When it comes to preventing wrinkles though, there’s less proof. “One of the things we know that happens as we age is the fibroblast cells become a little bit sleepy. The theory is the light will stimulate them into action to produce collagen, which is something we need for thicker, plumper, less wrinkly skin.” But there’s no substantial evidence to back this up, he says. And if it does work, professional sessions are far more likely to be effective as they’re stronger than the at-home masks.