Is rayon a natural fiber? What rayon is and how to read the label

What rayon is

Rayon is plant cellulose, almost always from wood, that has been dissolved and spun back into fiber. US law defines it as “a manufactured fiber composed of regenerated cellulose.” That puts it in a category of its own: it is not grown as fiber like cotton or linen, and it is not a synthetic polymer like polyester.

Is rayon a natural fiber?

No. Rayon begins with a natural material, but the fiber itself is made in a factory. The plant is pulped, the cellulose is dissolved, and the solution is forced through spinnerets to form new filaments. Natural fibers are harvested as fibers: cotton from the seed boll, linen from the flax stem, wool from the sheep.

Rayon is not plastic either. US law defines polyester, nylon and acrylic as “long chain synthetic polymers” and rayon as regenerated cellulose, and EU guidance says viscose and lyocell are not plastic.

The kinds of rayon

Man-made cellulosic fibers were about 6% of the world’s fiber in 2024, 8.4 million tonnes:

• Viscose: 80% of the category. Made by dissolving cellulose with sodium hydroxide and carbon disulfide. See what viscose is.
• Lyocell: 5%. Dissolved in an organic solvent instead of carbon disulfide; US law allows the name lyocell for it. TENCEL is a brand of lyocell and modal.
• Modal: about 3%. A viscose-process fiber engineered to stay strong when wet. See what modal is.
• Cupro: 0.2%.

The FTC lets US labels use the international names viscose and modal as well as rayon.

Rayon, polyester and cotton

	Polyester	Rayon	Cotton
What it is	Plastic (PET), mostly from fossil fuels	Plant cellulose, dissolved and respun	Seed fiber, grown and spun
US legal category	Long chain synthetic polymer	Regenerated cellulose	Natural fiber
Is it plastic?	Yes	No	No
Yarn biodegradation in lake water	Did not appreciably degrade	More than 70%	More than 70%
Share of world fiber, 2024	59%	About 6% (all cellulosics)	19%

“Bamboo” fabric is rayon

Soft “bamboo” sheets and shirts are rayon made from bamboo pulp. The FTC says most bamboo textiles, if not all, are rayon, and that the honest label is “rayon made from bamboo.” In 2022 Kohl’s paid $2.5 million and Walmart $3 million in civil penalties for marketing rayon as bamboo. The FTC said converting bamboo into rayon requires toxic chemicals and produces hazardous pollutants.

How to read a rayon label

Look for rayon, viscose, modal, lyocell or cupro: all are regenerated cellulose. “Bamboo” on its own is not a fiber name. Rayon is often blended with polyester or spandex, and a US label must list each fiber’s percentage, so check the whole line before deciding a garment is plastic-free.