Fibre encyclopedia
Elastane
Also called elastane · spandex · Lycra · elastan · EL · elastane spandex · spandex elastane
The fibre that makes cloth stretch and come back. It appears on labels in small percentages, and it decides two large things.
Class
Synthetic
Comes from
From oil or gas
Where it comes from
Elastane is a segmented polyurethane. Labelling rules use the name when at least 85 per cent of the mass is segmented polyurethane and the fibre returns close to its original length after being stretched to three times that length. The same fibre is called spandex in North America and sold under the brand name Lycra, which is the reason a reader cannot always match one label to another.
How it feels to wear
Air
Little air moves through the fibre
Water
Water stays on the surface
Heat
Neither holds nor sheds heat
Stretch
Stretches and returns
Wear
Wears down sooner under rubbing
Elastane loses its return before the cotton or polyester around it wears out, so the wear life of a stretch cloth is usually set by the elastane in it rather than by the fibre that makes up most of its mass. Heat, chlorine and fabric softener each shorten that. A cloth with elastane also sits closer to the skin, because that is what it was put there to do.
Care
- Wash cold, and keep it out of the hot dryer.
- Skip fabric softener and chlorine.
- Dry flat so the stretch panels do not hang under their own weight.
- Rinse swimwear in fresh water after pool water.
Everything that shortens elastane life is a heat or a chemical, which is why the care line on stretch cloth reads as a list of things not to do.
End of life
Recycling route
No route running at scale
Elastane has no volume recycling route of its own, and it removes the route the fibre it was blended into would otherwise have had. Sorting lines detect it by infrared, and cloth containing it is separated out rather than processed.
In a blend
A small share of elastane places the rest of the fibre outside mechanical recycling, because fibres spun together cannot be separated again.
Skin notes
Mechanical
Stretch cloth sits tighter against the skin, so friction and surface warmth are higher than they are under a cloth that hangs loose. That is a fit effect, not a fibre reaction.
Chemical
Elastane is a polyurethane and is not the same material as rubber elastic, which is made with rubber accelerators and appears in waistbands and cuffs. A label separates neither, and it names no dye or finish either.
If your skin reacts to a garment, a dermatologist and patch testing are what can answer it. A label cannot, and neither can this page.
What the label cannot tell you
The label gives a percentage for elastane. It does not say that this share usually decides when the cloth stops returning to shape, and that it places the rest of the fibre outside mechanical recycling.
Sources
- Regulation (EU) No 1007/2011 on textile fibre names and related labelling, Annex I. Checked 22 August 2026
- ISO 2076:2021, Textiles, man-made fibres, generic names. Checked 22 August 2026
- European Commission Joint Research Centre, techno-scientific assessment of the management options for used and waste textiles in the European Union, 2023
Written from primary sources and in our own words. Where a figure could not be traced to a source anyone can open, it is not printed here.
Read the label you are holding
The scan surface reads one care label and names which questions it answers and which it leaves out. A passport says for one specific piece what a label cannot: the composition with its percentages, where the cloth came from, who worked on it, how to repair it and where it goes next.