Why clothes shrink and how to unshrink them
Your favorite cotton shirt didn’t shrink because you did something wrong. It shrank because the fibers finally relaxed. Natural fibers like cotton and linen contain millions of tiny cellulose molecules that naturally exist in coiled, crinkled shapes, reports The Conversation. During manufacturing, these fibers get mechanically straightened and held in place by hydrogen bonds. Heat, moisture, and the tumbling of your washing machine weaken those bonds, and the fibers recoil back to their natural state. Your shirt didn’t get smaller — it stopped pretending to be bigger.
Cold water doesn’t save you, either. Cellulose is hydrophilic, meaning it attracts water. Water molecules penetrate the fibers, making them swell and loosen their structure. Wool has its own problem: the cuticle scales on wool fibers open up and interlock with neighboring fibers in a process called felting, making the fabric denser and smaller. Synthetics like polyester resist shrinking because they have crystalline regions that act as an internal skeleton.
But here’s the useful part: you can unshrink clothes. Soak the shrunken garment in lukewarm water with about a tablespoon of hair conditioner or baby shampoo per liter. The conditioners contain cationic surfactants that temporarily lubricate the fibers, letting you gently stretch the fabric back toward its original shape. Lay it flat to air dry. It’s not magic — it’s just chemistry working in the opposite direction for once.