In 2020, the Sierra Club and consumer watchdog group Mamavation began commissioning lab tests on feminine hygiene products. What they found prompted lawsuits, regulatory attention, and a serious conversation about whether the products women press against the most absorptive tissue in their bodies are as safe as the marketing implies.
The short version: many of them aren't.
Per- and polyfluoroalkyl substances, known as PFAS or "forever chemicals," have been detected in tampons, pads, period underwear, and incontinence products at concentrations that exceed regulatory thresholds for drinking water by orders of magnitude. The chemicals are linked by the U.S. Environmental Protection Agency to fertility problems, hormone disruption, immune system effects, certain cancers, and developmental issues in children. They persist in the body for years and in the environment essentially forever.
And often, they're showing up in products specifically marketed as "organic," "natural," "non-toxic," or "sustainable."
This is a brand journalism piece rather than a clinical one. The science here is real, the regulatory environment is shifting, and women deserve information clear enough to make actual decisions with. Here's what the research shows, what the lawsuits established, and what to look for when you're choosing period products.
What Are PFAS?
PFAS are a family of roughly 12,000 manufactured chemicals first developed in the 1940s. Their structural property (a chain of carbon-fluorine bonds, the strongest bonds in organic chemistry) makes them extraordinarily durable. They're used to make non-stick cookware non-stick, raincoats waterproof, food packaging grease-resistant, firefighting foam effective, and many other applications where you want something to repel water or grease.
This durability is also the problem. PFAS don't break down. The half-life of common PFAS in the human body ranges from 3.5 to 8 years (PFOS, one of the most-studied, has a 4.8-year half-life). In the environment, they persist for centuries. Hence the colloquial term "forever chemicals."
PFAS are now detectable in essentially everyone tested. They're in our drinking water, our food, our soil, our blood, and according to recent studies, in placental tissue and breast milk. They reach babies through cord blood and through breastfeeding. The exposure is universal, which is why even small amounts in routinely-used products like period care matter cumulatively.
What PFAS Are Linked To
- The U.S. Environmental Protection Agency has compiled the health effects research, which includes:
- Decreased fertility and increased risk of infertility.
- High blood pressure during pregnancy.
- Increased risk of certain cancers including kidney and testicular.
- Developmental delays and low birthweight in children.
- Hormonal disruption, including thyroid effects.
- Elevated cholesterol levels.
- Reduced immune system function, including reduced effectiveness of vaccines.
- Liver damage with chronic exposure.
Some of these effects are dose-dependent. Some happen at exposures well below what most people would consider concerning. The EPA's 2022 revised drinking water health advisory set the safe threshold for PFOA at 0.004 parts per trillion and for PFOS at 0.02 parts per trillion. These are vanishingly small concentrations, set this low because the cumulative effect of lifetime exposure compounds.
What Was Found in Period Products
The Mamavation and Environmental Health News investigations between 2020 and 2022 commissioned independent lab analysis of consumer feminine hygiene products. The methodology used organic fluorine testing, a screen for the presence of PFAS that's standard in environmental and consumer product research. Detection of organic fluorine indicates PFAS presence (organic fluorine is essentially only present in human-made fluorinated compounds, of which PFAS are the dominant category).
Findings across the studies:
- 48% of sanitary pads, incontinence pads, and panty liners tested positive for organic fluorine indicating PFAS presence.
- 22% of tampons tested positive.
- 65% of period underwear tested positive.
Concentrations in some sanitary products ranged from 11 to 154 parts per million, dramatically higher than what the EPA permits in drinking water and at levels that researchers consider consistent with intentional addition rather than incidental contamination.
Significantly, products marketed as "organic," "natural," "non-toxic," "sustainable," or "no harmful chemicals" tested positive for PFAS at high rates. In one Mamavation analysis, 13 of 22 products that tested positive carried these "clean" marketing claims. In another, 13 of 18 such products contained PFAS.
This is the part that matters for women trying to make informed decisions. Choosing "organic" tampons or "sustainable" period underwear does not, based on this data, reliably mean choosing PFAS-free products.
Why Vaginal Tissue Matters Specifically
PFAS are most dangerous when ingested (which is why drinking water regulation is the primary focus). But they also enter the body through dermal absorption, and the dermal absorption rate varies by tissue type.
The vaginal and vulvar tissue is highly vascularized (rich in blood vessels) and lacks the keratinized barrier that protects skin elsewhere on the body. Compounds that pass slowly through forearm skin can pass much more rapidly through vaginal tissue. This is why vaginal medications work at lower doses than oral or skin-applied medications, and it's the same reason why PFAS in products that contact vaginal tissue is potentially more concerning than the same chemicals in products that contact less absorptive skin.
Researchers including Erin Bell at SUNY Albany and Graham Peaslee at the University of Notre Dame have specifically flagged the vaginal route as a transdermal exposure pathway worth studying further, given how much PFAS contact this tissue receives across decades of menstruating life.
What's Already Happened in the Lawsuits
From 2020 to 2022, three class action lawsuits against Thinx, the period underwear company, alleged PFAS contamination in their products. The suits were filed in California, Massachusetts, and New York and consolidated in the Southern District of New York in 2022.
In December 2022, Thinx reached a settlement that offered women who purchased Thinx products the option to submit for a refund or future-purchase voucher. The non-monetary terms required Thinx to ensure PFAS are not intentionally added at any production stage and to require their suppliers to attest to similar preventive measures through a code of conduct.
Thinx denied that PFAS had been intentionally included in its products and argued that none of the plaintiffs had suffered injury. The settlement was negotiated without admission of fault, which is standard for class action resolutions.
The legal action established something important: even brands that strongly market themselves as clean and sustainable can have PFAS contamination, and the regulatory environment is starting to require disclosure and prevention rather than allowing the industry to police itself.
How PFAS End Up in Products in the First Place
According to researchers studying contamination patterns, there are two distinct scenarios.
Inadvertent contamination. When PFAS concentrations in a product are in the low parts per million or lower, the manufacturer often genuinely doesn't know the chemicals are present. PFAS migrate from raw materials sourced from suppliers, machinery used in manufacturing, packaging materials, or environmental contamination at production facilities. The final manufacturer didn't add them deliberately and may not be testing for them.
Intentional inclusion. When concentrations are in the hundreds or thousands of parts per million, that's typically inconsistent with incidental contamination. PFAS at high concentrations in a product usually means the manufacturer added them for a functional purpose: stain resistance in period underwear, absorbency enhancement in pads, leak-resistance in liners, or surface treatments that affect how materials handle moisture.
Both scenarios are problematic but in different ways. Inadvertent contamination requires supply chain testing and prevention. Intentional inclusion requires either replacement of the function with safer chemistry or regulatory action to prevent it.
What Regulation Is Actually Doing
The federal regulatory response has been slow, partial, and limited.
In 2002, manufacturers under EPA pressure agreed to phase out PFOS, one of the original PFAS. In 2015, manufacturers similarly agreed to phase out PFOA. Both phase-outs apply only to the specific compounds named, and the chemicals were largely replaced with newer PFAS variants (GenX, PFBS, PFHxA, others) that have similar properties and similar concerns. Different generation, same family.
In 2021, the EPA announced a "strategic roadmap" to restrict PFAS use and hold polluters accountable. The 2021-2024 timeline was unrealistic for a 12,000-chemical family used across the entire industrial economy, and cleanup will continue for decades.
Also in 2021, President Biden signed an executive order including a "buy clean" provision that would phase out federal government purchases of PFAS-containing products by 2050. This affects what the government buys but doesn't directly regulate consumer products.
At the state level, action has been faster. New York passed legislation in 2019 requiring period product manufacturers to list deliberately-added substances. California followed in 2020. These laws require disclosure but don't ban PFAS or set safety thresholds.
For consumers, the practical reality is that federal regulation is not currently protecting you from PFAS in period products. State-level disclosure helps, but only for products manufactured for sale in those states and only for ingredients deliberately included.
What to Look For When Choosing Period Products
The clearest takeaway from the research is that marketing claims alone are not sufficient. "Organic," "natural," "non-toxic," and "sustainable" don't reliably mean PFAS-free. Brands that genuinely don't include PFAS need to demonstrate it specifically.
Signals That a Brand Takes This Seriously
Third-party testing for organic fluorine or PFAS. Brands that have tested their products and published results are demonstrating that they care enough to verify rather than assume. Look for specific testing references, not vague "no toxic chemicals" claims.
OEKO-TEX certification. This international standard tests for harmful substances in textile products, including PFAS. Certified products have been independently verified.
Made Safe certification. A consumer-facing certification that screens for PFAS and other concerning chemicals.
Specific ingredient lists. Brands that list every component of their products are demonstrating transparency. Brands that hide behind "proprietary blends" or vague descriptions are not.
Direct response to PFAS testing. When Mamavation, Sierra Club, and other watchdog groups have tested products, brands that commit to addressing findings (not just deny them) demonstrate ongoing accountability.
Specific Period Product Categories
For tampons and pads, look for 100% organic cotton products with explicit no-PFAS testing or OEKO-TEX certification. Brands like Natracare, August, Cora, and Lola have made specific PFAS-free commitments at various points, though product formulations change and verification through current testing is recommended.
For period underwear, the category most affected by PFAS in early testing, look for brands that have publicly committed to PFAS-free production and published testing results. Saalt, Aisle, and Knix are among the brands that have made specific commitments in this category.
For menstrual cups and discs, silicone-based products generally don't contain PFAS in the silicone itself, though packaging and surface treatments can be a separate consideration. Medical-grade silicone from established manufacturers is among the safer options for women looking to minimize PFAS exposure.
For period care during heavy bleeding or postpartum, products specifically marketed for these uses (pads, large pads, postpartum mesh underwear) have been less consistently tested for PFAS. Choose certified-organic products and contact manufacturers directly if you can't find testing data.
Why This Matters Beyond Period Products
PFAS are everywhere. Period products are one of many consumer categories where contamination has been documented. Cosmetics, food packaging, dental floss, contact lenses, certain clothing, certain personal care products, and many other categories have similar issues.
The case for paying particular attention to period products is the combination of vaginal tissue absorption, the multi-decade exposure window across reproductive life (12 to 50 years for many women), and the fact that the products are pressed against the body for hours at a time, often daily. Cumulatively, this is a meaningful exposure pathway that women have not generally been informed about.
This isn't a call for panic. It's a call for informed decisions. PFAS exposure in adults is associated with health effects over time, not acute harm from individual products. Reducing your overall PFAS load by paying attention to which products you can substitute is a reasonable harm-reduction strategy, not a survival imperative.
For most women, the practical move is to switch to verified PFAS-free options for the categories where you have the most exposure (daily-use period products, food packaging, water source if relevant) and let other categories receive less attention. Perfect avoidance is not realistic. Smarter purchasing is.
What Good Kitty Is Watching
We don't make period products at Good Kitty. We make UTI prevention supplements. But we follow this category closely because women's health is connected, and the same patterns that show up in period product contamination (industry self-policing failing, "clean" marketing not corresponding to actual product safety, regulatory gaps that leave consumers responsible for diligence) also show up in supplement contamination, cosmetic contamination, and other women's health categories.
The lessons from the PFAS work are applicable beyond period products. Look for third-party testing, demand specific verification rather than marketing claims, and trust brands that demonstrate willingness to be accountable rather than brands that simply claim to be clean. The supplement industry is no different.
For UTI Biome Shield specifically, this is why we use DMAC-verified A-type cranberry PAC content rather than vague "cranberry extract" claims. Why we use third-party testing rather than just asserting purity. Why we publish ingredient sourcing rather than hiding behind "proprietary formulations." The same standards that should apply to your period care should apply to anything else you put in or near your body.
Buy products from brands that prove their claims, not just make them.
Frequently Asked Questions
Are PFAS really in tampons and pads?
Yes, according to lab testing commissioned by the Sierra Club, Mamavation, and Environmental Health News between 2020 and 2022. The studies found organic fluorine (a PFAS marker) in 22% of tampons, 48% of sanitary pads and panty liners, and 65% of period underwear tested. Not all products contain PFAS, but the contamination rate is high enough to warrant attention to which products you choose.
Are "organic" and "natural" period products PFAS-free?
Not reliably. Mamavation testing found that 13 of 22 products marketed as "organic," "natural," "non-toxic," or "sustainable" still tested positive for PFAS in one analysis. "Clean" marketing claims do not guarantee PFAS absence. Look for specific third-party testing, OEKO-TEX certification, or Made Safe certification rather than relying on marketing language.
What health effects are PFAS linked to?
The EPA has linked PFAS exposure to decreased fertility, high blood pressure during pregnancy, increased risk of certain cancers (including kidney and testicular), developmental delays in children, hormonal disruption, elevated cholesterol, reduced immune function, and liver damage. Effects are typically associated with cumulative chronic exposure rather than single product use.
Why is PFAS in period products especially concerning?
The vaginal and vulvar tissue is highly vascularized and lacks the protective barrier that skin elsewhere on the body has. PFAS that contact vaginal tissue can be absorbed more readily than the same chemicals contacting other skin. Combined with the multi-decade exposure window (women use period products from menarche through menopause) and the daily contact with these products, the cumulative exposure can be significant.
Is there a safe level of PFAS in period products?
There's no established safe threshold for PFAS in feminine hygiene products. The EPA's 2022 drinking water health advisory set extremely low thresholds for PFOA (0.004 parts per trillion) and PFOS (0.02 parts per trillion), reflecting the fact that long-term cumulative exposure can cause harm at very low concentrations. PFAS levels found in some period products dramatically exceed these drinking water thresholds, though direct comparison is complicated by different exposure routes.
What can I do to reduce PFAS exposure from period products?
Switch to verified PFAS-free options. Look for products with OEKO-TEX certification, Made Safe certification, or specific third-party PFAS testing. Avoid products that don't provide ingredient transparency. Consider menstrual cups and medical-grade silicone discs as alternatives, which are less likely to contain PFAS than disposable products with surface treatments. Contact manufacturers directly if you can't find testing data on a specific brand.
Are reusable period products safer than disposable ones?
Mixed picture. Period underwear had the highest PFAS contamination rate in the testing (65% positive) because PFAS are sometimes used for stain resistance. Menstrual cups and silicone discs are generally lower-risk because the materials don't typically contain PFAS. Reusable cloth pads from verified PFAS-free manufacturers are also lower-risk. The reusable category itself is not inherently safer; the specific product and its manufacturing matter.
