Lyocell is one of the more sustainable fabric options available today, though how sustainable depends on the sourcing, the manufacturer, and what the fabric is blended with. Its core advantages are a closed-loop production process that recovers up to 99.5% of its solvent, water usage roughly a third of cotton’s, and full biodegradability in about a month. But those advantages come with caveats worth understanding.
How Lyocell Is Made
Lyocell is a regenerated cellulose fiber, meaning it starts as wood pulp and gets dissolved into a liquid before being spun into fiber. The solvent used is a compound called NMMO, a non-toxic tertiary amine oxide. What makes the process notably clean is that the NMMO doesn’t get discarded after use. It’s captured and fed back into the system in what’s known as a closed-loop process.
Recovery rates for this solvent reach 99% to 99.5% depending on the system configuration. That means almost none of the chemical input escapes into wastewater or the surrounding environment. This is a significant improvement over conventional viscose (rayon) production, which uses carbon disulfide, a toxic chemical linked to health problems in factory workers, and generates substantial air and water pollution.
Water and Energy Use Compared to Cotton
Producing one kilogram of lyocell fiber requires roughly 600 to 800 liters of water. The same amount of cotton takes around 2,700 liters. That’s about 65 to 75% less water, which matters in a world where textile production is one of the largest industrial consumers of freshwater. The trees used for lyocell, particularly eucalyptus, also grow quickly on relatively little land without heavy irrigation or pesticide use, unlike conventional cotton farming.
Energy consumption during manufacturing is also lower than both cotton processing and conventional viscose production, partly because the closed-loop system reduces the need for extensive chemical treatment and wastewater processing.
Where the Wood Comes From
Lyocell is typically made from wood pulp sourced from beech, spruce, birch, aspen, pine, and eucalyptus trees. The largest producer, Lenzing (which sells lyocell under the TENCEL brand), sources from semi-natural forests in Europe and FSC-certified eucalyptus plantations in places like Brazil. An independent assessment by the environmental nonprofit Canopy found no known risk of Lenzing sourcing from ancient or endangered forests.
That said, not all lyocell comes from Lenzing. Other manufacturers may not maintain the same sourcing standards, and the fiber name alone doesn’t guarantee responsible forestry. Look for FSC or PEFC certification on the product, which verify that the wood was harvested from responsibly managed forests. Lenzing’s fibers also carry OEKO-TEX Standard 100 certification, meaning the finished product has been independently tested for harmful substances.
Biodegradability Is a Real Advantage
One of lyocell’s strongest sustainability claims is how quickly it breaks down at end of life. In marine environment experiments conducted by researchers at the Scripps Institution of Oceanography, lyocell fabric disintegrated in roughly 26 days on the sea surface and 25 days on the seafloor. Natural and regenerated cellulose fibers generally biodegrade completely within about 35 days. For comparison, petroleum-based synthetics like polyester showed no sign of disintegration even after 428 days in the same conditions.
This also matters for microfiber pollution. All fabrics shed tiny fibers during washing, and those fibers end up in waterways. When polyester sheds, those microfibers are essentially microplastics that persist in the environment indefinitely. When lyocell sheds, the cellulose-based fibers biodegrade within weeks in water. That’s a meaningful difference for ocean and freshwater ecosystems.
The Blending Problem
Pure lyocell garments carry the sustainability benefits described above. But lyocell is frequently blended with polyester or other synthetic fibers to improve durability, reduce cost, or change the fabric’s drape. These blends create two problems.
First, a lyocell-polyester blend is no longer fully biodegradable. The polyester component will persist in the environment just as it would in any synthetic garment. Second, blended fabrics are extremely difficult to recycle. Most textile recycling technologies at commercial scale can only handle single-material fabrics. Separating tightly interwoven fibers of different types requires chemical processes that often degrade fiber quality. Some newer technologies can dissolve the cellulose component and recover the polyester separately, but these are not yet widely available. If you’re buying lyocell specifically for its environmental benefits, check the label for 100% lyocell or TENCEL content.
Dyeing and Finishing Still Matter
The fiber itself is only part of the story. Dyeing and finishing processes can add a significant chemical footprint to any textile, and lyocell is no exception. Most commercial lyocell fabrics are dyed with reactive dyes, the same synthetic dyes used across the textile industry. The dyeing process involves salt, alkaline chemicals, and heated water baths.
Lyocell does have one advantage here: its smooth fiber surface absorbs dye more evenly, which can reduce the number of chemical treatments needed and lower the amount of unfixed dye that washes out as wastewater. Research on ultrasonic dyeing methods for lyocell has shown the potential for significant reductions in salt use, energy input, and processing time while actually improving color yield. But whether a particular manufacturer uses these more efficient methods varies widely.
Where Lenzing Is Heading
Lenzing, which dominates the lyocell market, currently sources 72% of its biological materials from sustainably certified origins and uses 48% recycled or reused components across its total material inputs. The company has set goals to increase recycled content in its lyocell and viscose fibers from 20% to at least 30% post-consumer waste by 2030, and to incorporate at least five alternative feedstock sources including recycled textiles and agricultural waste. Lenzing was also the first cellulose fiber producer to set science-based targets for reducing greenhouse gas emissions, approved by the Science Based Targets initiative.
The Bottom Line on Sustainability
Lyocell is genuinely more sustainable than most textile alternatives across several key metrics: water use, chemical pollution during manufacturing, biodegradability, and microfiber impact. It outperforms cotton on resource consumption and polyester on end-of-life impact. It also improves substantially on conventional viscose, which uses the same raw material but a far dirtier production process.
The caveats are real but manageable. Sustainability depends on the specific manufacturer’s practices, whether the wood is responsibly sourced, what the fabric is blended with, and how it’s dyed and finished. A 100% lyocell garment from a certified producer with FSC-sourced wood is among the better choices in mainstream textiles. A lyocell-polyester blend from an uncertified producer is a different product entirely.