What is modal fabric?
Modal is a type of rayon, the family of fibres made from regenerated wood-pulp cellulose. Its technical name is high-wet-modulus, or HWM, rayon, and it is spun from the pulp of beech trees. Like viscose and lyocell, it starts from a plant but is chemically dissolved and re-formed, which makes it a man-made cellulosic.
The point of modal is that it fixes viscose's biggest flaw. Ordinary viscose loses much of its strength when wet and shrinks; modal is engineered to stay strong and stable when wet. That is why it feels like a smoother, more durable viscose, and why it is a default for underwear, soft tees, and bed linen.
Two things to get straight up front. Modal is not a natural fibre, whatever a hangtag implies: the beech is renewable, but the fibre is manufactured. And it sits between recycled cotton and the synthetics as a semi-synthetic, the same middle ground as viscose and lyocell.
Modal is a fibre, not a brand
This trips up a lot of buyers. Modal is a generic fibre name, defined under the ISO 2076 standard, and any producer can make it. The familiar names, Lenzing Modal, MicroModal, and Tencel Modal, are brands: they are one company's certified version of the generic fibre.
- Modal: the generic HWM rayon, made by many mills. Quality and sourcing vary, and a garment can be pure modal without being a branded one.
- Tencel Modal and MicroModal: Lenzing's branded modal, backed by certified beech sourcing and documentation. MicroModal is simply a finer version of the same fibre, used for very soft, lightweight fabrics.
There is also a labelling quirk worth knowing: in the United States, modal is not a separate fibre name under the rules, so a US label often reads rayon rather than modal even when the fibre is modal.
For a brand, the distinction matters the same way it does for lyocell. A bolt marked simply modal tells you the fibre type and nothing about who made it or how carefully; a bolt marked Tencel Modal or Lenzing Modal tells you both, and comes with the paperwork a sustainability claim has to rest on. Generic modal can be very good or quietly mediocre depending on the mill, and much of the cheapest supply comes from producers with looser environmental and labour standards.
How modal is made
Modal is made by a modified version of the viscose process, and the modifications are exactly what give it its strength. It runs close to viscose with two key differences.
- Beech pulp: modal is characteristically made from beech, purified into dissolving pulp, whereas viscose can be made from a wide range of woods and bamboo.
- A gentler viscose route: the pulp is steeped in weaker caustic soda than standard viscose and treated with carbon disulfide to form cellulose xanthate, then dissolved into a spinning solution, using lower chemical concentrations along the way.
- Stretching for strength: as the fibre is spun and coagulated, the filaments are stretched, around three times their length, before they fully regenerate. That stretch aligns the cellulose into longer, more crystalline chains, which is what produces the high wet modulus.
So modal is not a cleaner chemistry than viscose in kind: it still uses carbon disulfide, so it is not the closed-loop process that lyocell uses. It is a refined viscose that trades a little absorbency for a lot of wet strength and stability.
The approach is not new. High-wet-modulus rayon grew out of industrial fibres developed in the 1930s, and one early textile form, polynosic, was developed by the Japanese researcher S. Tachikawa in 1951 to give rayon a structure closer to cotton. Modal is the European generic name for this high-wet-modulus family, and Lenzing later made it the basis of its branded modal lines.
Modal properties: strengths and the trade-off
Modal reads like a premium viscose that behaves better in the wash. Its strengths cluster around durability and hand, with one honest trade-off.
- Soft and silky: modal has a smooth, cool, fluid hand, often compared to mercerised cotton or silk, which is why it suits next-to-skin pieces and why it can, like cotton, be mercerised for extra strength and lustre.
- Strong and stable when wet: its defining property; modal keeps most of its strength when wet and resists the shrinking and distortion that affect viscose, so it launders well and can usually be machine washed where viscose often cannot.
- Low pilling and hard-wearing: it resists pilling better than cotton and holds up to repeated washing, so garments keep their look longer and resist the fuzzing that ages a cheaper fabric.
- Breathable and moisture-wicking: it breathes well and moves moisture off the skin rather than trapping it, which is why it feels cool to wear and is popular in activewear and bedding alike.
- The trade-off: modal is slightly less absorbent than ordinary viscose, a side effect of its denser, more crystalline structure, so it wicks and dries rather than soaking up like a towel. That is a feature for activewear and a reason it is rarely used for bath towels.
Because modal's selling point is dimensional stability, it is worth confirming it with a shrinkage and colourfastness check, and setting the care label to the finished fabric rather than assuming the fibre alone.
Modal vs viscose, lyocell, and cotton
Modal is easiest to place inside its own family. It is the middle child of the cellulosics: stronger than viscose, but made with older chemistry than lyocell.
- Modal vs viscose: same basic process, but modal is stretched and made with gentler chemistry, so it is stronger and more stable when wet, lower-shrink, and lower-pilling. It costs a little more, and in many markets it has largely replaced plain viscose for that reason.
- Modal vs lyocell: lyocell (often Tencel) is made in a closed loop with a non-toxic solvent, so it is the cleaner fibre and the strongest when wet; modal still uses carbon disulfide. Lyocell usually costs more.
- Modal vs cotton: modal is softer, silkier, more pilling-resistant, and more dimensionally stable, but less absorbent and not a true natural fibre; cotton is natural and more absorbent, which is why the two are so often blended together.
For a brand, the read is straightforward: modal when you want a soft, wash-stable upgrade on viscose at a modest premium, lyocell when the lowest-impact process is the priority. In practice the three are often blended, so a fabric is rarely one fibre, and the composition and the producer on the label are what actually decide how it performs and how clean it is.
What modal is used for
Modal earns its place wherever softness has to survive repeated washing. It leans toward close-to-skin and easy-care pieces, and it is often described as the underwear fibre because that is where its combination of soft hand and wash durability matters most.
- Underwear and basics: modal is the classic underwear and soft-tee fibre, prized for a smooth hand that lasts through frequent laundering without going rough or baggy, where MicroModal in particular gives an especially fine, light feel.
- Activewear: its moisture-wicking and durability suit leggings, loungewear, and light performance pieces, often blended with elastane for stretch and recovery.
- Bedding: modal sheets are sold as soft, cool, and hard-wearing, a growing end use for the fibre thanks to its silky hand and resistance to pilling over many washes.
- Blends: modal is widely blended with cotton or synthetics to lend softness and stability, and MicroModal is used where an especially fine, light hand is wanted.
Is modal sustainable, and how to source it
Modal is a step up from conventional viscose, but it is not automatically green, and the honest spec treats it that way. Its impact sits upstream, in the forest and the mill, so that is where a brand's choices actually land rather than in the fibre name on a swing tag.
- Better, not clean: the gentler chemistry and reduced waste make modal cleaner than standard viscose, but it still uses carbon disulfide, so it is not in lyocell's closed-loop class, and the environmental gap between a well-run mill and a cheap one is large.
- The wood and the brand: branded modal such as Tencel Modal uses FSC or PEFC certified beech and comes with documentation; generic modal, often from mills with looser standards, may not, so sustainable sourcing is where the real difference is made.
- Not natural, not organic: modal is semi-synthetic, so it cannot be certified organic, and calling it natural is the sort of claim that fails under the green claims directive; pure modal from a named producer can, though, be certified biodegradable.
- Spec it deliberately: choose the grade and blend on purpose, verify the wood and the producer, and reproduce the quality and care specs across textile manufacturing for the whole run.
Knowing which cellulosic, which grade, and which certification fit a given garment is the fashion-native detail Apshan's Nari knowledge graph answers, cited to source, inside the AI assistant your team already uses. Request access.