Toxic PFAS Found in Reusable Menstrual Products
PFAS chemicals were found in all reusable menstrual products tested, with signs of intentional use in one-third.
Reusable menstrual products are marketed as an eco-friendly alternative; however, new research suggests they may come with hidden chemical risks.
A new peer-reviewed study from Indiana University and the University of Notre Dame, published in Environmental Science & Technology Letters, found toxic “forever chemicals” in a wide range of reusable menstrual and incontinence products.
The researchers detected per- and polyfluoroalkyl substances (PFAS) in every product they tested and found signs of intentional use in around one-third of period underwear.
PFAS exposure risks in menstrual products raise safety concerns
PFAS are synthetic chemicals used to make materials resistant to water, oil and stains. They are in a huge number of everyday items, such as nonstick pans, waterproof jackets, fast-food wrappers, dental floss and mascara. As well as being persistent in the environment, these chemicals are also in our bodies.
Studies have linked PFAS exposure to cancer, hormonal disruption, immune suppression and developmental effects in children.
One place people might not expect to find PFAS is in menstrual products.
“Feminine hygiene products stay in contact with the skin for extended periods of time, and the risks from the dermal absorption of PFAS are not well understood,” said senior author Dr. Marta Venier, an associate professor at Indiana University.
Until recently, most data focused on single-use pads and tampons. In 2020, independent testing revealed high fluorine levels in Thinx period underwear, leading to a class-action lawsuit. The company settled for $5 million in 2023 but did not admit wrongdoing.
Meanwhile, consumer demand for reusable products such as period underwear, menstrual cups and reusable pads is growing fast. When these products are laundered or disposed of, PFAS can leach into water systems and persist in soil, contributing to wider environmental contamination.
“The reusable menstrual product market is a rapidly growing market, which relies heavily on the idea that these products are environmentally conscious because of the significant reduction in the use of paper and plastic products,” said senior author Dr. Graham Peaslee, a professor in the Department of Physics and Astronomy at the University of Notre Dame.
There’s also no legal requirement for brands to disclose PFAS use, which leaves consumers guessing – and possibly at risk.
“Since reusable products are on the rise, it’s important to ensure that these products are safe. This is crucial, especially for adolescents and young women, who are more vulnerable to potential negative health effects,” said Venier.
Scientists test reusable menstrual products for PFAS
The team tested 59 new reusable menstrual and incontinence products from across North America, South America, Europe and Asia-Pacific. These included period underwear, reusable pads, menstrual cups and reusable incontinence wear. They used a method called particle-induced gamma-ray emission (PIGE) spectroscopy to screen each layer of every product (323 layers in total) for total fluorine, a marker of PFAS. They then selected 19 of those products for more detailed chemical analysis using mass spectrometry to test for 42 specific PFAS compounds.
Over 70% of the products tested had low fluorine levels, suggesting no intentional PFAS use; however, a significant number did not.
Around one-third of period underwear and one-quarter of reusable pads had fluorine concentrations above 110 parts per million (ppm), which likely suggests intentional addition. Some samples, including period underwear, had levels over 1000 ppm, which is in the range of polymeric PFAS used in waterproof coatings.
The deeper analysis confirmed the presence of PFAS in every single product tested. Concentrations ranged from 21 to 2200 nanograms per gram (ng/g) of material, with a median of 380 ng/g. The majority of the chemicals found were neutral PFAS, including fluorotelomer alcohols (FTOHs) and fluorotelomer methacrylates. One compound, 8:2 FTOH, was common in North American products and is known to break down into PFOA, a well-studied toxic PFAS.
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Neutral PFAS
Neutral PFAS are a type of PFAS that carry no electrical charge, which may make them more likely to pass through skin compared to charged (ionic) PFAS.
“8:2 FTOH can be transformed into more toxic PFOA once inside the body,” said co-author Sydney Brady, a PhD student in Venier's lab.
PFAS appeared in products from every market, though the chemical mix varied. The fluorinated compounds were usually present in just one layer of the product.
At least one PFAS-free product was identified in each category tested.
“Only a subset of the products had high levels of PFAS present, which means that PFAS must not be essential in the manufacture of reusable feminine hygiene products,” said lead author Dr. Alyssa Wicks, a postdoctoral researcher at Duke University.
“This is good news in that it demonstrates PFAS are not required to produce these environmentally conscious products, and manufacturers should be able to make these textile products without chemicals of concern in them,” she added.
Study highlights need for PFAS regulation and labelling
PFAS can migrate from textiles onto skin, and dermal absorption is thought to be a likely route of exposure, especially for neutral PFAS, with products such as period underwear worn for hours at a time – that’s a concern.
“We found that almost a third of them were being made with PFAS,” said Peaslee. “This means these products are both a risk to the wearer as well as to the rest of us when they are eventually disposed of.”
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Why use PFAS at all? It may be to improve leak protection or stain resistance; however, since many products manage without them, manufacturers do have other options.
Right now, consumers have no way of knowing what’s in the products they buy. There’s no labelling requirement for PFAS, although some US states are starting to legislate.
“Increased transparency from manufacturers would help consumers make informed decisions about what they’re purchasing for themselves and their families,” said Venier.
“There’s still a lot we don’t know about the extent to which PFAS are being used in the manufacturing of these products, and too much we don’t know about the potential for these chemicals to be absorbed through the skin by the consumers who wear them,” said Peaslee.
“While we do know that these chemicals have been linked to serious environmental and human health issues, we do not yet know what fraction of these PFAS make it into humans by direct exposure and indirect exposure at the end of life of these products,” he added.
“This paper and others like it will help regulators and manufacturers alike to identify product markets where PFAS are being used and to find better alternatives moving forward,” Peaslee concluded.
Reference: Wicks A, Brady S, Whitehead HD, et al. Per- and polyfluoroalkyl substances in reusable feminine hygiene products. Environ Sci Technol Lett. 2025. doi: 10.1021/acs.estlett.5c00553
This article is a rework of a press release issued by Indiana University. Material has been edited for length and content.
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