Bisphenol A (BPA), a chemical commonly used in plastics and textiles, has raised alarms due to its potential endocrine-disrupting effects. Recent studies and reports highlight its presence in clothing, particularly athletic wear made from polyester and spandex. This report delves into the evidence on BPA absorption through the skin, with a focus on heightened risks during exercise when heat and sweat open pores and facilitate chemical leaching. Drawing from scientific research, consumer watchdogs, and health assessments, we explore exposure levels, health implications, and mitigation strategies. While exposure from clothing is generally lower than dietary sources, sweaty conditions can elevate risks, prompting calls for better regulations and consumer awareness.

Introduction to BPA and Its Presence in Textiles

BPA is a synthetic compound used in manufacturing polycarbonates, epoxy resins, and increasingly in textiles for durability and flexibility. It’s found in everyday clothing, but concentrations are notably higher in synthetic activewear like sports bras, leggings, shirts, and shorts. Studies show BPA migrates from fabrics into sweat, potentially entering the body via dermal absorption. This migration is amplified under “wet” conditions, such as during exercise, where sweat simulates a leaching environment similar to artificial sweat tests in labs. Research indicates BPA is detected in 91-99% of tested clothing samples, with levels ranging from <0.050 ng/g to over 2,474 ng/g for BPA and its analogs like BPS. Recycled textiles often contain higher median BPA (13.5 ng/g) compared to conventional ones (7.66 ng/g), reflecting a shift in manufacturing but also raising concerns about recycled materials concentrating contaminants. Brands like Athleta, Nike, The North Face, Patagonia, and others have been implicated in tests showing BPA up to 40 times California’s safe harbor limit under Proposition 65 (3 mcg/day via skin).

Mechanisms of Skin Absorption and the Role of Exercise

Skin absorption of BPA occurs rapidly—studies on receipt paper handling show it enters the bloodstream in seconds to minutes. During exercise, several factors exacerbate this:

• Sweat and Heat: Perspiration creates a moist environment that enhances BPA leaching from fabrics. Lab simulations using artificial sweat show migration rates of 0.049–0.308 (5–31% leaching in 2 hours), higher in synthetics than natural fibers. High body temperature activates this process, as BPA leaches more readily when exposed to water or heat.
• Open Pores: Exercise-induced sweating dilates pores, increasing skin permeability and potential uptake. Dermal exposure under wet conditions can exceed dry scenarios by over 1,000-fold in some analogs.
• Prolonged Contact: Activewear is worn for hours, tightly against the skin, amplifying exposure compared to brief contacts. Unlike ingested BPA, which is quickly metabolized and excreted, dermally absorbed BPA lingers longer in the body.

A 2024 study on 57 textile samples (T-shirts and socks) found that while dry exposure stays below the European Food Safety Authority’s (EFSA) tolerable daily intake (TDI) of 0.2 ng/kg body weight/day, wet/sweaty conditions often surpass it—up to 114 ng/kg bw/day or 125–570 times the TDI in extreme cases. Another study estimated adult exposure from sweaty clothes at 1.56–9.90 ng/kg bw/day, and higher for toddlers (2.37–14.8 ng/kg bw/day) including oral mouthing.

Key Reports and Studies

Several pivotal reports underscore these risks:

• Scientific Committee on Consumer Safety (SCCS) Opinion (2022): Assessed BPA in clothing, noting median concentrations of 11–27 ng/g and up to 252 ng/g in non-EU samples. Migration to sweat was tested, yielding conservative exposure estimates but highlighting uncertainties in long-term leaching. No adverse effects expected, with a margin of safety over 900, but more studies needed.
• Center for Environmental Health (CEH) Testing (2022–2023): Independent tests on brands like Nike, Patagonia, and Under Armour revealed BPA exceeding safe limits by 22–40 times. Emphasized absorption risks during sweaty workouts, compounding other exposures.
• Jurikova et al. (2024): Analyzed conventional vs. recycled textiles, showing washing reduces BPA by 30–70% but doesn’t eliminate it. Wet conditions pose higher risks, exceeding TDI thresholds.
• Other Insights: A 2015 biomonitoring study explored BPA in sweat via patches worn for 7 days, suggesting it could measure multiday exposure from sources like clothing. Media reports from outlets like Runner’s World and Outside Magazine echo concerns, noting sweat pulls chemicals from fabrics.

Health Implications BPA mimics estrogen, potentially disrupting metabolism, growth, reproduction, and increasing risks for conditions like obesity, diabetes, and certain cancers—even at low doses. While clothing exposure is 25+ times lower than dietary, combined sources could amplify effects, especially for vulnerable groups (e.g., pregnant individuals, children). Experts like Ana Soto from Tufts University warn of cumulative impacts. However, some assessments find no immediate risk, with margins of safety (MoS) over 900.

Recommendations

To minimize exposure:

• Choose natural fibers like organic cotton over synthetics.
• Wash new clothes multiple times before use to reduce BPA.
• Opt for BPA-free certified brands.
• Advocate for stricter regulations on textiles, similar to food contact materials.
• Further research on analogs (e.g., BPS) and long-term dermal effects is crucial.

While BPA in clothing poses low overall risks, exercise scenarios heighten absorption through open pores and sweat-induced leaching, potentially exceeding safety thresholds in worst cases. Consumer vigilance and industry shifts toward safer materials are essential to sweat without the added toxins.

 

Citations

[0] Bisphenols in daily clothes from conventional and recycled material: evaluation of dermal exposure to potentially toxic substances – PMC – https://pmc.ncbi.nlm.nih.gov/articles/PMC11415442[1] New Testing Shows High Levels of BPA in Sports Bras and Athletic Shirts – https://ceh.org/latest/press-releases/new-testing-shows-high-levels-of-bpa-in-sports-bras-and-athletic-shirts[2] Opinion of the Scientific Committee on Consumer Safety on BPA in clothing – Language selection | Public Health – https://health.ec.europa.eu/system/files/2022-08/sccs_o_240.pdf[3] High levels of BPA found in sports bras, according to new report – https://www.mother.ly/health-wellness/womens-health/bpa-in-sports-bras[5] Even More Athletic Brands Have BPA in their Products, According to Watchdog Group – https://www.runnersworld.com/news/a41781827/bpa-in-sports-bras-athletic-wear[7] According to a recent report from the Center for Environmental Health, sports bras can … – https://www.facebook.com/mommypotamus/posts/according-to-a-recent-report-from-the-center-for-environmental-health-sports-bra/1407191264102299[8] A Preliminary Study of Biomonitoring for Bisphenol-A in Human Sweat – PMC – https://pmc.ncbi.nlm.nih.gov/articles/PMC9248020[9] Scientists Found BPA in Sports Bras and Shirts. Should You Be Worried? – https://www.outsideonline.com/outdoor-gear/gear-news/bpa-sports-bras-news