What is lyocell? 9 questions answered before you sleep on it

Written by Derek Fontaine
Research and Development Scientist at Sleep Research Institute of the Rockies · Last updated: August 2026

Lyocell is a fiber spun from wood pulp, usually eucalyptus, that has been dissolved in a non-toxic solvent and pushed through microscopic nozzles to form smooth, uniform filaments. It is not a plant fiber like cotton, and it is not a plastic like polyester. It belongs to a third category called regenerated cellulose: plant material, taken apart and rebuilt. That process is why lyocell fibers measure 10 to 12 microns, finer than cashmere, and why the fabric behaves so differently against your face during the 8 hours you are lying on it.

Here is the part almost every fabric guide leaves out. Lyocell is a category, not a quality grade. Two products can both be labeled 100% lyocell and perform nothing alike, because what happens to the fiber after it is spun matters as much as the fiber itself. CloudThera™, the eucalyptus lyocell behind Dreamey bedding, is one specific engineered version of it. Below are the 9 questions worth answering before you sleep on any of them.

In this article

• 1. What is lyocell, exactly?
• 2. How is lyocell made?
• 3. Is lyocell natural, synthetic, or plastic?
• 4. Lyocell vs TENCEL vs modal vs viscose: what is the difference?
• 5. Is lyocell breathable, and how does it compare to cotton?
• 6. Is lyocell good for your skin and hair?
• 7. Is lyocell toxic, or safe for sensitive skin?
• 8. Does lyocell shrink, stretch, or pill?
• 9. What are the disadvantages of lyocell?

1. What is lyocell, exactly?

Lyocell is a generic fiber name, the same way polyester and nylon are generic fiber names. It is not a brand, and no single company owns it. To qualify as lyocell, a fiber has to be made of cellulose that was dissolved in an organic solvent and spun directly into filament, without the chemical intermediate step that older wood-based fibers require.

The measurable consequence is fineness. Lyocell filaments come off the line at 10 to 12 microns, against 15 to 20 microns for premium cotton, per Lenzing AG fiber specifications. Cashmere, the reference point most people have for softness, sits at roughly 14 to 19 microns. A finer fiber packs into a more uniform surface with fewer protruding ends, which is why the fabric registers as smooth on first contact rather than after 20 washes of breaking in.

2. How is lyocell made?

Wood is chipped, cooked into pulp, and reduced to pure cellulose. That cellulose is dissolved in NMMO, an amine-oxide solvent that is biodegradable and non-toxic, then extruded through spinnerets into a bath where the fiber solidifies. The solvent is washed out and captured.

That last step is the one that matters. The lyocell process runs closed-loop, recovering 99.5% of its water and solvents for reuse, as documented in the EU BREF Report (2020); Lenzing reports figures above 99.8% at its own sites. Older wood-based fibers are made by converting cellulose into a soluble compound using carbon disulfide, then converting it back, with far more of the chemistry leaving the factory. Same tree, entirely different process, entirely different fiber.

3. Is lyocell natural, synthetic, or plastic?

Semi-synthetic is the accurate answer. The raw material is 100% plant-based, and the finished fiber is chemically still cellulose, so it biodegrades. But it does not grow in that form, so calling it natural in the way cotton or linen is natural overstates it.

Lyocell is definitely not plastic, and it is not polyester. Polyester is polymerized from petroleum, sheds microplastics, and does not break down. Lyocell starts as a tree, ends as cellulose, and is recognized as vegan by PETA. If a label says lyocell and the fabric feels slick and static-prone the way polyester satin does, check for a blend, because those are two very different materials doing two different things to your skin.

4. Lyocell vs TENCEL vs modal vs viscose: what is the difference?

These four words get used as if they were interchangeable, and they are not. They describe one family of wood-based fibers made by three different processes, plus one brand name sitting on top. Once you can tell them apart, most bedding marketing becomes readable.

The bamboo row is not a matter of opinion. The Federal Trade Commission has pursued sellers for years over labeling rayon textiles as bamboo, including penalties totaling $1.3 million against four national retailers, and it publishes guidance on bamboo textile claims for exactly this reason. If you are weighing these materials against each other for a bed specifically, we go deeper in our eucalyptus vs bamboo vs cotton comparison.

Where CloudThera sits on that family tree

CloudThera is a lyocell, so everything true of the category is true of it: closed-loop, plant-based, fine, strong when wet. What separates it is the step after spinning. The fiber is finished with DermaWeave™, the proprietary finishing process that sets the surface geometry of the woven fabric rather than coating it, so the smoothness is structural and does not wash out.

That distinction is the practical reason to care about this section. A commodity eucalyptus lyocell set and an engineered one can carry the same fiber name at wildly different prices, and the honest tell is simple: ask what the surface measures. Commodity eucalyptus viscose and entry-level lyocell publish no such numbers, which is why they compete on adjectives. We publish ours because they were measured, not marketed.

5. Is lyocell breathable, and how does it compare to cotton?

Yes, and the mechanism is different from cotton's, which is the part worth understanding. Cotton is absorbent: it soaks up moisture and holds it in a damp layer at the surface, against your skin. Lyocell pulls moisture into the core of the fiber and releases it as vapor from the other side.

Measured as moisture vapor transmission rate, CloudThera moves 570 g/m²/h against premium cotton's 425 g/m²/h, which is 34% greater moisture vapor transmission, per independent textile laboratory testing. In practice that is the difference between waking up at 3am to flip your pillow and sleeping through. The fiber also holds roughly 11% moisture regain, meaning moisture stored inside the fiber structure, against cotton's 8%, per Lenzing AG specifications. More moisture inside the fiber means less of it sitting on your face.

One clarification, because the two get confused constantly: fiber and weave are separate variables. Lyocell is the fiber; percale and sateen are weaves, and they change how any fiber breathes and feels. Our percale vs sateen guide covers that layer, and if heat is your main complaint, the breathability ranking of 6 fabrics puts numbers to all of them. Note that temperature-regulating is the accurate description here, not a fabric that makes you cold.

6. Is lyocell good for your skin and hair?

This is where the fiber's geometry stops being trivia. Two properties do the work, and both are measurable.

The first is drag. CloudThera's surface measures 0.11 µm of roughness against premium cotton's 0.25 µm, which is 56% less friction, per textile surface metrology testing. Every time you turn your head, a rougher surface tugs at skin and hair strands instead of letting them slide. Less tugging over 8 hours means fewer sleep creases in the morning and less of the frizz and breakage that shows up along your hairline.

The second is what lives on the surface. Because the fiber holds moisture internally instead of pooling it at the surface, CloudThera harbors 3x less surface bacteria than cotton and 60% less odor, per the Hohenstein Institute textile hygiene testing program. Cotton's damp surface layer of sweat, oil, and skin cells is a hospitable place; a drier surface is not.

Two honest limits. No fabric erases a line you already have; the surface you sleep on governs what happens during the 8 hours, not the years before them. And bedding is not a treatment for a skin condition. What a smoother, drier surface does is stop working against the skincare you already paid for.

7. Is lyocell toxic, or safe for sensitive skin?

Lyocell is not toxic. The solvent involved, NMMO, is non-toxic and biodegradable, and in a closed-loop line it is recovered and reused rather than discharged. It is also washed out of the fiber during production, so it is not present in the fabric you sleep on.

For sensitive skin the certification is what to look for, not the fiber name. CloudThera is OEKO-TEX Standard 100 certified, meaning every component was tested against a list of harmful substances, and certified hypoallergenic and dust-mite resistant by the Hohenstein Institute. The fiber is also naturally anti-static, because moisture held inside the fiber dissipates electrical charge before it can build up, and that is a permanent physical property rather than a finish that washes off. Static is what makes a fabric attract and hold dust against your face.

8. Does lyocell shrink, stretch, or pill?

Shrinking: minimal, and mostly on the first wash. Wash cool and tumble dry low and a well-made lyocell sheet holds its dimensions. High heat is what causes trouble, as it is with most cellulose fibers.

Stretching: lyocell itself is not a stretch fiber. It has fluid drape, which reads as give when you handle it, but any real elasticity in a lyocell product comes from added elastane. For bedding that is a feature, since a fitted sheet should recover its shape rather than relax out of it.

Pilling: here the category earns its bad reviews. Buyers of inexpensive eucalyptus sets routinely report fuzz balls within a few washes, and at least one seller openly recommends combing them off with a razor. That is not lyocell failing. It is short fiber lengths, loose spinning, and blended filler failing, and it is why a commodity set can feel identical in the store and look worn out in a month. Properly spun lyocell tests at 38 cN/tex tensile strength, centinewtons per tex being the textile industry's measure of fiber strength, which is 50% stronger than cotton per Lenzing AG specifications, and unlike viscose it keeps that strength when wet, which is exactly when a fabric is most vulnerable in the wash.

Worth flagging: you will see products advertised as 1,000 thread count lyocell blends, and that number is doing the opposite of what you think. Our guide to thread count explains why a lower honest count outperforms an inflated one.

9. What are the disadvantages of lyocell?

A fair list, because a guide that admits nothing is not worth reading:

• It costs more than cotton. Closed-loop solvent spinning is a more expensive process than growing and ginning cotton, and the price reflects it.
• Quality varies more than in almost any other fiber category. The label tells you the process, not the fiber length, the spin quality, or the finishing.
• Blends dilute it. A lyocell blend can be mostly polyester and still lead with the word lyocell on the packaging.
• It creases in the wash. Less than linen, more than polyester. Shaking it out damp handles it.
• It is not a medical product. A better surface is a variable you control, not a treatment.

Read that list again and notice how much of it describes cheap lyocell rather than lyocell. That is the single most useful thing to take away from this page. When you are comparing two sets with the same fiber on the label, the question is never whether it is lyocell. It is what the surface measures, who measured it, and what happened to the fiber after it was spun.

Frequently asked questions

Is lyocell the same as bamboo?

No. Lyocell describes a closed-loop solvent process, while fabric sold as bamboo is almost always viscose made from bamboo pulp using older carbon-disulfide chemistry. A bamboo lyocell does exist, but it is uncommon, and the word bamboo on a label tells you the plant, not the process. The FTC has taken repeated action over this exact confusion.

Is lyocell more expensive than cotton?

Usually yes, per set. The more useful comparison is cost per year of use, since lyocell tests 50% stronger than cotton at 38 cN/tex per Lenzing AG, holds that strength wet, and softens rather than degrades with washing. A set that survives 3 years of laundering is cheaper than 2 sets that do not.

Can you put lyocell in the dryer?

Yes. Machine wash cool and tumble dry low. That is one of lyocell's real advantages over silk, which needs hand-washing and air-drying to survive. High heat is the only thing to avoid, since it is what drives shrinkage in any cellulose fiber.

Is lyocell hypoallergenic?

Not automatically, and that distinction matters: hypoallergenic is a certification held by a specific product, not a property of the fiber category. The underlying mechanism is real, though. Dust mites need humidity, and lyocell holds moisture inside the fiber rather than pooling it at the surface, while its anti-static behavior means it does not pull dust toward your face. CloudThera is certified hypoallergenic and dust-mite resistant by the Hohenstein Institute, and OEKO-TEX Standard 100 certified for the absence of harmful substances. Look for the certification rather than assuming it from the word lyocell.

How can you tell if something is real lyocell and not a blend?

Read the fiber content line, not the marketing line. It must state 100% lyocell; anything reading lyocell blend or containing polyester is a different material with different behavior. Then ask for measurements. A brand that has tested its fabric can tell you the surface roughness and the moisture vapor transmission rate. A commodity supplier will answer with adjectives.