What is polyester? What it is made of, and why it is plastic

Updated · 6 sources · How we research

PlasticSynthetic polymer

Fiber Facts

Polyester

Type
Synthetic (plastic)
Made from
Petroleum-derived chemicals (ethylene glycol and terephthalic acid) polymerized into PET
Share of world fiber (2024)
59%
Made from fossil fuels
88% of polyester
US legal definition
A long-chain synthetic polymer, at least 85% an ester of a substituted aromatic carboxylic acid
Sheds in one 6 kg wash
About 496,000 fibers

Every figure is sourced at the foot of the page.

What polyester is made of

Polyester starts as oil and gas. Two petrochemicals, ethylene glycol and terephthalic acid, are reacted into polyethylene terephthalate (PET), the same plastic as a drink bottle. US law defines polyester as a long-chain synthetic polymer that is at least 85% an ester of a substituted aromatic carboxylic acid. In 2024 polyester was 59% of all fiber produced worldwide, and 88% of it was made from fossil fuels.

How polyester is made

The PET is melted and pushed through tiny holes to form continuous filaments, which are stretched, cooled and either kept as filament or cut and spun into yarn. Most PET is made with an antimony catalyst, and some of that antimony stays in the finished fiber.

What polyester sheds

Polyester sheds plastic. One 6 kg wash of polyester released about 496,000 microfibers. Wearing it sheds too: up to 400 fibers per gram of fabric in 20 minutes of normal activity.

How to spot polyester on a label

Look for polyester, PET, recycled polyester or rPET. “Microfiber,” “performance,” “moisture-wicking” and “quick-dry” usually mean polyester or another synthetic. The fiber content label is required by law; the marketing words are not.

Frequently asked questions

Is polyester plastic?

Yes. Polyester is a synthetic polymer, and most polyester fiber is PET, the same plastic used to make drink bottles. It is plastic in every sense: made from petrochemicals, melted, extruded and spun.

Is recycled polyester still plastic?

Yes. Recycled polyester (rPET) is the same polymer, usually made from melted bottles. It is still plastic against your skin and still sheds plastic microfibers in the wash.

Is microfiber polyester?

Usually. Microfiber is a description of a very fine fiber, not a fiber type, and most microfiber fabric is polyester or a polyester-nylon blend. Check the fiber content on the label.

Sources

  1. Textile Exchange (2025), Materials Market Report 2025. textileexchange.org
  2. US Federal Trade Commission, Textile Fiber Products Identification Act rules, 16 CFR §303.7, Generic names and definitions for manufactured fibers. ecfr.gov
  3. Napper IE, Thompson RC (2016), Release of synthetic microplastic plastic fibres from domestic washing machines, Marine Pollution Bulletin 112. doi.org
  4. De Falco F et al. (2020), Microfiber Release to Water, Via Laundering, and to Air, via Everyday Use, Environmental Science & Technology 54(6). pubmed.ncbi.nlm.nih.gov
  5. Biver M, Turner A, Filella M (2021), Antimony release from polyester textiles by artificial sweat solutions, Regulatory Toxicology and Pharmacology 119:104824. doi.org
  6. IARC Monographs Volume 131 (2023), Cobalt, antimony compounds, and weapons-grade tungsten alloy. monographs.iarc.who.int