What is lyocell?

What is lyocell?

Lyocell is a semi-synthetic fiber made from wood pulp dissolved in NMMO (N-methylmorpholine N-oxide) — a non-toxic solvent — and extruded into fiber. More than 99% of the solvent is recovered and reused in a closed loop. The fiber is soft, breathable, and biodegradable. Tencel is the brand name for lyocell made by Lenzing AG; it is the most widely sold form of lyocell.

Is Tencel the same as lyocell?

Tencel is a brand name for lyocell produced by Lenzing AG. The fiber itself is lyocell regardless of brand. Lenzing commercialized the closed-loop production process and Tencel became the most recognized name for it. Other manufacturers also produce lyocell, but when a brand says "Tencel" they are specifically using Lenzing's fiber, which comes with traceability and environmental standards attached.

Is lyocell a natural fiber?

No. Lyocell is semi-synthetic. It starts from a natural and renewable source — wood pulp — and uses a much cleaner production process than viscose or modal. But the fiber itself is manufactured through a chemical process and does not occur in nature. Natural fibers such as cotton, linen, wool, and silk require no chemical conversion. Lyocell is the cleanest of the cellulosic semi-synthetics, but it is still a semi-synthetic fiber.

How is lyocell different from viscose and modal?

All three are regenerated cellulose fibers made from wood pulp. The key difference is in how they are made. Viscose uses carbon disulfide — a toxic chemical that can harm workers and the environment if mishandled. Modal uses a modified wet spinning process with better results than viscose but still relies on chemicals that require careful handling. Lyocell uses NMMO, a non-toxic solvent, in a closed-loop process that captures and reuses over 99% of it. In terms of environmental impact: lyocell is the cleanest, followed by modal, then viscose.

Is lyocell breathable?

Yes. Lyocell absorbs moisture and releases it efficiently, keeping the fabric from feeling damp against skin. It is more breathable than polyester and comparable to cotton for moisture management. The fiber naturally inhibits bacterial growth due to its low moisture retention, which is why it is used in bedding and activewear.

Is lyocell sustainable?

Compared to other semi-synthetic and synthetic fibers, yes. The wood pulp typically comes from FSC-certified forests, the NMMO solvent is non-toxic and almost fully recovered, and the finished fiber is biodegradable. It uses significantly less water than cotton and does not require pesticides. No fiber is without environmental cost, but lyocell has a lower impact than viscose, modal, polyester, or conventionally grown cotton.

Does lyocell wrinkle?

Lyocell wrinkles more easily than polyester and similarly to cotton. It has a slightly better drape than cotton, which means wrinkles tend to fall out with wear. Washing in cold water and removing garments promptly from the dryer reduces wrinkling. Most lyocell garments can be lightly steamed.

Is lyocell toxic?

No. Lyocell is one of the least toxic fibers in production. It uses NMMO (N-methylmorpholine N-oxide), a non-toxic solvent, in a closed-loop system that captures over 99% of it. This contrasts with viscose, which uses carbon disulfide — a genuinely toxic chemical. The finished lyocell fiber is also free from harmful residues and is biodegradable. Some lyocell is finished with chemical treatments (wrinkle resistance, water repellency) that add separate considerations, but the base fiber production is considered clean.

Why does The Plain Thread list lyocell but not viscose or modal?

The Plain Thread focuses on natural fibers, but makes a limited exception for lyocell given its fundamentally different and cleaner production process. Viscose uses toxic carbon disulfide with limited solvent recovery. Modal improves on that but still uses open chemical processes. Lyocell uses a non-toxic, closed-loop solvent system — a meaningful difference in environmental impact. We note clearly on brand listings when lyocell is included, and we do not treat it as equivalent to cotton, linen, wool, hemp, or silk.

Every brand in The Plain Thread directory uses natural fibers: cotton, linen, wool, hemp, silk, alpaca, and cashmere. Some brands also use lyocell alongside natural fibers.