Recycled sportswear: why it's not healthier for you or the planet

Recycled sportswear sounds like the answer to fast fashion: better for the environment and a good feeling for you as a consumer. Brands emphasize that their leggings, tops, and running shirts are made from "recycled plastic bottles" or "ocean waste." But behind that green promise lies a complex story. Scientific studies show that recycled plastic sportswear is often not healthier for you and that the planet is barely helped by it. In fact, in some cases, it can even be more harmful.

Microplastics: recycled polyester releases more fibers

The biggest problem with synthetic clothing is the release of microplastics. During wear and especially during washing, millions of microscopic fibers are released. These fibers end up in rivers, oceans, and ultimately on our plates via fish, sea salt, and even drinking water. And here's the surprise: recycled polyester performs worse than virgin polyester.

A study in Environmental Research (2024) shows that recycled polyester releases more microplastics than virgin polyester: an average of 1,193 fibers versus 908 under the same test conditions.^[1] Researchers estimate that one wash cycle can release up to 700,000 fibers from synthetic clothing. This makes textiles the largest source of primary microplastics in the oceans.^[2]

Another study shows that recycled polyester can release up to 2.3 times more fibers than new polyester, because the fiber structure becomes more brittle due to the mechanical and chemical recycling process.^[3] This means that the "green" alternative actually causes more pollution.

What does this mean for you? Microplastics are inhaled or ingested. Studies have now found them in human lungs, blood, placentas, and even in testicles.^[4] There is evidence that they cause inflammatory reactions, increase oxidative stress, and can disrupt hormone systems.^[5]

Harmful chemicals do not disappear through recycling

Polyester is not just a neutral plastic thread. During production and use, chemicals are added: dyes, antimony (catalyst), plasticizers, flame retardants, and coatings. Many of these substances have a proven or suspected endocrine-disrupting effect. The problem? These chemicals remain present, even after recycling.

A study in Journal of Environmental Science and Health (2025) shows that recycled polyester can release toxic substances into artificial sweat and can be absorbed through the skin.^[6] Antimony, used in polyester production, has been shown to be released from clothing upon contact with sweat. This metal is toxic and can, with chronic exposure, affect the skin, liver, and lungs.^[7]

Research also shows that phthalates – endocrine-disrupting plasticizers – are often found in recycled plastics because they are not removed during the recycling process.^[8] These substances accumulate in your body and can negatively affect fertility.

What does this mean for you? When exercising, your skin is warm and moist – the perfect conditions for chemical migration. This way, your body can be exposed for a long time to substances that affect your hormone balance and fertility. Recent research confirmed that microplastics from textiles release toxic chemicals when they come into contact with sweat, increasing absorption through the skin.^[9]

Recycling = chemicals keep circulating

A large part of the fashion industry promotes "circular clothing" as the solution. But in reality, recycling often ensures that harmful substances re-enter the chain. According to an analysis, PFAS, dyes, and other chemicals remain present in recycled textiles and are reused in new garments. In this way, toxins move through the chain instead of disappearing.^[10]

Extensive research in Chemosphere showed that recycling processes do not effectively remove endocrine-disrupting chemicals. Instead of a clean solution, recycling often becomes a way to keep pollution circulating longer.^[11]

What does this mean for the planet? Instead of a clean solution, recycling often becomes a way to keep pollution circulating longer. The substances do not disappear but simply change form. Scientists call this phenomenon "chemical recycling" – recycling the problems instead of the solutions.

The promised CO₂ savings are relatively small

Brands claim that recycled polyester results in up to 60% less CO₂ emissions compared to virgin polyester. That is true in lifecycle analyses, but the picture is less rosy than it seems. The production of virgin polyester remains dominant – recycled polyester still represents a small percentage of the total market.

By using PET bottles for clothing, these bottles are removed from the bottle-to-bottle recycling process. The plastic can then no longer be used for food packaging, which actually requires more virgin plastic. An in-depth article in Wired describes how Repreve fibers (the best-known recycled polyester fibers) do not reduce dependence on plastic but rather perpetuate it.^[12]

Moreover, research shows that the actual CO₂ savings are smaller than often claimed, especially when transport and reprocessing are included in the calculation.^[13]

Little changes for the planet:

• Synthetic fibers do not decompose and remain in the environment for hundreds of years.
• Washing and wearing recycled sportswear still contributes massively to microplastic pollution.
• The idea of "ocean waste" sounds nice, but only a small part of ocean plastic is suitable for clothing. The majority still comes from PET bottles and industrial waste, not from beaches or the sea.
• Studies show that less than 1% of the plastic in oceans is actually recycled into textiles – the rest continues to pollute.^[14]

Recycled versus organic cotton: the health impact

When you compare recycled polyester with organic cotton, the difference for your health becomes truly clear. Organic cotton is grown without pesticides, processed without aggressive chemicals, and does not release microplastics. It is naturally breathable, hypoallergenic, and free of endocrine disruptors.^[15]

A study comparing skin irritation between synthetic and natural fibers found that organic cotton caused significantly fewer allergic reactions and was better tolerated by people with eczema and sensitive skin.^[16] For sportswear that sits against your skin for a long time, this is no small detail.

Conclusion

Recycled plastic sportswear is NOT a miracle cure. It may give you a green feeling, but the scientific facts tell a different story:

• It releases more microplastics than new polyester.
• Harmful chemicals remain present and migrate to your skin.
• Recycling circulates toxins instead of removing them.
• The CO₂ savings are marginal compared to the scale of the problem.
• It removes valuable raw materials from more effective recycling processes.

For your health and the planet, recycled plastic is therefore not healthier.

The real solutions

Choose natural fibers

Organic cotton, hemp, and merino wool are breathable, biodegradable, and free of microplastics. At NOHI NATURAL, we work exclusively with GOTS-certified organic cotton. Check out our sportswear collection.

Buy less, but better

Quality over quantity. One well-made cotton legging that lasts for years is better than five cheap recycled polyester ones that wear out quickly.

Wash consciously

Wash less often, at a lower temperature, and use a microfiber filter or wash bag if you do own synthetic clothing. But realize: this reduces the problem, it doesn't solve it.

Ask for transparency

Ask brands for certifications such as GOTS and OEKO-TEX 100. Without independent verification, "green" claims are often just marketing.