Spandex-blend fabric can shrink slightly with heat, the fix is cold water and air drying, not avoiding the fabric altogether.
What Actually Causes Shrinkage
Heat is the main culprit, both from hot water and a dryer's heat cycle. Spandex fibers lose elasticity and contract when exposed to high heat repeatedly.
How to Wash It Safely
Cold water, gentle cycle, and lay flat or hang to dry. This preserves both size and stretch recovery far longer than machine drying.
If It Already Shrunk
A brief soak in lukewarm water with a small amount of hair conditioner can relax the fibers enough to gently stretch it back into shape while damp.
