Modal, lyocell and viscose: the differences for clothing brands

Modal, lyocell and viscose are all regenerated cellulose: wood or plant pulp dissolved and spun back into fibre. Viscose is the original process and by far the most produced, with a soft drape but low wet strength. Modal is a modified viscose with higher wet strength, which is why it washes well in underwear and loungewear. Lyocell uses a different solvent that is recovered and reused, and gives the strongest fibre, wet or dry. On a label in the EU they must be called by exactly those names, and in the US “bamboo” is only allowed as “rayon made from bamboo”.

What modal, lyocell and viscose have in common

All three start as cellulose, usually from wood pulp, which is dissolved and forced through a spinneret to form a filament. None of them is a natural fibre in the legal sense, and none is a synthetic like polyester. EU Regulation (EU) No 1007/2011 lists them as separate man-made fibre names in its Annex I, and the US Federal Trade Commission treats them as forms of rayon, with lyocell allowed as its own generic name.

They are a small share of the fibre market. Textile Exchange’s Materials Market Report 2025 puts all man-made cellulosic fibres at about 8.4 million tonnes in 2024, roughly 6% of global fibre production. Within that, viscose was about 6.7 million tonnes, lyocell about 0.4 million and modal about 0.2 million. So viscose is the everyday fibre, and modal and lyocell are specialist ones.

How each fibre is made

• Viscose. Cellulose is converted into a soluble derivative using carbon disulphide, spun into an acid bath, and regenerated. A review in BioResources notes that carbon disulphide is an environmentally sensitive chemical and that its volatility can lead to losses and a negative environmental impact.
• Modal. The EU definition is a regenerated cellulose fibre made by a modified viscose process with a high breaking force and high wet modulus, and the regulation sets minimum values for both. In other words, modal is defined by its performance, not only its chemistry.
• Lyocell. Pulp is dissolved directly in an organic solvent, usually N-methylmorpholine N-oxide (NMMO), without forming a chemical derivative, then spun through an air gap into a coagulation bath. The EU and US definitions both hinge on that “no derivative” point. The BioResources review describes the residual solvent being recovered and recycled. Lenzing, the maker of TENCEL™ Lyocell, states that more than 99.8% of its solvent is recovered and fed back into the loop.

Modal vs lyocell vs viscose: side by side

Sources: EU Regulation 1007/2011 Annex I; FTC; BioResources review of lyocell (2018); Textile Exchange Materials Market Report 2025.

Strength, feel and drape

The BioResources review compares lyocell with viscose and finds lyocell about twice as strong when dry and three times as strong when wet, while viscose loses about half its tensile strength when wet. It attributes the difference to the higher orientation of lyocell’s structure. Lyocell also has lower elongation, so it stretches less before breaking.

Modal sits between the two. The same review describes modal as having very similar properties to regular rayon apart from its high wet strength, which allows modal garments to be machine washed and tumble dried and to perform much like cotton in similar end uses.

All three hold a lot of moisture. The EU regulation’s agreed allowances, the conventional moisture percentages used when calculating fibre content, are 13% for viscose, modal and lyocell, compared with 8.5% for normal cotton and 1.5% for polyester. That moisture is part of why they feel cool against the skin, and part of why they behave differently from cotton in washing.

Handle is still a matter of the finished fabric: yarn count, knit or weave, and finish change the feel more than a fibre name does. Judge by swatches of the actual construction, not by fibre alone.

Shrinkage, twisting and washing behaviour

Low wet strength has a practical cost. The BioResources review notes that regular rayon becomes unstable and may stretch or shrink when wet. A buyer should therefore test shrinkage on the finished fabric at the temperature the care label will show, before cutting, and write the care label from that result rather than from a template.

Viscose and modal jersey need the same discipline as cotton jersey, and more. Ask for shrinkage and spirality results on every fabric lot, and test the finished garment after several washes. Check seams too: a fabric that stretches when wet can grow along a seam while the stitching stays the same length, which shows as puckering after washing.

Lyocell has its own quirk. The review explains that its highly oriented structure can fibrillate: fine fibrils split away from the surface under wet abrasion. The review notes that it can be reduced through spinning conditions such as the air gap and draw ratio. At fabric stage, ask how the fabric has been finished, and wash-test a garment before approving bulk.

Environmental claims: what you can and cannot say

These fibres are often sold as sustainable, and that is where brands get into trouble.

• The process is not the same. The FTC states that rayon is typically made using environmentally toxic chemicals in a process that emits hazardous pollutants into the air. Lyocell’s solvent-recovery process is different, but a claim about it should name the fibre producer and cite its own data.
• Forest sourcing. Textile Exchange estimates that 65 to 70% of man-made cellulosic fibres in 2024 came from FSC or PEFC certified or controlled feedstock. The rest did not, so “made from sustainable wood” needs a certificate for your fibre, not the industry.
• Brand names need proof. A trade mark such as TENCEL™ belongs to its fibre producer, Lenzing, which sells both TENCEL™ Lyocell and TENCEL™ Modal. Only use a fibre brand when the fabric was made from that branded fibre and you can show the paperwork.
• Evidence first. The FTC’s guidance says claims need competent and reliable evidence. Keep fibre certificates and transaction documents for every order that carries a claim.

Our sustainable clothing manufacturing page explains how certificates are collected and checked before a claim goes on a swing tag.

Labelling rules in the EU and US, including “bamboo”

In the EU, Article 5 of Regulation 1007/2011 says only the fibre names listed in Annex I may be used to describe fibre composition on labels. Viscose, modal and lyocell are listed; “bamboo” is not a fibre name there. A trade mark may appear immediately before or after the fibre name under Article 16, as in “lyocell (TENCEL™)”, but it cannot replace it. The EU market page covers the other import requirements.

In the US, the FTC’s textile rules use rayon as the generic name, allow lyocell as a generic description, and permit the ISO names viscose and modal. A fibre trade mark may be used next to the generic name, in the same size of type. On bamboo, the FTC’s position is blunt: unless a product is made directly from bamboo fibre, it cannot be called bamboo, and a manufactured fibre made from bamboo pulp should be labelled as rayon, or “rayon made from bamboo”. In February 2010 the FTC warned 78 retailers to stop labelling rayon products as bamboo. The US market page covers the rest of the labelling rules.

What to ask a supplier before booking the fabric

Regenerated cellulose fabrics vary more between mills than their names suggest. Before you approve a fabric, get written answers to these questions:

• Which fibre, exactly? The legal fibre name and percentage for every component, including any elastane. A “modal blend” can be mostly cotton or mostly viscose.
• Who made the fibre? The fibre producer’s name, and any brand certificate if you plan to use a fibre brand on the swing tag.
• Which forest certificate? If you will say anything about wood sourcing, the FSC or PEFC certificate that covers your fibre.
• What do the tests say? Shrinkage at your care temperature, spirality for jersey, pilling and colour fastness, all on the finished fabric lot you will receive.
• How was it finished? Especially for lyocell, where finishing affects fibrillation.

Our fabric sourcing service collects these answers before a fabric is booked, so the label, the claim and the garment agree with each other.

Which one should your brand choose?

• Underwear, loungewear and nightwear: modal, often with a little elastane, for softness that survives washing. See our underwear and loungewear manufacturing page.
• Dresses and printed wovens: viscose for drape and price, with shrinkage tested at the care temperature. See dress manufacturing.
• Shirts, premium basics and blends where strength matters: lyocell, with a fibrillation and wash test on the finished fabric.
• Small first runs: our small-run loungewear route starts from 100 pieces per style and colour; ask which fabric qualities are available at that volume.

Whichever you pick, specify the fibre by its legal name, the fabric construction and weight, and the certificates you need. To price a range in any of the three, send us your tech pack.