What Are the Hidden Dangers Within Synthetic Activewear?
When plastic fibres meet friction, heat, and sweat, they can create hovic on your body's natural state. This article reveals the hidden risks of synthetic activewear and how to choose safer, non‑toxic alternatives.
In 2022, I came across a shocking video revealing that tests on popular leggings brands detected "forever chemicals", with particularly high concentrations in the crotch area. Considering that many people wear leggings without underwear, and given our knowledge of chemical leaching, the potential health risks are concerning.
Activewear has undergone significant development in recent years, with many synthetic fibres offering buttery-soft finishes, moisture-wicking attributes, body sculpting, stretch and the compression we need for high-impact activity.
But synthetic fibres are essentially plastic. Man‑made substances derived from fossil fuels, extracted and refined to create durable, non‑biodegradable materials.
It’s now widely accepted that toxic chemicals from plastics can leach into your food and drink, but the same concern now applies to what you put on your skin.
Many brands have turned to recycled plastics to develop more sustainable activewear, often with good intentions in reducing waste - but the idea of wrapping our bodies in plastic has never felt right, and the emerging science is beginning to validate this.
It's a cruel irony that in the pursuit of being healthy and detoxifying our bodies through exercise, we may instead be increasing our toxic load by wearing materials that do the opposite.
Absorption of Forever Chemicals Through Skin
Your skin is your largest organ, and while it is designed to protect, it is not a perfect barrier. Think about how skincare products, topical pain relief, or even nicotine patches work. They penetrate the skin and are absorbed into the body.
Scientific evidence now shows that it's our sweat, especially its oily components, that can draw out lipophilic (fat-attracted) chemicals like BPA and phthalates from synthetic fabrics. Once released, these substances can be absorbed into the bloodstream.
The combination of plastic fabrics worn close to the body, plus friction, heat, and sweat, creates the perfect conditions for chemicals to leach out and disrupt the body’s natural balance.
This is exactly what happens during high-intensity exercise, and once absorbed, PFAS, BPA, and phthalates can interfere with hormone signalling, bind to cellular receptors, and alter hormone production.
Research in both humans and animals has linked these chemicals to negative metabolic effects, and certain PFAS have even been associated with an increased risk of cancer.
Forever Chemicals Overview
PFAS linked to hormone disruption, cancer risk
BPA an endocrine disruptor often found in plastic coatings
Phthalates used to soften plastics, known to interfere with hormones
And then there is the microplastic problem.
Synthetic Clothing Releases Microplastics
Every time synthetic clothing is worn and washed, it sheds tiny fragments called microplastics.
These particles travel through air, evade water treatment systems, and settle in oceans, soil, and eventually our food chains.
A single laundry load of synthetic garments can release hundreds of thousands of microfibres into the water, with dryers also venting out these plastics into the air, not to mention how friction during wear sheds fibres into the air and dust.
How do microplastics affect human health?
Terrifying statistics are coming out on how much of the world is now polluted with microplastics.
Studies have detected microplastics in human lungs, placenta, and bloodstream. In one study published in 2022, nearly four in five participants had detectable microplastics in blood.
Once plastic reaches your organs, there’s no natural way for it to escape.
Particles can lodge in tissues, generate inflammation and oxidative stress, and act as carriers that concentrate and transport other toxic chemicals into the body.
So what can we do to help prevent this toxic build-up in our bodies? And what does this mean for synthetic activewear?
How to Choose Safer Activewear
1. Check the fabric composition and choose natural fibres wherever possible
Opt for organic cotton, bamboo, hemp, merino wool, natural rubber, TENCEL™, and bio‑based elastanes wherever you can. These elastanes aren’t perfect, but they’re a better option than conventional synthetics.
It’s extremely difficult to recreate the compression and strength of synthetic fibres in activewear, which is why small amounts of elastane are often still used.
2. Check certifications
Look for OEKO-TEX® or GOTS labels to ensure garments have been tested for harmful substances.
3. Avoid coatings and finishings
Steer clear of terms like “anti-odour,” “stain-resistant,” or “moisture-wicking” unless they come with clear, non-toxic certifications or natural fabrics (like the ones mentioned above).
4. Wash consciously
Use cold water. And if you want to level up, you could consider buying a microfibre-filtering laundry bag to reduce plastic shedding.
5. Dry smarter
Air dry whenever possible. If using a dryer, make sure it vents outdoors to avoid breathing in the microplastics that get expelled into the air from the vent.
6. Retire worn-out gear
Old synthetic fabrics shed the most microplastics and can leach even more chemicals. When items reach the end of their life, check if they can be recycled through brand take back schemes or textile recycling programs. Choosing natural fibre replacements will support biodegradation which is kind to the planet.
Final Thoughts
What we are exposed to every day matters most. Unfortunately, the way our modern world works means there is a lot that is out of our control. But by asking the right questions and learning about risks, we can arm ourselves with knowledge to demand safer products and higher industry standards.
Read our article on simple, practical changes you can control to reduce your toxic load in other areas of life. Many of these are small, actionable steps you can implement immediately to ease the burden on both your body and the planet.
Every small choice adds up, and each change you make is an investment in your health, your future, and a cleaner world.
References
Carrington, D. (2022, March 24). Microplastics found in human blood for first time. The Guardian. https://www.theguardian.com/
Center for Environmental Health. (2022, October 12). New testing shows high levels of BPA in sports bras and athletic shirts. https://ceh.org/
European Environment Agency. (2022). Microplastics from textiles: Towards a circular economy for textiles in Europe. https://www.eea.europa.eu/
Li, H.-L., Ma, W.-L., Liu, L.-Y., et al. (2019). Phthalates in infant cotton clothing: Occurrence and implications for human exposure. Science of the Total Environment, 683, 109–115. https://doi.org/10.1016/j.scitotenv.2019.05.132
Abdallah, M. A.-E., et al. (2023). Chemical transfer from synthetic textiles into human skin under realistic conditions. Journal of Hazardous Materials, 443, 130155. https://doi.org/10.1016/j.jhazmat.2022.130155
Centers for Disease Control and Prevention. National biomonitoring data on PFAS in human blood, United States.
International Agency for Research on Cancer. Carcinogenicity classifications for PFOA and PFOS.
Grandjean, P., et al. Studies linking PFAS exposure with reduced vaccine antibody responses in children.
European Chemicals Agency. Proposals and assessments regarding PFAS restrictions in consumer products.
Leslie, H. A., et al. Microplastics detected in human blood, Environment International, 2022.
Studies reporting microplastics in human lung tissue and placenta in clinical samples.
International Union for Conservation of Nature. Primary microplastics in the oceans and textile fibre contributions.
Napper, I. E., and Thompson, R. C. Quantification of microfibre release during domestic laundering.
Epidemiologic and toxicologic literature on BPA and phthalate exposure, endocrine and reproductive endpoints.
In 2022, I came across a shocking video revealing that tests on popular leggings brands detected "forever chemicals", with particularly high concentrations in the crotch area. Considering that many people wear leggings without underwear, and given our knowledge of chemical leaching, the potential health risks are concerning.
Activewear has undergone significant development in recent years, with many synthetic fibres offering buttery-soft finishes, moisture-wicking attributes, body sculpting, stretch and the compression we need for high-impact activity.
But synthetic fibres are essentially plastic. Man‑made substances derived from fossil fuels, extracted and refined to create durable, non‑biodegradable materials.
It’s now widely accepted that toxic chemicals from plastics can leach into your food and drink, but the same concern now applies to what you put on your skin.
Many brands have turned to recycled plastics to develop more sustainable activewear, often with good intentions in reducing waste - but the idea of wrapping our bodies in plastic has never felt right, and the emerging science is beginning to validate this.
It's a cruel irony that in the pursuit of being healthy and detoxifying our bodies through exercise, we may instead be increasing our toxic load by wearing materials that do the opposite.
Absorption of Forever Chemicals Through Skin
Your skin is your largest organ, and while it is designed to protect, it is not a perfect barrier. Think about how skincare products, topical pain relief, or even nicotine patches work. They penetrate the skin and are absorbed into the body.
Scientific evidence now shows that it's our sweat, especially its oily components, that can draw out lipophilic (fat-attracted) chemicals like BPA and phthalates from synthetic fabrics. Once released, these substances can be absorbed into the bloodstream.
The combination of plastic fabrics worn close to the body, plus friction, heat, and sweat, creates the perfect conditions for chemicals to leach out and disrupt the body’s natural balance.
This is exactly what happens during high-intensity exercise, and once absorbed, PFAS, BPA, and phthalates can interfere with hormone signalling, bind to cellular receptors, and alter hormone production.
Research in both humans and animals has linked these chemicals to negative metabolic effects, and certain PFAS have even been associated with an increased risk of cancer.
Forever Chemicals Overview
PFAS linked to hormone disruption, cancer risk
BPA an endocrine disruptor often found in plastic coatings
Phthalates used to soften plastics, known to interfere with hormones
And then there is the microplastic problem.
Synthetic Clothing Releases Microplastics
Every time synthetic clothing is worn and washed, it sheds tiny fragments called microplastics.
These particles travel through air, evade water treatment systems, and settle in oceans, soil, and eventually our food chains.
A single laundry load of synthetic garments can release hundreds of thousands of microfibres into the water, with dryers also venting out these plastics into the air, not to mention how friction during wear sheds fibres into the air and dust.
How do microplastics affect human health?
Terrifying statistics are coming out on how much of the world is now polluted with microplastics.
Studies have detected microplastics in human lungs, placenta, and bloodstream. In one study published in 2022, nearly four in five participants had detectable microplastics in blood.
Once plastic reaches your organs, there’s no natural way for it to escape.
Particles can lodge in tissues, generate inflammation and oxidative stress, and act as carriers that concentrate and transport other toxic chemicals into the body.
So what can we do to help prevent this toxic build-up in our bodies? And what does this mean for synthetic activewear?
How to Choose Safer Activewear
1. Check the fabric composition and choose natural fibres wherever possible
Opt for organic cotton, bamboo, hemp, merino wool, natural rubber, TENCEL™, and bio‑based elastanes wherever you can. These elastanes aren’t perfect, but they’re a better option than conventional synthetics.
It’s extremely difficult to recreate the compression and strength of synthetic fibres in activewear, which is why small amounts of elastane are often still used.
2. Check certifications
Look for OEKO-TEX® or GOTS labels to ensure garments have been tested for harmful substances.
3. Avoid coatings and finishings
Steer clear of terms like “anti-odour,” “stain-resistant,” or “moisture-wicking” unless they come with clear, non-toxic certifications or natural fabrics (like the ones mentioned above).
4. Wash consciously
Use cold water. And if you want to level up, you could consider buying a microfibre-filtering laundry bag to reduce plastic shedding.
5. Dry smarter
Air dry whenever possible. If using a dryer, make sure it vents outdoors to avoid breathing in the microplastics that get expelled into the air from the vent.
6. Retire worn-out gear
Old synthetic fabrics shed the most microplastics and can leach even more chemicals. When items reach the end of their life, check if they can be recycled through brand take back schemes or textile recycling programs. Choosing natural fibre replacements will support biodegradation which is kind to the planet.
Final Thoughts
What we are exposed to every day matters most. Unfortunately, the way our modern world works means there is a lot that is out of our control. But by asking the right questions and learning about risks, we can arm ourselves with knowledge to demand safer products and higher industry standards.
Read our article on simple, practical changes you can control to reduce your toxic load in other areas of life. Many of these are small, actionable steps you can implement immediately to ease the burden on both your body and the planet.
Every small choice adds up, and each change you make is an investment in your health, your future, and a cleaner world.
References
Carrington, D. (2022, March 24). Microplastics found in human blood for first time. The Guardian. https://www.theguardian.com/
Center for Environmental Health. (2022, October 12). New testing shows high levels of BPA in sports bras and athletic shirts. https://ceh.org/
European Environment Agency. (2022). Microplastics from textiles: Towards a circular economy for textiles in Europe. https://www.eea.europa.eu/
Li, H.-L., Ma, W.-L., Liu, L.-Y., et al. (2019). Phthalates in infant cotton clothing: Occurrence and implications for human exposure. Science of the Total Environment, 683, 109–115. https://doi.org/10.1016/j.scitotenv.2019.05.132
Abdallah, M. A.-E., et al. (2023). Chemical transfer from synthetic textiles into human skin under realistic conditions. Journal of Hazardous Materials, 443, 130155. https://doi.org/10.1016/j.jhazmat.2022.130155
Centers for Disease Control and Prevention. National biomonitoring data on PFAS in human blood, United States.
International Agency for Research on Cancer. Carcinogenicity classifications for PFOA and PFOS.
Grandjean, P., et al. Studies linking PFAS exposure with reduced vaccine antibody responses in children.
European Chemicals Agency. Proposals and assessments regarding PFAS restrictions in consumer products.
Leslie, H. A., et al. Microplastics detected in human blood, Environment International, 2022.
Studies reporting microplastics in human lung tissue and placenta in clinical samples.
International Union for Conservation of Nature. Primary microplastics in the oceans and textile fibre contributions.
Napper, I. E., and Thompson, R. C. Quantification of microfibre release during domestic laundering.
Epidemiologic and toxicologic literature on BPA and phthalate exposure, endocrine and reproductive endpoints.
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