Rayon, Viscose, Modal, Bamboo, Lyocell: What the Tag Isn't Telling You

Stand in front of a rack and read six tags. Rayon. Viscose. Modal. Bamboo. TENCEL Lyocell. LENZING ECOVERO. All six fabrics started as wood pulp, and all six arrive at your skin as cellulose, the same plant material as cotton. On the Toxome Score they land anywhere from 64 to 88.

Twenty-four points, from an identical starting material. The gap has nothing to do with the tree.

What "semi-synthetic" means

Picture the spectrum. Cotton and linen sit at the natural end, where the plant grows a fiber you can spin straight into yarn. Polyester and nylon sit at the other end, built from petrochemicals into plastic thread. Everything in this article sits in the middle.

Semi-synthetics start with something that grew. Then the mill dissolves that cellulose into a syrup and pushes it through a showerhead of tiny holes to be reborn as thread. Rayon can feel like silk and still require a chemical plant to exist.

So plant-based describes the feedstock and nothing else. Two mills can take the same pulp and hand you very different cloth.

Rayon is a family, not a fiber

Rayon is the umbrella. It covers every regenerated cellulose fiber, and it has been around for over a century, invented to imitate silk. Viscose, modal, and lyocell all sit underneath it.

In the United States a tag will usually say rayon where a European tag says viscose. Same thing. When a label gives you that word and stops, it has told you what the fiber is and nothing about how anyone made it.

Viscose is the default, and the default has a problem

Viscose is the most common member of the family, and it explains why the drape on a good rayon dress beats cotton. Soft hand, cool against skin, that liquid fall through the hips.

The process behind it dissolves wood using caustic soda and carbon disulfide. That second chemical is the issue. It damages the nervous system of people exposed to it over time, and in mills that run cheaply it escapes through the air and the water. The Changing Markets Foundation followed that pollution down the supply chain and found rivers running discolored beside the factories.

You cannot feel any of that through the fabric. A twenty-five dollar viscose dress and a carefully sourced one hang the same way on the rack.

Bamboo is viscose wearing a nicer word

Bamboo fools more shoppers than the rest of the family combined.

The plant grows fast, needs little water, and takes no pesticides, which is true and stops mattering the moment it reaches a mill. Turning a woody stalk into something soft takes the viscose process. Same caustic soda, same carbon disulfide, same factories. A bamboo tee and a generic viscose tee are chemically the same garment.

Regulators agree. US labeling rules require the word rayon on that tag, or rayon made from bamboo. In 2022 the FTC fined Kohl's and Walmart a combined 5.5 million dollars for selling rayon as "bamboo" and calling the process ecofriendly, the largest penalty it has ever won in this area. Both had been warned in 2010 and kept doing it. We score bamboo where the chemistry puts it, at 64, alongside generic viscose.

One exception is real. Bamboo lyocell exists, made through the closed-loop process below, and it behaves like a different fiber. Brands that pay for it say so on the tag. If the tag says bamboo and nothing else, assume viscose.

Bamboo tells you what the mill started with. It tells you nothing about what the mill did.

Modal is viscose with better manners

Modal turns up in underwear, sleep sets, and soft tees, and it is a step up. Producers make it from beech pulp through a modified viscose process that leaves the fiber stronger when wet, so it survives washing better and pills less than plain viscose.

It still runs the viscose route. Still carbon disulfide. Generic modal earns a 70 on our scale, six points above viscose, and that lift comes from performance and pulp sourcing rather than any change in chemistry.

TENCEL Modal is Lenzing's branded version, produced with recovery systems that capture most of what the process uses, and it earns a 74. Worth naming, because those two tags sit four points apart and neither one explains why.

Lyocell changes the chemistry

TENCEL is a brand. Lyocell is the fiber. Keeping those separate is most of what people get wrong here.

Lyocell dissolves the same wood using NMMO, a solvent not classified as toxic, inside a closed loop. Closed loop is a plain idea wearing an industrial name: the mill captures what it uses and feeds it back in rather than letting it out. Recovery runs above 99 percent, documented in the journal Fibers.

It also happens to be the better fabric. Stronger wet, smoother, more absorbent, less prone to pilling. Because it is cellulose rather than plastic, it does not shed the persistent microplastic fiber that polyester and nylon do. It earns an 88, the highest score in the family.

One caveat. A garment can say lyocell without being TENCEL, and generic lyocell producers vary in how much solvent they recover. The named brand is the version you can verify.

ECOVERO is better viscose, not lyocell

LENZING ECOVERO is viscose. It runs the same viscose chemistry as everything in section four.

Lenzing changed everything around that chemistry: certified and controlled wood sources, traceability built into the fiber, EU Ecolabel certification, and by their own accounting at least half the carbon emissions and water of generic viscose.

That is a real improvement and we score it as one. ECOVERO earns an 80, sixteen points above the generic viscose it replaces. Given a choice between a tag that says viscose and a tag that says LENZING ECOVERO viscose, take the second one without thinking about it.

Do not file it next to lyocell, though. The sourcing got better. The solvent did not change.

What any of this means against your skin

We will not overstate this, because overstating it is how the subject gets silly.

The thread in your shirt is cellulose no matter which of these you bought. The mill spends the carbon disulfide during production, and none of it rides home in your shirt. Viscose scoring 64 rather than 20 reflects that. It is a middling fiber for the wearer, and the worst of the harm falls on the people in the mill and the town downstream.

The lower scores reflect uncertainty you cannot see from the fitting room. Generic viscose tells you nothing about which mill made it or what anyone recovered. It also tends to arrive with heavier dye loads and easy-care finishing, and those finishes can release formaldehyde, which irritates skin and is a known carcinogen. A named process removes most of that guesswork. You are buying certainty as much as you are buying fiber.

The hierarchy, in one place

What to do at the register

If two pieces are otherwise equal and one says lyocell, take the lyocell. It is the better fabric sitting on top of the better process.

If you love something that says viscose, rayon, or bamboo, you do not have to put it back. Look for a named process instead of a bare fiber name: TENCEL, ECOVERO, or a brand willing to tell you where its pulp comes from. Then check the finished garment for OEKO-TEX STANDARD 100, which tests the thing you will wear for formaldehyde and harmful dyes. Skip anything sold as wrinkle-free or no-iron whatever the fiber, and wash it before the first wear.

A clean fiber does not guarantee a clean garment. Dyes, finishes, elastane, and hardware all count, and a finishing spray can undo a well-sourced lyocell.

The tag stops at the fiber name as though the word settles the question. Ask which process, and which mill. Ask what happened between the tree and your skin.