Study shows cotton and wool shed more microfibers than polyester, and they’re not as “natural” as you’d think.

The Clothes We Think Are Safe

When most people think about microfiber pollution, they picture synthetic fabrics like polyester and nylon. Natural fabrics like cotton and wool feel like the “safe” choice. They are, after all, biodegradable, renewable, and often marketed as an eco-friendly alternative. But new research says that assumption is misleading.

What's Wrong with My Cotton Shirt?

A study published in Environmental Science & Technology analyzed dozens of previous experiments on microfiber shedding from different fabrics. The results were surprising: cotton clothes actually shed more microfibers than polyester when washed. The reason for this lies in the way natural fibers are spun. Cotton and wool are made of short staple fibers twisted into yarn, which makes them more likely to break off in the wash. On the other hand, polyester is spun from longer filaments that hold together more tightly, so less tends to shed.

Why Isn’t Cotton OK in The Environment?

At first glance, it might sound like good news that cotton breaks down faster than plastic. After all, doesn’t cotton just come from plants? However, the truth is more complicated. Once natural fibers are released, they do not enter the environment as pure cotton or wool. They carry the dyes, coatings, and chemical treatments that were added to the fabric during production.

Out in the world, these fibers do not just disappear. They can linger in soils and waterways, collecting pollutants on their surfaces and eventually finding their way into the food chain. Sustainability consultant Philippa Grogan of strategy consultancy Eco-Age explains: “The amount of treatments and coatings used on natural fibres can also make them behave more like microplastics... If natural fibres have been coated in something like a durable water repellent coating, they will behave like a microplastic, which affects their biodegradability.”

Should You Be Concerned?

Although we do not yet fully understand the health effects of consuming microplastics, research has already linked them to inflammation, hormone disruption, and the potential to carry toxic chemicals into the body. These concerns are especially relevant when microplastics break down into even smaller particles, called nanoplastics, which can enter organs and tissues more easily.

So, the next time you pull on a cotton t-shirt or toss your favorite sweater in the wash, it is worth remembering that what feels natural is not always harmless once it leaves your home. Those fibers that shed may look invisible, but they carry dyes and coatings that linger in the environment long after you are done wearing them. Choosing natural fabrics is not a free pass on microfiber pollution. It is a reminder that every wash cycle connects our closets to rivers, soil, and even our food. The more we understand this hidden impact, the closer we get to finding real solutions.

How You Can Help

Studies have found that the largest source of microplastic pollution is textile shed, with up to 35% of all microplastic pollution in our environment coming from everyday clothes. CLEANR’s Premium Microplastic Filter for washing machines captures 90%+ of microplastics from the largest source of microplastic pollution, preventing them from entering our ecosystems.

Learn more

About CLEANR

CLEANR builds best-in-class microplastic filters for washing machines that effortlessly remove the largest source of microplastics into the environment. Its technology, VORTX, represents a breakthrough in filtration, with a patented design that is inspired by nature and proven to outperform conventional filtration technologies by over 300%. The company is building a platform filter technology that enables product manufacturers and business customers to materially reduce their microplastic emissions from impacted in-bound and out-bound fluid streams, including residential and commercial washing machine wastewater, in-home water systems, wastewater treatment, textile manufacturing effluents, industrial wastewater, and other sources. www.cleanr.life

Sources:

Allen, E., Henninger, C. E., Garforth, A., & Asuquo, E. (2024). Microfiber pollution: A systematic literature review to overcome the complexities in knit design to create solutions for knit fabrics. Environmental Science & Technology, 58(9), 4031–4045. https://doi.org/10.1021/acs.est.3c05955
Webb, B. (2023). Why is fashion still ignoring microfibres? Forum for the Future. https://www.forumforthefuture.org/why-is-fashion-still-ignoring-microfibres
Ullah, S., Ahmad, S., Guo, X., Ullah, S., Ullah, S., Nabi, G., & Wanghe, K. (2023, January 16). A review of the endocrine disrupting effects of micro and nano plastic and their associated chemicals in mammals. Frontiers in Endocrinology, 13, 1084236. https://doi.org/10.3389/fendo.2022.1084236

More Microplastics News