What Is Lyocell (Tencel)?

How is lyocell made?

Lyocell is made by dissolving cellulose pulp directly in an organic solvent, spinning the solution into filaments and recovering the solvent, with no chemical derivative of the cellulose formed along the way. The solvent named in both the US rule-making and a Courtaulds patent filing is N-methylmorpholine N-oxide (NMMO) mixed with water.

1. Pulp. Lenzing, which sells lyocell as TENCEL™, says it uses wood from controlled or certified sources meeting FSC or PEFC standards.
2. Dissolving. The pulp is dissolved in the NMMO and water mixture to form a spinning solution.
3. Spinning. The solution is spun into filaments, and the cellulose is precipitated back out of solution as fibre.
4. Washing and cutting. The filaments are washed and dried; according to Lenzing, they are cut into staple fibre either before or after this stage.
5. Solvent recovery. Lenzing says more than 99.8% of its solvent is recovered and fed back into the process.

That process is what gives lyocell its legal identity. US rules define it as a kind of rayon made from cellulose precipitated from an organic solution, with no substitution and no chemical intermediates. EU rules define it as a regenerated cellulose fibre spun from an organic solvent “without formation of derivatives”.

Who developed lyocell?

Lyocell got its name through an application by Courtaulds. Courtaulds Fibers, Inc. asked the Federal Trade Commission (FTC) for a new fibre name on 27 January 1992. The FTC decided in 1996 that lyocell was a subclass of rayon rather than a new generic fibre, and the name could be used from 15 May 1996. The same notice records that Lenzing had a lyocell plant under construction. As of 2026, TENCEL™ is Lenzing’s trademark.

What are the properties of lyocell?

Lyocell is described by its makers as a strong cellulose fibre, wet or dry, with a smooth surface and a subtle sheen; its known weakness is a tendency to fibrillate when rubbed while wet. Most of these claims come from its makers:

• Strength. Courtaulds told the FTC its fibre had high wet and dry tenacity and a high wet modulus, from a more crystalline structure than other rayons. Lenzing describes TENCEL™ Lyocell as having high tenacity among cellulose fibres.
• Washability. Courtaulds claimed garments resisted shrinkage and wrinkling. The FTC itself cited washability as a significant difference between lyocell and other rayons when it approved the name.
• Handle and look. Lenzing describes the fibre as soft and smooth, with moisture control and a subtle sheen in fabric.
• Fibrillation. Courtaulds’ 1995 patent filing explains that wet, swollen lyocell fibres can split into fine fibrils when abraded. It notes that lyocell fabric is often more prone to this than other cellulose fabrics, while cotton has a very low tendency to fibrillate.

Claims that lyocell is “hypoallergenic” or “temperature-regulating” are marketing, not legal definitions; treat them as unproven without a named test.

Lenzing lists ready-to-wear, denim, intimates, footwear, activewear and home textiles among the uses of its TENCEL™ fibres. It says its TENCEL™ LUXE lyocell filament yarns make lightweight fabrics with a fluid drape and soft texture.

Lyocell vs viscose and modal: what is the difference?

Lyocell, viscose and modal are all regenerated cellulose fibres; EU law tells them apart by how the cellulose is turned into fibre, not by the plant it came from.

The plant source does not change the name. In the EU, a fabric sold as bamboo is still labelled by the process used to make it, for example as viscose or lyocell. Acetate is a different case again: US rules define it as a fibre made of cellulose acetate rather than regenerated cellulose.

How is lyocell graded or measured?

Lyocell has no legal quality grades: US and EU rules define only what may be called lyocell, not how good it is. The label measures quantity, as a percentage of the fabric’s weight; beyond that, look at the fibre’s maker and any certification.

How does lyocell appear on a clothing label?

Lyocell appears on the fibre-content label as “lyocell”, with its percentage by weight, and a brand name such as TENCEL™ may sit beside the generic name but cannot replace it.

In the US

• The label may say “lyocell” or “rayon” (16 CFR 303.7(d)).
• Fibres are listed by generic name and percentage by weight, in order of predominance.
• Fibres under 5% must be listed as “other fiber” rather than by name, unless the fibre has a clearly established functional purpose at that amount, such as 4% spandex for stretch (16 CFR 303.3). Wool is the exception: its name and percentage must always be stated, even below 5%.
• A trademark such as TENCEL™ must appear next to the generic name, in lettering of equal size and conspicuousness.
• The label must also give the country of origin and the name or registered identification number (RN) of the manufacturer, importer or another company selling or handling the product.

In the EU

• Only names listed in Annex I may describe fibre content, so the label says “lyocell”, never “Tencel” alone.
• Multi-fibre products list every fibre by name and percentage by weight, in descending order.
• A trademark may appear immediately before or after the fibre description.
• The label must be in the official language or languages of the country where it is sold, unless that country allows otherwise.

The UK Fashion and Textile Association (UKFT) gives the accepted format as “% Lyocell (TENCEL™)”. Read the percentages: in a lyocell and polyester shirt, or a jersey with elastane, the first-listed fibre is the largest by weight.

How do you tell good lyocell from poor lyocell?

Good lyocell is honestly labelled and has a clean, smooth surface with no white, hairy bloom from fibrillation; check the label first, then the cloth.

1. Read the label for the generic name. “100% Tencel” on its own is a red flag: US and EU rules both require the generic fibre name, with any trademark only beside it.
2. Check a brand claim. According to UKFT, using TENCEL™ on a product needs a product licence from Lenzing and the certification number supplied by the fabric mill. A seller using the name should be able to show this.
3. Look at the surface in daylight. Fibrillated fibres give a hairy look, and dyed fabric can look “frosted”. Courtaulds’ patent filing says heavily fibrillated fabric is considered substandard for most uses.
4. Check where the cloth is rubbed most. Fibrillation comes from abrasion while the fabric is wet, so on a washed T-shirt or shirt, a hairy or frosted patch at the seams or cuffs points to it.
5. Weigh up the blend. A fabric that is mostly synthetic with a little lyocell is mainly the synthetic fibre; the label percentage tells you which fibre dominates.

How do you care for lyocell?

Follow the care label, and keep wet friction low, because fibrillation happens when wet, swollen fibre is rubbed. Courtaulds’ patent filing notes that washing is one of the wet processes that can cause it, and that higher temperatures and longer treatment times make it worse. In practice that points to cooler, shorter washes and little rubbing while wet. The FTC treated washability as one of lyocell’s distinguishing traits, but the label has the final word.

Is lyocell sustainable?

Lyocell can be a lower-impact fibre, but most of the figures come from Lenzing and describe its branded fibre, not lyocell in general. Lenzing says that for TENCEL™ Lyocell:

• more than 99.8% of the solvent is recovered and reused;
• the wood comes from controlled or certified sources meeting FSC or PEFC standards;
• production uses at least 50% less carbon emissions and water consumption than generic lyocell, based on life-cycle assessment to ISO 14040/44 and Higg MSI data;
• its standard fibres are certified by TÜV AUSTRIA as biodegradable in soil, freshwater and marine environments;
• the fibres carry the EU Ecolabel and OEKO-TEX® STANDARD 100 class I certification.

Two cautions follow. Lenzing’s comparison with generic lyocell means its numbers do not apply to every lyocell label. And a biodegradability claim for a fibre is not a claim for a finished garment that also contains dyes, finishes or synthetic fibres. For the wider picture, see sustainable fashion.