Elastane—also called spandex—is a highly stretchable synthetic fibre normally used in small percentages with cotton, wool, viscose, polyamide or polyester. Its job is not to dominate the hand of a fabric but to help a garment stretch and return. Two per cent can make trousers recover at the knee; a much higher share supports activewear and close-fitting jersey.
What the percentage does not tell you
Stretch depends on yarn construction, knit or weave and direction, not only the number on the label. Pull the garment gently across and along the grain, then release it. Good material returns promptly without ripples, pale stress lines or a loose patch. Check waistbands, elbows, knees and seat, where heat and repeated extension first expose fatigue. More elastane is not automatically better: excessive tension can make a piece hot, restrictive or prone to permanent bagging.
Protecting recovery
Heat, chlorine, strong oxidising products, body oils and long storage under tension shorten elastic life. Follow the label, wash cool with a mild detergent and avoid fabric softener unless permitted. Do not leave a wet stretched garment hanging from narrow points. Dry away from radiators and direct sun; high tumble heat is especially damaging. Store relaxed, not folded around a tight hanger.
Choose elastane for measured freedom of movement. Fit, construction and recovery after wear matter more than the highest possible percentage.
