# The Polyester Problem > A guide to textile fibers: what polyester and other synthetics are, what the research says they do to you and the planet, and the natural fibers and brands that replace them. Every page opens with a short answer and lists its sources. Full text of every answer page: https://polyesterproblem.org/llms-full.txt ## Is polyester bad for me - [Is polyester bad for you? What the research shows](https://polyesterproblem.org/is-polyester-bad-for-you/): Polyester is plastic, and wearing it has documented costs. The fiber carries antimony, a catalyst residue that moves into sweat in lab tests and is classified as probably carcinogenic. Water- and stain-repellent finishes often use PFAS, and PFOA is a known human carcinogen. Polyester also holds odor and sheds plastic microfibers. ## Fiber vs fiber - [Nylon vs polyester: both are plastic, and how they differ](https://polyesterproblem.org/nylon-vs-polyester/): Nylon and polyester are both plastic. Nylon is a synthetic polyamide made from petrochemicals such as caprolactam or adipic acid; polyester is mostly PET. Both are melted and extruded into fiber, both shed microfibers in the wash, and both are colored with disperse dyes, the most common cause of textile skin allergy. Neither is a natural fiber. ## Cotton: kinds, labels and costs - [Is cotton sustainable? Water, pesticides and chemical finishes](https://polyesterproblem.org/is-cotton-sustainable/): Cotton is natural and biodegradable, but conventional cotton has real costs. It takes about a tenth of the world's insecticides on 2.3% of its farmland, 44% of cotton land is irrigated, and finishes such as no-iron resins and water repellents can add formaldehyde and PFAS. Rain-fed, organic, GOTS-certified cotton avoids most of that. - [Organic cotton vs regular cotton: pesticides, GMOs and labels](https://polyesterproblem.org/organic-cotton-vs-regular-cotton/): Organic cotton is grown without genetically modified seed and without synthetic pesticides and fertilizers, except a short list of approved substances. Most regular cotton is GM: 79% of the world's cotton area in 2019. Organic was only 2.9% of new cotton in 2023/24, most of it from India, and fraud has been found. Look for GOTS certification on the finished product. - [Pima, Supima and Egyptian cotton: what the names mean](https://polyesterproblem.org/pima-supima-egyptian-cotton/): Pima is extra-long-staple cotton, Gossypium barbadense, grown in the US Southwest; it's about 3% of the US crop. Supima is a trademark only products made of 100% US Pima can carry. Egyptian cotton is cotton grown in Egypt, and only about 10% of Egypt's 2024/25 crop was extra-long staple. All three are natural cotton. ## Chemicals and plastic in clothing - [The chemical finishes on your clothes, and what washing removes](https://polyesterproblem.org/chemical-finishes-on-clothing/): Many new clothes leave the mill with a chemical finish padded on and baked in: resins that stop wrinkles, fluorinated or silicone coatings that repel water and stains, antimicrobials that block odor, and flame retardants in some children's sleepwear. Washing new clothes removes loose residues such as free formaldehyde, but durable finishes are built to survive dozens of washes. - [OEKO-TEX and GOTS: what the certifications test for](https://polyesterproblem.org/oeko-tex-gots-certification/): OEKO-TEX STANDARD 100 tests a finished textile for harmful substances such as formaldehyde, PFAS and allergenic dyes. It certifies any fiber, polyester included, and says nothing about how the fiber was grown. GOTS certifies organic textiles: at least 70% certified organic fiber, 95% for the organic label, no virgin polyester, and no formaldehyde, PFAS or GM inputs. - [PFAS in clothing: which clothes have forever chemicals](https://polyesterproblem.org/pfas-in-clothing/): PFAS are a class of thousands of fluorinated chemicals that barely break down, which is why they're called forever chemicals. In clothing they come mostly from water-, stain- and oil-repellent finishes on rain jackets, outdoor gear, stain-resistant school uniforms and some period underwear. Polyester itself isn't a PFAS. The surest way to avoid them is to skip clothes sold as water- or stain-resistant. ## Fiber profiles - [Cotton](https://polyesterproblem.org/fibers/cotton/): Cotton is a natural fiber that grows around the seeds of the cotton plant. Each fiber is a single plant cell, more than 90% cellulose. It's picked, ginned to pull the lint off the seed, then carded and spun into yarn. Cotton isn't plastic, and it made up 19% of the fiber produced worldwide in 2024. - [Linen](https://polyesterproblem.org/fibers/linen/): Linen is a natural fiber made from the stem of the flax plant, Linum usitatissimum. The long fibers inside the stalk are loosened in the field, separated, combed and spun into yarn. Linen is grown, not polymerized: it contains no plastic and sheds no plastic microfibers. Flax is about 0.3% of the fiber the world produces. - [Modal](https://polyesterproblem.org/fibers/modal/): Modal is a type of rayon: wood pulp dissolved through the viscose process, which uses carbon disulfide, and spun into a fiber engineered to stay strong when wet. It is not plastic and not a natural fiber; it is regenerated cellulose. The best-known modal, Lenzing's TENCEL Modal, is made mainly from beech wood. - [Polyester](https://polyesterproblem.org/fibers/polyester/): Polyester is plastic. Most polyester fiber is polyethylene terephthalate (PET), the polymer in drink bottles, melted and spun into thread. It makes up 59% of the fiber the world produces, and 88% of that is made from fossil fuels. Every wash and every wear sheds plastic microfibers. - [Rayon](https://polyesterproblem.org/fibers/rayon/): No. Rayon is a manufactured fiber made from plant cellulose, usually wood, that is dissolved with chemicals and spun back into fiber. US law defines it as regenerated cellulose. It is not plastic, but it is not grown as fiber either. Viscose, modal and lyocell are all kinds of rayon, and "bamboo" fabric is almost always rayon. - [Viscose](https://polyesterproblem.org/fibers/viscose/): Viscose is a fiber made from wood pulp. The cellulose is dissolved with sodium hydroxide and carbon disulfide, then pushed through a spinneret into an acid bath, where it sets into filaments. It is not plastic and it is not a natural fiber: US law calls it rayon, a manufactured fiber of regenerated cellulose. The carbon disulfide has harmed the workers who make it. ## About - [Editorial standards](https://polyesterproblem.org/about/editorial-standards/) - [Sources](https://polyesterproblem.org/sources/)