Is your gym attire setting you up for health problems?

Kenya’s fitness boom is putting more women in leggings, but few are asking what chemicals might be sitting against their skin.From expensive activewear sets to thrifted leggings from the secondhand clothing Gikomba market, Kenyan shoppers have little way of knowing whether their clothes contain PFAS, the so-called forever chemicals linked to hormonal and reproductive health concerns.With no specific PFAS limits for clothing, mandatory disclosure requirements or clear accountability mechanisms, women are left to trust brands without knowing what protections, if any, stand behind their purchases. Kenya’s fitness boom runs on activewear built for stretch, sweat and shine yet almost no one asks what’s actually in the fabric. By 7 a.m. on a Saturday, Riverside Square in Nairobi’s Westlands neighborhood is already filling up. Dozens arrive in matching leggings and sports bras, water bottles clipped to armbands, ready for a running loop that will most often end with coffee. Four years ago, this was the routine of four friends and a goal to keep fit. Today it is We Run Nairobi, the city’s largest free running community. On its best mornings, it pulls more than 1,200 people through the streets of Nairobi’s most upscale neighborhoods. Running clubs are only the most visible edge of a much larger shift. Fitness challenges circulate on TikTok and Instagram. Step-count groups swap targets on WhatsApp and the fitness app Step-Up. Gyms that once sat half-empty now run waitlists. At the Nairobi Bariatric Centre, a clinic that struggled to get clients when it opened three decades ago, doctors now see 10-15 patients a day. Amid this shift, reports show that nearly 90% of Kenya’s cosmetic surgery patients are women. Kenya, where carrying extra weight was once read as a sign of prosperity, is in the middle of a wellness reckoning, and the reasons are real: The World Health Organization’s Kenya office reported in 2025 that noncommunicable diseases now account for 41% of deaths and half of all hospital admissions in the country. Powering all of it, quite literally, is what people are wearing to do it in. Genio Active and Waka Women Sports are among the Kenyan activewear brands riding this movement, worn and endorsed by some of the country’s biggest influencers. A two-piece set — leggings and a matching top — runs around 7,500 shillings ($60) at Genio, which is quite expensive for most people, with the other brands pricing similarly. For many Kenyan women, that set has become shorthand for a decision: to move, to sweat, to finally take their health seriously. What almost none of them are asking is what that fabric is treated with. Women elite runners, from left, Dire Tune of Ethiopia, Caroline Kilel of Kenya, Alice Timbilili of Kenya and Sharon Cherop of Kenya, compete in the Boston Marathon, April 2011. Image by AP Photo/Michael Dwyer. Earlier this year, the Australian research body Minderoo Foundation published an investigation into a class of chemicals it found running through much of the world’s activewear: PFAS, or per- and polyfluoroalkyl substances, prized in manufacturing for their ability to repel water, oil and stains. Because of this, PFAS pose enormous threats to human health and the environment. The bond between carbon and fluorine that gives PFAS its usefulness is also what makes it almost impossible to break down — among the strongest chemical bonds known to science, according to Minderoo researcher Sarah Dunlop, which is how PFAS earned its nickname “forever chemicals.” Clothes marketed as water-resistant, odor-resistant or stain-resistant are some of the more common places PFAS turns up. And activewear, according to Dunlop, deserves particular scrutiny, not just because it is synthetic, but because of how it’s worn. It sits close to the skin. It gets hot. It gets sweaty. And heat, friction and perspiration are exactly the conditions that speed up how much of a chemical the skin absorbs. It remains unclear how routine exposure to these chemicals through clothing affects long-term human health, and scientists call for further research in this area. “Textiles represent a significant and underestimated source of daily chemical exposure. While acute effects like allergies are recognized, the long-term systemic health consequences of chronic, low-dose exposure to complex chemical mixtures in clothing remain largely uncharacterized and potentially substantial,” according to a 2025 study in the Journal of Environmental Science and Health, Part A. Girls compete in a lap race during high school games in a school in Kenya. Image by Onlyonestef via Wikimedia Commons (CC BY-SA 4.0). PFAS risks extend to the environment as well. A 2026 review in Environmental Pollution, synthesizing global research, found PFAS contamination across all three major environmental systems: air, water and soil, with concentrations particularly high near industrial sources. But what should make any consumer pause is that most wastewater treatment simply does not remove PFAS. It does not break down. It accumulates — in soil, in waterways, in the human body, where it has been linked to endocrine disruption, immune dysfunction and toxicity across multiple organs. A 2025 policy brief in the Journal of Science Policy & Governance (JSPG) traces exactly how that happens in textiles specifically. More than half of all global PFAS use, the brief notes, goes into waterproof coatings for fabric. Once released, during manufacturing, through wear and tear, at disposal, PFAS behave as an endocrine and genetic disruptor in the wider environment. In aquatic ecosystems, it has been linked to lower egg-hatching success and offspring deformities in fish, according to the brief. It has also been detected in crops and livestock raised near contaminated water. Kenya already has a documented entry point into that cycle. A cross-country study examining PFAS contamination across 11 African countries, names the Nairobi River as one of the continent’s PFAS hotspots, alongside Lake Victoria and South Africa’s Vaal River. Kenya is a signatory to the Stockholm Convention, the global treaty aimed at eliminating persistent pollutants like PFAS. According to the researchers, enforcement across signatory African countries remains weak, and none of the contamination they mapped has been traced back to a specific consumer product category, activewear included. In the United States, the pushback against PFAS in clothing has moved from research paper to statute in some locations. California’s Safer Clothes and Textiles Act and New York’s apparel PFAS ban, both effective January 2025, prohibit the sale of new textiles containing intentionally added PFAS above a set threshold. Colorado has taken a lighter-touch approach, requiring outdoor brands to disclose PFAS use on the label rather than banning it outright, for now. A full ban is scheduled to follow in 2028. Brands are responding unevenly. Patagonia, a designer of outdoor and sportswear, announced in 2025 that its clothing no longer intentionally contains PFAS, while acknowledging it cannot yet guarantee a fully PFAS-free supply chain. Gore-Tex, by contrast, is facing a class-action lawsuit alleging it marketed itself as newly PFAS-free while the claim applied only to future product lines — not the gear already on shelves. Cameroonian weightlifter Clementine Meukeugni Noumbissi during the 2021 Islamic Solidarity Games. Image by Astro medya Org. Ltd. ŞTİ. via Wikimedia Commons (CC BY 2.0). Researchers at the University of Leeds and Bristol in the U.K. have found non-fluorinated water-repellent finishes that perform comparably to PFAS, evidence that an industry built on the chemical does have somewhere else to go, if it chooses. Kenya has none of this. No ban. No disclosure requirement. No labeling standard equivalent to OEKO-TEX, GOTS or bluesign, the certifications Minderoo’s researchers point consumers toward elsewhere. In an email to Mongabay, Stephen Mutoro, secretary general of the Consumer Federation of Kenya, said that very little currently protects women buying new or thrifted leggings in Kenya from PFAS exposure. “Kenya has no specific PFAS limits for clothing, leaving shoppers with little protection and unclear accountability when products are found to contain harmful chemicals.” He added that most consumers do not know where to lodge complaints. Mutoro identified mandatory disclosure labeling as the first realistic step, arguing that shoppers deserve to know what they are wearing. He recommended that the Kenya Bureau of Standards (KEBS) subsequently strengthen import testing and recognize credible certification schemes such as OEKO-TEX, GOTS and bluesign. However, the cost of testing, limited laboratory capacity and low public awareness remain significant barriers to closing the regulatory gap. Much of the country’s gym wear moves through two channels: thrifted, via Gikomba market, Kenya’s largest open-air secondhand textile market; or bought new from local brands shipping in bulk. Neither pathway currently requires a company to say whether what it’s selling contains PFAS, and neither is required to say whether the product has passed through the Kenya Bureau of Standards in a way that would answer the question either. In a chat conversation with Genio Activewear via Instagram, Mongabay asked, “Could you confirm if this set is PFAS free?” and the brand responded, “Absolutely, you have nothing to worry about. All our active wear fabrics are made without PFAS or any harmful chemicals.” Waka Women sport did not respond when the same question was posed. Mongabay contacted the Kenya Bureau of Standards (KEBS) via its toll free number 1545 and email to enquire whether it currently tests imported or locally made clothing for PFAS, if there is a Kenyan standard that sets the limit for PFAS in textiles and if any company selling activewear in Kenya is required to verify or disclose chemical treatments on its garments or to prove if they are PFAS free. By the time of publication, KEBS had not formally responded via email, as its communications team maintains that answers to these questions must get approval. However, in a phone call, Mercy Kandie, the communications officer at KEBS, said that KEBS has the largest lab in East and Central Africa, with a specific section that is dedicated to testing plastics. They also added that standards are ever evolving, and Kenya has a law that requires the bureau to review standards every two years. They didn’t specify what law, but promised that detailed answers will be communicated via email, which Mongabay is yet to receive. Women in a sport training session in Zambia. Image by Francis ackson soko via Wikimedia Commons (CC BY-SA 4.0). The health stakes sharpen further when they meet a conversation already underway in Kenya. Polycystic ovary syndrome (PCOS) — increasingly referred to in the medical literature as polyendocrine metabolic ovarian syndrome, or PMOS, following a global consensus process published in The Lancet in 2026 that recognized the condition’s broader hormonal and metabolic dimensions — has become one of the more visible health conversations in Kenyan media in recent years, discussed by public figures and ordinary women alike, often in the same breath as fertility struggles. The JSPG policy brief lays out, with citations, why PFAS belong in that conversation. Documented associations include PCOS, endometriosis, ovarian tumors, gestational diabetes, preeclampsia and preterm birth, with suggestive evidence tying PFAS to infertility and failed IVF cycles — the chemical has been found present in follicular fluid itself. One striking detail from the research: Because women partially excrete PFAS through menstruation, one modeled study found women’s elimination half-life for a common PFAS compound was shorter than men’s. But that is not the reprieve it sounds like. PFAS also passes to the next generation through the placenta and through breast milk — not eliminated, so much as handed down. None of this proves that any individual woman’s PCOS, or PMOS, was caused by her leggings. The research describes a population-level association and a documented exposure pathway, not a diagnosis. But it does mean that a chemical class already linked to the condition driving so much of Kenya’s current health conversation may be sitting, unexamined, against the skin of the women having that conversation, while they sweat, while they stretch, while they do exactly what they were told would make them healthier. None of this is an argument against running, or against the women filling Riverside Square every Saturday morning, or against wanting, quite reasonably, to feel strong in your own body. It’s an argument for the right to know what you’re putting on it. Right now, in Kenya, that right doesn’t exist, not because the science hasn’t caught up, but because no one has been asked to test, disclose or certify. Banner image: Two women walk together at a marathon. Image by Steward Masweneng via Unsplash. Citations: Rovira, J., Souza, M. C. O., Nadal, M., & Domingo, J. L. (2025). Human health risks from textile chemicals: a critical review of recent evidence (2019–2025). Journal of Environmental Science and Health, Part A, 60(2), 79–91. https://doi.org/10.1080/10934529.2025.2514406 Zhang, Z., Liu, Y., Chen, Y., Qu, H., Ma, J., Pang, M., … Yu, G. (2026). Per- and polyfluoroalkyl substances in the environment and human tissue: A critical review of distribution, exposure pathways, and health risks. Environmental Pollution, 397, 127988. doi:10.1016/j.envpol.2026.127988 Greenland, E., & Lewis, R. (2025). The dangers of PFAS in the textile industry: Proposed policy approaches. Journal of Science Policy & Governance, 27(1). doi:10.38126/jspg270104 Credits Topics