Leggings are not inherently bad for your health. The answer to that question depends almost entirely on what the leggings are made of, and that is a question most people have never thought to ask.
For women making the shift to non-toxic workout clothes, leggings are usually the first garment worth examining, because they cover more skin surface area for longer than almost any other item in a workout wardrobe.
The Synthetic Default
The vast majority of leggings on the market are made from polyester, nylon, spandex, or blends of those three materials. All are synthetic polymers, meaning plastics in fiber form. That baseline matters for two reasons: microplastic shedding and chemical finishing.
On microplastics: synthetic leggings shed plastic microfibers during wear and washing. Napper and Thompson (2016), in Marine Pollution Bulletin, documented consistent microfiber release from synthetic fabrics under standard domestic washing conditions. Shedding during wear, through friction and movement, has also been documented. For leggings specifically, which are worn in full-leg contact with the skin for extended periods, that shedding happens in sustained direct contact with a large surface area of the body.
On chemical finishing: many synthetic leggings are treated with durable water repellent coatings, stain resistance treatments, and odor-control finishes that introduce PFAS or other chemical inputs that are not disclosed on the fiber content label. The EPA has linked PFAS exposure to thyroid disruption, immune suppression, and elevated cancer risk based on human epidemiological data.
The Lululemon Investigation as a Reference Point
In April 2026, the Texas Attorney General opened a civil investigation into Lululemon over the potential presence of PFAS in its activewear. Lululemon confirmed it had used PFAS in its durable water repellent products before phasing them out in early 2024. A class action lawsuit in California made parallel allegations about misleading sustainability marketing while PFAS were present in the product.
The case matters as a reference point because Lululemon is not a discount brand. It is the premium end of the leggings market, positioned on wellness, performance, and quality. If PFAS chemistry was standard practice there through 2024, it was not an outlier. It was the industry norm.
Compression and Circulation
There is a separate, non-chemical concern about leggings worth addressing: compression. Leggings worn too tight, particularly around the waist and abdomen, can restrict circulation and compress the lateral femoral cutaneous nerve, a condition sometimes called meralgia paresthetica, which causes numbness, tingling, or pain in the outer thigh.
This is a fit issue, not a fabric issue, and it is worth distinguishing from the chemical exposure questions above. Well-fitted leggings that do not compress uncomfortably are not causing circulatory harm.
Breathability and Bacterial Environment
Synthetic leggings are hydrophobic, meaning they repel moisture rather than absorbing it. Sweat sits on the surface of the fabric rather than being drawn away from the skin, creating a warm, moist environment that supports bacterial and yeast growth. This is the mechanism behind the persistent odor that develops in synthetic activewear over time, and it is also relevant to skin and vaginal health for people wearing synthetic leggings during extended workouts.
TENCEL Lyocell behaves differently. The fiber is hydrophilic, absorbing moisture into its core structure rather than leaving it on the surface. Kaplan et al. (2014), in Fibers and Polymers, documented TENCEL's superior moisture management and thermal comfort compared to synthetic fibers in active wear settings. Reduced surface moisture means a less hospitable environment for the bacteria and yeast that cause odor and contribute to skin and vaginal irritation.
What Makes a Legging Lower-Risk
Three things determine the health profile of a legging more than any other factor: the base fiber, the chemical finishing treatments applied to it, and whether either has been independently verified.
A legging made from TENCEL Lyocell rather than polyester or nylon starts from a categorically different chemical baseline. No petroleum-derived polymer chemistry, no plastic microfiber shedding profile, and structural moisture management that reduces the need for chemical odor-control treatments. Bellissima's Sempre Leggings are 92% TENCEL Lyocell and 8% spandex, with the spandex content stated clearly because the full composition is what matters, not just the headline fiber.
The Actual Answer
Are leggings bad for your health? Most leggings currently on the market are made from synthetic fibers with chemical finishing histories that have not been transparently disclosed, worn in conditions that favor both microplastic shedding and chemical migration toward the skin. That is a reasonable basis for asking what your leggings are made of and whether any of it has been independently verified. For a deeper look at the yoga pants angle specifically, whether yoga pants are toxic covers the PFAS evidence in detail. For how this connects to hormones, whether activewear affects your hormones covers the endocrine disruption mechanisms. And for a complete evaluation framework, the non-toxic activewear buying guide covers what to look for at every step.
Sources
Texas Attorney General. (2026, April 13). Attorney General Ken Paxton Launches Investigation into Lululemon Over Potential Presence of Toxic Forever Chemicals in Activewear. texasattorneygeneral.gov.
U.S. Environmental Protection Agency. (2024). Our Current Understanding of the Human Health and Environmental Risks of PFAS. EPA.gov.
Napper, I.E., and Thompson, R.C. (2016). Release of synthetic microplastic plastic fibres from domestic washing machines. Marine Pollution Bulletin, 112(1-2).
Leslie, H.A., et al. (2022). Discovery and quantification of plastic particle pollution in human blood. Environment International, 163.
Kaplan, S., et al. (2014). Thermal comfort of lyocell and other fibers in active wear. Fibers and Polymers, 15(6).
