Just because you're out cold doesn't mean your skin is off the clock. In fact, the hours you're sleeping may be the best time to help your skin look its best. "When asleep, your metabolic rate is lower, so you're not producing as many skin-damaging free radicals. Plus, you're not exposed to environmental pollutants or UV light that can harm the skin," explains Mary Lupo, M.D., a New Orleans–based dermatologist. "Because your body doesn't have to work at skin protection overnight, it can instead focus on repairing the damage done throughout the day," she says. So any products you use will be that much more effective at hydrating, reducing fine lines and wrinkles, and brightening. Take advantage of the epidermal downtime with these easy tips to make you a sleeping beauty.