PFAS in sportswear: the 'forever chemicals' you wear daily

We wear sportswear almost daily: leggings, yoga pants, running jackets. They need to be comfortable, breathable, and above all: sweat- and dirt-repellent. But precisely this last point has a downside. Many of these "high performance" garments contain PFAS – the notorious 'forever chemicals'. Substances that barely break down in the environment, accumulate in our bodies, and are increasingly linked to health problems such as hormonal disruption and reduced fertility.

What are PFAS?

PFAS stands for per- and polyfluoroalkyl substances. It is a group of thousands of synthetic chemicals used for their water, grease, and dirt-repellent properties. They are applied in everything from non-stick pans to fire-fighting foam. And also in sports and outdoor clothing.^[1]

Why? Because PFAS ensure your leggings don't get wet from sweat, your jacket stays waterproof, and your sports shirt stains less easily. These chemicals contain extremely strong carbon-fluorine bonds that are almost indestructible – hence the nickname "forever chemicals."^[2]

PFAS in sportswear: how common is it?

Research shows that much sports and outdoor clothing contains PFAS. A 2022 study tested clothing and found high concentrations of PFAS in water-repellent sports and children's clothing. Even school uniforms were found to be contaminated with fluorine chemicals.^[3] The study found PFAS in 72% of the tested water-repellent garments, with concentrations sometimes exceeding safety limits.

In 2023, the European Chemicals Agency (ECHA) reported that PFAS in textiles and clothing is a significant source of environmental pollution, due to leaching during wear and washing.^[4] An independent investigation by Toxic-Free Future found that 60% of tested outdoor clothing brands contained significant levels of PFAS.^[5]

NGOs such as ChemSec and Greenpeace have repeatedly found PFAS in outdoor clothing brands, even in products marketed as "eco-friendly."^[6]

What does PFAS do in your body?

PFAS are called 'forever chemicals' for a reason. They barely break down and can circulate in the human body for years. The half-life of some PFAS in human blood is between 2 and 9 years – meaning that exposure today can still have effects a decade later.^[7] Scientific studies show:

Fertility: Higher PFAS levels in blood are linked to a longer "time-to-pregnancy" in women and a lower chance of conception.^[8] One study found that women with the highest PFAS levels had a 40% lower chance of pregnancy within a year compared to women with the lowest levels.^[9]

Hormones: PFAS can disrupt the production and function of estrogen and testosterone. Research shows that PFAS interfere with steroid hormone synthesis and are associated with lower testosterone levels in men.^[10]

Immune system: According to the US National Academies of Sciences, PFAS weaken the immune system and reduce response to vaccinations.^[11] Studies show that children with higher PFAS exposure had significantly lower antibody concentrations after vaccinations.^[12]

Cancer: The US EPA classifies certain PFAS (PFOA) as carcinogenic.^[13] Epidemiological research has found links between PFAS exposure and an increased risk of kidney and testicular cancer.^[14]

Thyroid: PFAS disrupt thyroid function, which can lead to metabolic problems and weight gain. A meta-analysis found consistent associations between PFAS and reduced thyroid hormone levels.^[15]

How do PFAS from clothing enter your body?

PFAS are found in coatings and finishes on textiles. During wear, sweating, and washing, these substances detach and can:

Migrate onto the skin – especially with heat and sweat, such as during exercise. Recent research showed that PFAS can migrate from textiles to artificial sweat and be absorbed through the skin.^[16] At body temperatures between 35-40°C – normal during intense exercise – migration increases significantly.

Be inhaled – microfibers with PFAS are released into the air and inhaled. Studies show that PFAS-containing dust in households is an important exposure route, especially in areas where a lot of synthetic sportswear is stored and worn.^[17]

Leach out during washing – PFAS end up in wastewater, where they are barely removed by conventional water treatment systems. A study found that one wash of water-repellent clothing can release up to 1.3 micrograms of PFAS.^[18]

Why isn't anyone talking about this?

PFAS in clothing is a blind spot in the fashion industry. While we discuss microplastics and CO₂, the discussion about forever chemicals remains limited. Brands rarely communicate whether their coatings are PFAS-free. Moreover, there is hardly any regulation – although that is changing.

A 2024 study found that less than 15% of clothing brands offer transparency about the use of PFAS in their products, despite growing awareness of the health risks.^[19]

PFAS regulations: Europe takes action

EU ban in preparation: In 2023, five countries (including the Netherlands) presented a proposal for a total European ban on PFAS in consumer products, including textiles.^[4] This proposal could prohibit the production, sale, and use of PFAS in textiles within the EU from 2026-2028.

OEKO-TEX® 2024: Since 2024, this certification applies a total fluorine limit, which should exclude PFAS in certified clothing.^[20] The limit is set at 1 μg/m² (extractable organic fluorine), a significant tightening.

GOTS certification: The Global Organic Textile Standard prohibits the use of PFAS in all production steps. GOTS-certified clothing must not contain fluorine-containing chemicals in coatings, finishes, or treatments.

How GOTS and OEKO-TEX protect against PFAS

PFAS – the "forever chemicals" we just discussed – are precisely what GOTS and OEKO-TEX Standard 100 protect against. These certifications offer different but complementary protection against PFAS exposure through sportswear.

The difference in approach: GOTS completely prohibits PFAS during the production process, while OEKO-TEX 100 tests the final product to ensure that PFAS residues remain below detectable levels. For organic cotton sportswear with both certifications, this means absolute certainty: no PFAS during production and a tested final product.

What can you do as a consumer?

Check certifications

Choose OEKO-TEX® Standard 100, GOTS, or Bluesign®, which prohibit or severely restrict PFAS. These certifications are independently verified and offer genuine guarantees.

Pay attention to claims

Avoid sportswear that claims to be "stain-resistant," "waterproof," or "easy care" without further explanation. There's a good chance it contains PFAS. If a brand is transparent about PFAS-free alternatives, they usually state this explicitly.

Ask brands for transparency

More and more consumers are demanding PFAS-free collections. Brands only respond if there is high demand. Send an email, ask in stores, share on social media – collective action works.

Choose natural materials

Organic cotton, hemp, and merino wool are naturally breathable and do not require chemical coatings. They regulate moisture naturally without harmful chemicals.

Wash less often

If you own PFAS-containing clothing, wash it less often. Each wash leaches more PFAS into the wastewater and weakens the coating, releasing more PFAS during wear.

Conclusion

PFAS are the hidden chemical layer in many sports and outdoor clothes. They might make your leggings water-repellent, but the price is high: chemicals that don't break down, accumulate in your body, and pose risks to fertility, hormones, and your immune system.

The science is clear, regulations are coming – but as long as brands keep this problem quiet, it's up to consumers to make conscious choices. At NOHI NATURAL, we exclusively use GOTS-certified organic cotton. No water-repellent coatings, no forever chemicals – just natural materials that are breathable without chemical tricks.

Because the true performance of sportswear should be: keeping you healthy, not making you sick.