</td><td>40</td></tr><tr><td>Photoprotection</td><td>Sunscreens</td><td>55</td></tr><tr><td>Perfumes</td><td></td><td>54</td></tr></tbody></table>

also the case for the sun-protection creams and perfumes studied. The presence of PFAS in skin care products is extremely rare, as we only found them in one product for oily skin, one anti-redness product, two moisturising products, two anti-wrinkle products and three facial masks. However, 18 make-up products, or 7.2% of the products in this class, contained at least one PFAS in their formulas (Fig. 1), compared with an overall 3.5% presence over all the products examined.

Of the thousands of substances belonging to the PFA family, only 11 were identified in the products studied (Table 2). In most cases, the products concerned contained only one PFAS. There could sometimes be several, however, and in the extreme case of a product intended for oily skin, there were six different PFAS (Fig. 2). Polytetrafluoroethylene (PTFE) and perfluorodecalin, present in 25.9% and 22.2% of products, respectively, were the PFAS found most frequently.

Synthetic fluorophlogopite is used more than PFAS in the products studied. We found it to be present in 60 products (7.8%), mainly those in the make-up category (Fig. 3). The presence of PFAS does not exclude the presence of synthetic fluorophlogopite, and in a number of products they are found together.

The presence of PFAS in all manner of everyday products is a major issue, given the toxicity of some of these compounds. In this context, the European Chemicals Agency (ECHA) announced at the beginning of the year that it had received a proposal for restrictions on per- and polyfluoroalkyl substances from five national authorities (Denmark, Germany, the Netherlands, Norway and Sweden). These five countries have been working together on a proposal to ban PFAS in Europe since 2019. In a statement, the Dutch National Institute for Public Health and the Environment (RIVM) said that the proposed restriction “*aims to ban both the use and production of PFAS in order to reduce the risks these substances pose to humans and the environment*”. ECHA’s Scientific Committees for Risk Assessment (RAC) and Socio-Economic Analysis (SEAC) will have the task of verifying that the proposed restriction meets the legal requirements of the REACH regulation. If this is the case, the committees will begin their scientific evaluation of the proposal. Reports from the RAC and SEAC are normally available within 12 months. Once these have been approved, they will be sent to the European Commission, which, together with the EU Member States, will then decide on possible restrictions.

Along the same lines, in France, the Ministry of Ecological Transition and Territorial Cohesion launched a 2023–2027 action plan on 17 January, with the stated aim to “*strengthen the protection of French people and the environment against the risks associated with PFAS*”.

Human exposure to per- and polyfluoroalkyl substances (PFAS) has, until now, been mainly attributed to contaminated food and drinking water (Pütz et al., 2022). Yet, as we have seen, PFAS can be used as ingredients in cosmetics, where their hydrophobicity and film-forming ability enhance product quality over time. They are also reputed to improve skin texture but are known for transdermal penetration. In hair

<figure><img src="image_4.png" /><figcaption>**Fig. 1.** PFAS identified in make-up products studied.</figcaption></figure>
<table><caption>**Table 2**
Different PFAs found in the formulas of the cosmetic products studied.</caption><thead><tr><th>PFAs identified</th><th>Formulas</th><th>Function</th><th>Number of products concerned</th></tr></thead><tbody><tr><td>Methyl Perfluoroisobutyl Ether</td><td>C<sub>5</sub>H<sub>3</sub>F<sub>9</sub></td><td>Solvent<br>Viscosity<br>agent</td><td>1</td></tr><tr><td>Methyl Perfluorobutyl Ether</td><td>C<sub>3</sub>H<sub>3</sub>F<sub>9</sub>O</td><td>Solvent<br>Viscosity<br>agent</td><td>1</td></tr><tr><td>Pentafluoropropane</td><td>C<sub>3</sub>H<sub>3</sub>F<sub>5</sub></td><td>Solvent<br>Propellent</td><td>1</td></tr><tr><td>Perfluorodecalin</td><td>C<sub>10</sub>F<sub>18</sub></td><td>Skin<br>conditioner<br>Solvent</td><td>6</td></tr><tr><td>Perfluorodimethylcyclohexane</td><td>C<sub>8</sub>F<sub>16</sub></td><td>Solvent</td><td>2</td></tr><tr><td>Perfluorononyl dimethicone</td><td>C<sub>39</sub>H<sub>71</sub>F<sub>19</sub>O<sub>4</sub>Si<sub>5</sub></td><td>Skin<br>conditioner</td><td>3</td></tr><tr><td>Perfluorononylethyl carboxydecyl<br>lauryl dimethicone</td><td>—</td><td>Skin<br>conditioner</td><td>1</td></tr><tr><td>Perfluorooctyl Triethoxysilane</td><td>C<sub>14</sub>H<sub>19</sub>F<sub>13</sub>O<sub>3</sub>Si</td><td>Non-stick</td><td>2</td></tr><tr><td>Perfluorohexane</td><td>C<sub>6</sub>F<sub>14</sub></td><td>Solvent</td><td>4</td></tr><tr><td>Perfluoroperhydrophenanthrene</td><td>C<sub>14</sub>F<sub>24</sub></td><td>Solvent<br>Skin<br>conditioner</td><td>1</td></tr><tr><td>PTFE</td><td>(C<sub>2</sub>F<sub>4</sub>)<sub>n</sub></td><td>Bulking<br>agent</td><td>7</td></tr></tbody></table>

<figure><img src="image_5.png" /><figcaption>**Fig. 2.** PFAs identified in products studied.</figcaption></figure>

<figure><img src="image_6.png" /><figcaption>**Fig. 3.** Synthetic fluorophlogopite identified in products studied.</figcaption></figure>

care products, they can improve hair brushability after shampooing. However, we did not find any cases of this use, as none of our studied shampoos or conditioners contained these substances. In the case of make-up, PFAS are incorporated to obtain a water-resistant effect.¹⁰ Currently, there are still very few studies on the presence of PFAS in cosmetics. The twelve fluorinated molecules that we identified in the formulas are all found in the European inventory, except for perfluorooctyl triethoxysilane. These compounds are not subject to any specific regulations in the European Union. As a result, they can be used on the skin, skin appendages (hair, nails) and external mucous membranes without dose restrictions.

It should be underlined that studies of PFAS exposure via cosmetics are currently very rare. Some have been carried out on a small sample of products, such as the study by Pütz et al., which was done on 45 cosmetic products only. To assess the potential risk to human health and the environment, North American researchers set out to measure total fluorine in a number of cosmetic products available in the United States and Canada, i.e. 231 products. Of the eight categories tested, foundations, mascaras and lipsticks had the highest proportion of products containing high levels of total fluorine. Twenty-nine products, including 20 with high concentrations of total fluorine, were analysed by LC-MS/MS and GC-MS. PFAS concentrations ranged from 22 to 10,500 ng/g product, with a mean and median of 264 and 1050 ng/g product, respectively (Whitehead et al., 2021). Our results show that the number of products formulated with one or more PFAS is lower than in this previous study, which suggests that formulation practices differ between North America and Europe.

In our case, PTFE and perfluorodecalin were the PFAS found most frequently in the products studied. Regarding polytetrafluoroethylene or PTFE, known under the registered trademark Teflon®, this product was originally intended for use in the manufacture of non-stick cookware, particularly frying pans. It is important to remember that it is synthesised from another fluorinated compound, perfluorooctanoic acid (PFOA), which can persist as an impurity in the final ingredient (van der Putte et al., 2010). For this reason, the United States Environmental Protection Agency (EPA) launched a program to reduce the residues of this acid in consumer products. Although research suggests that most PFOA exposure results from its use in food-contact packaging items, indirect exposure from consumer products is also likely (Trudel et al., 2008). The concentration of PFOA in materials in contact with food can reach 300 ppb, e.g. in popcorn bags, but no available study has yet assessed the PFOA contamination of cosmetics containing PTFE. It is essential to investigate this, as we know that occupational exposure to PFOA concerns not only the respiratory route but also cutaneous and digestive routes (Franko et al., 2012). It is difficult to draw conclusions on the cutaneous absorption of this molecule as the results of old studies differ so widely. According to one of these, just 0.05% of 30 mg of the ammonium salt of PFOA/cm² was absorbed in 48 h when applied in aqueous solution to isolated human epidermis, but nearly 69% of the dose of PFOA (0.5 mg of PFOA in 50 µl of acetone) was absorbed in 24 h after application to a human skin explant (The Hazardous Substances Data Bank (HSDB)). Data on the distribution of PFOA in the human body is also scarce, although it appears to be mainly in the liver, lungs and kidneys. Over 90% of PFOA is bound to serum albumin and is not metabolised. The serum half-life of PFOA is long, being around 4 years. It is also likely to cross the placental barrier and accumulate in the foetus. Furthermore, it passes into breast milk. Renal elimination is negligible in humans. In the general population, the 95 percentile of serum PFOA concentrations in adults measured in the USA was 7.7 µg/L (both sexes combined); in Germany, a higher value of 10 µg/L was found (Fasano et al., 2005; EFSA, 2008). In populations exposed during their professional activities, much higher serum concentrations of PFOA (of the order of mg/L) were found (Olsen et al., 2003; Schulz et al., 2011; NHANES Fourth National Report on Human Exposure, 2013). Based on several studies, a link seems to have been established between PFOA exposure and elevated cholesterol levels (Steenland et al., 2010). Data
currently available suggest causality in pathologies such as kidney or
testicular cancer or even disruptive effects on reproduction, although
these have yet to be confirmed (Temkin et al., 2020; Bartell and Vieira,
2021; Coperchini et al., 2021; Steenland et al., 2022).

Even less data is available on perfluorodecalin than on PTFE. The little information available concerns its use in patch form in laser tattoo-removal, where it is used to optimise the procedure (Reddy et al., 2013; Danysz et al., 2020; Moustafa et al., 2020), or in emulsions dosed at 2% offered as alternatives to hyperbaric oxygen therapy to accelerate healing (Gold and Nestor, 2020). Perfluorodecalin, as an oxygen carrier, is thought to improve the skin's barrier function (Stanzl et al., 1996). A footbath procedure was even proposed to treat ischaemic ulcers around thirty years ago (Iwai et al., 1989). It should be noted that no percutaneous absorption of this substance is known.

Based on analysis of samples taken from Holstein cows and heifers exposed for life to per- and polyfluoroalkyl substances through consumption of contaminated feed and water, it was concluded that PFAS with more than four carbons were capable of accumulating in plasma and skin (Lupton et al., 2022). This is precisely the case for all the molecules we were able to identify, with the sole exception of pentafluoropropane. Because of its volatility and its use as a propellant, the latter has already been studied more from for toxicity by inhalation. Its toxic potential appears to be low. However, one of its minor metabolites, 3,3,3-trifluoropropanoic acid, has been shown to be highly toxic in rats (Bayer et al., 2002).

For a qualitative study, it is not possible to rely on the total fluorine dosage because our study shows that, particularly in make-up products, another fluorinated raw material can be used that does not belong to the PFAS family, namely synthetic fluorophogopite or ‘synthetic mica’ (Fig. 3). Although this substance is considered safe to use according to the current state of knowledge (Becker et al., 2010), available information remains extremely limited for the moment. In the formulas studied, we were able to estimate that PFAS are present in concentrations ranging from 0.25 to 5.00% (m/m) depending on the molecules considered and the applications.

We conclude that, as studies on PFAS and their potential precursors present in various consumer products and clothing show these to be substances of concern for the environment and, furthermore, other studies suggest that the cutaneous route is a potentially important route of human exposure (Fujii et al., 2013; Schultes et al., 2018; van der Veen et al., 2020; Weatherly et al., 2021), it is now vital to examine human exposure taking place via cosmetic products.

CRediT authorship contribution statement

**Couteau Céline:** Writing – original draft, Validation, Project administration, Conceptualization. **Brunet Catherine:** Data curation. **Clarke Romane:** Data curation. **Coiffard Laurence:** Writing – review & editing, Writing – original draft, Validation, Supervision, Formal analysis, Conceptualization.

Declaration of competing interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Data availability

Data will be made available on request.

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