The Chemicals in Your Gym Clothes That Nobody Talks About
You've thought about what you eat. You've thought about what you drink. Almost nobody has thought about what they wear.
The fitness industry has trained gym-goers to obsess over ingredients. What's in the protein powder. What's in the pre-workout. Whether the creatine is micronised.
The activewear sitting right against your skin for an hour or more per session, soaking in sweat, generating friction, being washed and re-worn hundreds of times over years of training, has largely escaped that same scrutiny.
It shouldn't have.
What PFAS Are and Why They're in Your Gym Kit
PFAS, per- and polyfluoroalkyl substances, are a class of roughly 12,000 synthetic chemicals used across consumer products for their water-resistant, stain-resistant, and quick-drying properties. They earned the name "forever chemicals" because they don't break down in the environment or in the human body. They accumulate over time.
They're in most performance activewear:
A Washington Post investigation published in April 2026 found PFAS in popular workout and athletic wear across major brands. Independent testing by Mamavation, an environmental health organisation, tested 32 pairs of workout leggings from well-known brands and found widespread PFAS presence. Most brands that promised to phase out PFAS by 2020 still show traces in current products.¹
The label won't tell you:
Labels list fabric content and care instructions. They do not disclose PFAS or other chemical treatments. Terms like "water-resistant," "stain-repellent," or "quick-drying" may indicate PFAS treatment, but no explicit disclosure is required under most regulatory frameworks outside California and a small number of US states that have begun restricting intentionally added PFAS from 2025.¹
The phase-out problem:
When a brand announces a "phase-out year," it typically means new production stopped. Existing inventory continues moving through retail channels for months or years afterward. A company can also eliminate one PFAS compound and still use dozens of structurally similar alternatives from the same class of 12,000 chemicals, each of which may carry similar properties.²
Why Exercise Specifically Makes This Worse
Sweat is a solvent:
A 2025 study on dermal transfer of PFAS from textiles found that sweat can increase chemical absorption up to 3,252 times compared to dry contact with the same fabric. The very thing that makes activewear useful, managing sweat during high-intensity exercise, is also the condition under which it becomes most chemically permeable.³
Increased blood flow accelerates absorption:
During exercise, blood flow to the skin surface increases substantially. Whatever is absorbed through the skin during a workout reaches the circulatory system faster and more completely than it would at rest.
Duration compounds exposure:
A 60 to 90 minute training session in synthetic activewear is a sustained, high-sweat, high-friction exposure event. Repeated across five training days a week, fifty weeks a year, for years of consistent training, the cumulative exposure picture looks different from a single casual wear.
What PFAS Exposure Has Been Linked To
The EPA formally designated PFOA and PFOS, two of the most studied PFAS compounds, as hazardous substances under Superfund law in 2024, a classification that requires substantial scientific evidence. Peer-reviewed research has linked PFAS exposure to thyroid disruption, immune function impairment, kidney and testicular cancer, elevated cholesterol, and reduced fertility. Attorneys general from 30 US states and the District of Columbia have initiated litigation against PFAS manufacturers.²
The research does not establish a single gym session in polyester leggings as a health crisis. What it does establish is that chronic, repeated dermal exposure to PFAS-treated fabrics during sweating is a real and measurable exposure pathway, not a theoretical one.
What This Has to Do With DEVOTED
The shaker was the starting point because it was the highest-frequency food-contact variable we could control. The clothing question is the next one.
We're not ready to say more about that yet. But the standard we apply to what goes against your skin is the same one we apply to what goes inside your body, and that standard rules out the same category of defaults the activewear industry has been living with for decades.
Watch this space.
Sources
- PFAS Free Life, April 2026. "PFAS in Workout Clothes: What Your Activewear Is Not Telling You." Citing a Washington Post investigation (April 21, 2026) finding PFAS in popular workout and athletic wear, and noting that Maine joined California in 2026 with its own restriction on PFAS in apparel. Only "intentionally added" PFAS are covered by current bans, meaning trace contamination from manufacturing can pass through undetected. URL: https://learn.pfasfreelife.com/research/pfas-in-workout-clothes-what-your-activewear-isnt-telling-you
- NonToxicLab, April 2026. "The Lululemon PFAS Investigation: What It Means and Which Activewear Is Actually Safe." Covers the EPA's 2024 Superfund hazardous substance designation for PFOA and PFOS, the 30-state litigation against PFAS manufacturers, and the limitation of brand "phase-out" pledges when PFAS is a class of roughly 12,000 chemicals rather than a single substance. URL: https://nontoxiclab.com/lululemon-pfas-activewear-investigation/
- FiberCheck, May 2026. "Are Your Gym Clothes Toxic? PFAS, BPA & Hidden Chemicals in Activewear." Citing a 2025 study on dermal transfer of PFAS from textiles finding sweat can increase chemical absorption up to 3,252-fold compared to dry contact. Also confirms exercise amplifies absorption because increased blood flow to the skin surface accelerates how quickly absorbed chemicals enter circulation. URL: https://fibercheck.app/blog/are-gym-clothes-toxic-pfas-bpa-chemicals-activewear/
