Forever Chemicals in Feminine Hygiene Products: Expanded Findings Raise New PFAS Concerns

Per- and polyfluoroalkyl substances (PFAS) are a class of over 4,700 compounds used for a variety of purposes across many industries. They are also bioaccumulative, persistent, and toxic, with proven endocrine-disrupting effects that have been associated with reproductive issues and adverse impacts on fetal growth and development.¹

The negative consequences of PFAS for our health and environment have led to legislative changes for some uses, such as food packaging,² but there is still limited knowledge about their dermal absorption. One previous study on sunscreen estimated that 1.6% of PFAS applied to the skin is absorbed into blood plasma, while in vitro tests suggest 24% passes through full-thickness skin and epidermis over 24 hours.^3,4

Dermal PFAS absorption is an important but overlooked area, especially when considering how feminine hygiene products are worn against the skin for prolonged periods of time, and how the mucus membranes of the vagina are significantly thinner and more permeable than the outer epidermis. For example, it's been reported that the estimated exposure doses of perfluorooctanoic acid through dermal absorption from menstrual cups is 0.77 ng/kg-bw/day—more than that from normal dust ingestion.⁵

PFAS in period products: What's new?

At the ACS Fall 2023 National Meeting, Professor Graham Peaslee and colleagues presented their work on PFAS in single-use and reusable feminine hygiene products, including the packaging. Total organic fluorine is a key marker of these chemicals, and they discovered high levels in both pad wrappers and the outer layers of some washable period underwear. They hypothesized that the PFAS were being used to keep moisture out of stored single-use products and prevent leaks from reusable menstrual underwear. At the meeting, the team discussed their next steps for testing these high-fluorine samples for 40 different PFAS compounds. Now, in new work published in Environmental Science & Technology Letters, they reveal the results of tests on 59 reusable feminine hygiene products across five product categories, using particle-induced gamma-ray emission spectroscopy to measure total fluorine.⁶ They then selected a subset of 19 products with the highest intentional fluorine use, including reusable underwear and pads, for further screening.

The team's findings revealed PFAS in 100% of the products in this subset, with 6:2 and 8:2 fluorotelomer alcohols being the most abundant compounds. This is quite a concern, since washable period products are marketed as "a greener choice," contributing to far less landfill than single-use plastic-backed products. But these new findings place an important question mark over both their environmental claims and the long-term health consequences for users. We already know from studies of functional textiles such as rain coats that abrasion and washing cause loss of both PFAS-containing microfibers as well as the formation and loss of low molecular weight PFAS.^7,8

“We feel that this work is important not only because of the discovery of PFAS in an understudied segment of consumer products experiencing rapid growth, but also because it appears the use of PFAS is entirely unnecessary,” notes Prof. Peaslee in a recent press release.

Where else are PFAS found?

PFAS are found in many other personal care items, including cosmetics. In 2021, 231 cosmetic products across eight categories were screened for total fluorine.⁹ Of these, foundation, mascara, and lip products—often worn against the skin for long periods in proximity to delicate mucus membranes—had the highest proportions. As in the period products, 6:2 and 8:2 fluorotelomer compounds including alcohols, methacrylates, and phosphate esters were most commonly detected. Another source of dermal absorption recently reported on are smartwatch bands—yet another product worn against the skin for long periods, with many people sleeping and washing without removing their devices. The study, published earlier this year, revealed that 68% of watch bands tested contained total fluorine concentrations over 1%, suggesting the widespread use of fluoroelastomers in these products.¹⁰

What’s changing?

A limit of 100 ppm for total fluorine has been set by some textiles manufacturers, and legislation has been passed banning PFAS in menstrual products in several states, including Minnesota, Vermont, Maine, California, Colorado, and Rhode Island. This is a promising start, but much more information on the chemical composition of feminine hygiene products is needed to tighten regulations across the board.

References

1. Rickard, B.P. et al. Per- and Poly-fluoroalkyl Substances (PFAS) and Female Reproductive Outcomes: PFAS Elimination, Endocrine-mediated Effects, and Disease. Toxicology 2022, 465, 153031.
2. Schwartz-Narbonne, H. et al. Per- and Polyfluoroalkyl Substances in Canadian Fast Food Packaging. Environ. Sci. Technol. Lett. 2023, 10, 4, 343–349
3. Franko, J. et al. Dermal Penetration Potential of Perfluorooctanoic Acid (PFOA) in Human and Mouse Skin. Journal of Toxicology and Environmental Health - Part A: Current Issues 2012, 75 (1), 50–62.
4. Abraham, K. and Monien, B. H. Transdermal Absorption of 13C4-Perfluorooctanoic Acid (13C4-PFOA) from a Sunscreen in a Male Volunteer – What Could Be the Contribution of Cosmetics to the Internal Exposure of Perfluoroalkyl Substances (PFAS)? Environ. Int. 2022, 169, 107549.
5. Zhou, Y. et al. Per- and Polyfluoroalkyl Substances in Personal Hygiene Products: The Implications for Human Exposure and Emission to the Environment. Environ. Sci. Technol. 2023, 57, 23, 8484–8495.
6. Wicks, A. et al. Per- and Polyfluoroalkyl Substances in Reusable Feminine Hygiene Products. Environ. Sci. Technol. Lett. 2025, 12, 8, 924–929.
7. Schellenberger, S. et al. An Outdoor Aging Study to Investigate the Release of Per- And Polyfluoroalkyl Substances (PFAS) from Functional Textiles. Environ. Sci. Technol. 2022, 56, 6, 3471–3479.
8. van der Veen, I. et al. Fate of Per- and Polyfluoroalkyl Substances from Durable Water-Repellent Clothing during Use. Environ. Sci. Technol. 2022, 56, 9, 5886–5897.
9. Whitehead, H. D. et al. Fluorinated Compounds in North American Cosmetics. Environ. Sci. Technol. Lett. 2021, 8, 7, 538–544.
10. Wicks, A. et al. Presence of Perfluorohexanoic Acid in Fluoroelastomer Watch Bands. Environ. Sci. Technol. Lett. 2025, 12, 1, 25–30.