Reshaping what it means to be a responsible brand

The fashion industry has long debated sustainability in terms of water use, carbon footprints, and supply chain transparency. But a bigger question looms, demanding attention from every designer, product developer, and sourcing director making fiber decisions today.

That question: what to do about the microplastics problem? Microplastics, tiny plastic particles less than 5mm in size, have permeated every aspect of our lives.^1,2 They’re no longer just an environmental talking point, but a key consideration for every consumer-focused brand.

The dangers associated with synthetic fibers

The data is difficult to ignore: synthetic textiles are the single largest source of primary microplastics entering the world’s oceans, responsible for an estimated 35% of total oceanic microplastic release.³ Every polyester shirt, nylon activewear piece, or blended knit your brand produces sheds microfibers during routine wear and washing.^{1, 2}

What’s more, polyester microfibers do not biodegrade.⁴ They slip through wastewater treatment infrastructure, travel through freshwater systems, and ultimately accumulate in the ocean, where they remain for decades.^{4, 5} Right now, there is no downstream fix. The decision lives upstream, in your textile choice.

From ocean floor to human tissue: The stakes are escalating

Microplastics as an environmental story are now becoming a human health story, a distinction that matters enormously for brands.

Microplastics have been detected in air, soil, and drinking water.⁵ More significantly for consumer-facing brands, they have been identified in human lungs, blood, the placenta, and the brain.⁷ A 2025 study of 40 human brain samples found that microplastic concentrations measured in 2024 were roughly 50% higher than those recorded in 2016 — a preliminary finding that points to a sharp upward trend. More complex studies with larger cohorts are need to fully understand human health effects.

The cardiovascular findings are equally striking. Studies conducted in both China and Italy found microplastics present in human arterial tissue, including the carotid arteries, coronary arteries, and aorta arteries.^{8, 9} Researchers are careful to note these findings do not establish direct causation, and broader studies are needed.^{8, 9} But the trajectory of this science is unmistakable. Brands that have built product lines on synthetic fibers should ask now, not later, how they want to be positioned as public awareness grows.

The natural answer is cotton

The good news for product teams is that a high-performing, scalable alternative already exists. Cotton is composed of cellulose,⁶ a natural plant compound that integrates seamlessly into Earth’s biological cycles.^{10, 11} In practical terms, that means cotton fibers break down. Polyester fibers do not.

The contrast is stark in the research. In freshwater environments, cotton has demonstrated biodegradation rates by as much as 77% within a month — while polyester showed no measurable breakdown over the same period.¹ Even cotton treated with common textile dyes and finishes degrades at rates comparable to natural organic matter like oak leaves within 102 days under realistic environmental conditions.¹²

For a sourcing director, this is not an abstract environmental metric. It is the difference between a product that exits the ecosystem gracefully and one that accumulates in waterways, in soil, and increasingly, in our own bodies.

As regulatory scrutiny of microplastic pollution intensifies globally and consumer awareness grows, the fiber composition tag inside a garment is becoming a brand statement — whether a manufacturer intends it or not. Choosing cotton allows you to meet the moment with smart, sustainable textile choices that consumers will increasingly demand. See why cotton is the microplastics-free, circular choice at CottonWorks.com/microplastics.

© 2026 Cotton Incorporated. Service Mark / Trademark of Cotton Incorporated. AMERICA’S COTTON PRODUCERS AND IMPORTERS.

References

1. Marielis C. Zambrano et al. (2020). Aerobic Biodegradation in Freshwater and Marine Environments of Textile Microfibers Generated in Clothes Laundering: Effects of Cellulose and  Polyester-Based Microfibers on the Microbiome. Marine Pollution Bulletin 151: p. 110826, https://doi.org/10.1016/j.marpolbul.2019.110826 
2. Marielis C. Zambrano et al. (2019). Microfibers Generated from the Laundering of Cotton, Rayon and Polyester Based Fabrics and Their Aquatic Biodegradation. Marine Pollution  Bulletin 142: pp. 394-407, https://doi.org/10.1016/j.marpolbul.2019.02.062.
3. International Union for Conservation of Nature (IUCN). (2017). Primary microplastics in the oceans: A global evaluation of sources (IUCN Issues Brief No. 2017-002).  Gland, Switzerland: IUCN. Retrieved from https://portals.iucn.org/library/node/46622
4. Marielis C. Zambrano et al. (2020). Aerobic Biodegradation in Freshwater and Marine Environments of Textile Microfibers Generated in Clothes Laundering: Effects of Cellulose and Polyester-Based Microfibers on the Microbiome. Marine Pollution Bulletin 151: p. 110826, https://doi.org/10.1016/j.marpolbul.2019.110826
5. U.S. Environmental Protection Agency. (2020). What You Should Know About Microfiber Pollution.https://www.epa.gov/sites/default/files/2020-08/documents/article_2_microfibers_formatted.pdf
6. Wakelyn, P.J. (2006). Cotton Fiber Chemistry and Technology (1st ed.). CRC Press. Chapter 3. https://doi.org/10.1201/9781420045888)
7.  Nihart, A.J., Garcia, M.A., El Hayek, E. et al. Bioaccumulation of microplastics in decedent human brains. Nat Med 31, 1114–1119 (2025). https://doi.org/10.1038/s41591-024-03453-1
8. Liu S, Wang C, Yang Y, Du Z, Li L, Zhang M, Ni S, Yue Z, Yang K, Wang Y, Li X, Yang Y, Qin Y, Li J, Yang Y, Zhang M. (2024). Microplastics in three types of human arteries detected by pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS). Journal of Hazardous Materials. DOI: 10.1016/j.jhazmat.2024.133855
9. Marfella, R., Prattichizzo, F., Sardu, C., Fulgenzi, G., Graciotti, L., Spadoni, T., D’Onofrio, N., & Paolisso, G. (2024). Microplastics and nanoplastics in atheromas and cardiovascular events. New England Journal of Medicine, 390(10), 900–910. https://doi.org/10.1056/NEJMoa2309822
10.  Ho, N. W. Y., Ladisch, M. R., Sedlak, M., Mosier, N., & Casey, E. (2011). Biofuels from Cellulosic Feedstocks. Comprehensive Biotechnology, Second Edition, 3, 51–62. https://doi.org/10.1016/B978-0-08-088504-9.00155-0
11. Thomas Heinze (2015). Cellulose: Structure and Properties. Cellulose Chemistry and Properties: Fibers, Nanocelluloses and Advanced Materials. pp 1-52.  https://link.springer.com/chapter/10.1007/12_2015_319
12.  Marielis C. Zambrano et al. (2021). Impact of Dyes and Finishes on the Aquatic Biodegradability of Cotton Textile Fibers and Microfibers Released on Laundering Clothes: Correlations between Enzyme Adsorption and Activity and Biodegradation Rates. Marine Pollution Bulletin 165: p. 112030. https://doi.org/10.1016/j.marpolbul.2021.112030.