Most jeans today aren’t made from 100% cotton. They usually contain Lycra or elastane, which gives them flexibility and a flattering fit. Unfortunately, these fibers are extremely sensitive to heat.
High temperatures in the washer or dryer cause Lycra to deteriorate. When that happens, the surrounding cotton fibers shift and warp unevenly. Instead of shrinking evenly like pure cotton, stretch denim develops random ripples and puckers.
Once the elastic fibers are damaged, the change is permanent—there’s no way to fully restore the fabric.
Overwashing makes this worse. Jeans don’t need to be washed after every wear, and frequent washing accelerates fiber breakdown and ruins their shape.
2. The Washing Machine Stretches and Twists the Fabric
Even without excessive heat, the washing machine itself can cause problems. Jeans don’t simply soak in water—they’re tossed, twisted, and pulled in multiple directions.
Overloading the washer makes this worse. When clothes are packed too tightly, denim gets stretched unevenly as it tangles with other garments.
Stretch denim is especially vulnerable when wet and heavy. Different areas dry under different levels of tension, which leads to that familiar wavy, rippled appearance once dry.
