Do moisture-wicking athletic leggings and sports bras contain PFAS or other harmful chemicals?

What's actually in it

Athletic leggings, sports bras, and moisture-wicking shirts are typically made from polyester, nylon, or spandex blends. To add sweat-wicking, odor-resistant, and stain-repellent properties, some brands treat these fabrics with PFAS coatings, antimicrobial silver nanoparticles, or biocide treatments.

When you exercise, your skin heats up and your pores open. Sweat acts as a solvent that can pull chemicals out of the fabric and into your body through the skin. Tight-fitting activewear presses directly against large areas of warm, sweaty skin, creating ideal conditions for absorption.

What the research says

A 2026 study in Environ Res found that people who wore PFAS-treated clothing had significantly higher PFAS blood levels than those who didn't. While that study focused on outdoor jackets, the same PFAS coatings appear in many activewear brands that advertise moisture-wicking or stain-resistant performance.

On top of PFAS, a 2026 review in Environ Sci Technol found that synthetic textiles shed micro- and nanoplastic fibers that can enter the body and may affect brain health. During exercise, the friction between fabric and skin accelerates fiber shedding, and the combination of heat and sweat increases chemical migration.

The chemicals of greatest concern in activewear include PFAS (forever chemicals), antimony (a metalloid used in polyester production), and various dye chemicals that can leach when heated by body warmth.

Look for activewear made from organic cotton, merino wool, or Tencel (lyocell). If you prefer synthetic performance fabrics, choose brands that certify their products as PFAS-free and OEKO-TEX certified. Wash new activewear before wearing it, and avoid wearing sweaty clothes for longer than necessary after your workout.