Why does skin shrivel up when you stay in bath water too long?

 It may seem weird to you that your skin can come become dry and wrinkly when you’re sitting up to your neck in the bath water, but it works like this. Soapy water, especially, robs your skin of its protective coating of oil. This allows water inside your skin to slowly ooze out into the bath water, so your skin is actually drying from the inside out. When your skin has lost too much water, some of its cells collapse, forming wrinkles.