Why do bras lose elasticity?

Bras lose elasticity because the elastane (spandex) fibers that provide stretch and recovery undergo molecular changes over time, particularly when exposed to heat, moisture, and repeated wear cycles. Common accelerators of this breakdown include machine drying and hot water washing, which speed up the aging process, along with mechanical fatigue from daily wear that creates energy loss in the elastic fibers with each stretch cycle. Chemical exposure from chlorine bleach, fabric softeners, and even sweat and body oils further compromise the integrity of these elastomers, while environmental factors like UV light and ozone can cause additional degradation.

Cold water washing, air drying, and regular rotation help preserve bras' performance and extend their functional lifespan.