Melatonin impacts so much more than a good snooze. Case in point: Your melatonin levels can influence just how glowing and smooth your skin is: “Melatonin is critically important for your skin and plays a significant role in skin repair from environmental exposure, UV light, stressors, pollution, and so on,” says board-certified dermatologist Keira Barr, M.D., on an episode of Clean Beauty School. Beauty sleep is very much real.