Why do bra straps stretch?

Bra straps are engineered to stretch by design. These elastic components accommodate the natural shifts in your shoulders, posture, and breathing throughout the day while keeping your bra's cup edges and band properly seated against your body.

The stretch in your straps allows you to move freely without restriction, though the band itself carries the responsibility for delivering the majority of your support.

Over time, straps gradually lose their recovery ability through mechanical fatigue from daily wear, exposure to heat during laundering, body oils and sweat, and even UV light, which breaks down the elastane fibers that give straps their snap-back quality.

When your bra fits correctly with a firm, supportive band, your straps work as intended, providing stabilization and fine-tuning rather than bearing the full weight of support, which significantly extends their lifespan and maintains your comfort.