Fact--and not just because it dirties your pillowcase. Sleeping with cosmetics on can clog pores, cause zits and irritate the skin. When makeup stays on too long, it also blocks "the natural exfoliative process of shedding skin," which can leave your skin looking dull, says Dr. Robin Ashinoff, director of cosmetic dermatology at Hackensack University Medical Center in New Jersey.
Dermatologists recommend taking a few minutes each evening to adequately cleanse your skin, especially if you're acne-prone. It's not just makeup that you want to wash off. Skin is also exposed during the day to pollution and oils. Cleansing the face helps prevent the back-up of sebum--the oily stuff that the pore produces, according to Dr. Charles Zugerman, associate clinical professor of dermatology at Northwestern University.
Wash off eye makeup, too. Mascara makes eyelashes firm and inflexible. So if you rub your eyes when you sleep, you'll break or pull them easily. Many sparkly eye shadows contain "little crystals and pieces of sand," which can irritate the eye, says Dr. Vesna Petronic-Rosic, assistant professor of dermatology at the University of Chicago. And shadow dries out the skin on your lid if you leave it on overnight. "It's like a sponge sucking everything out," says Petronic-Rosic. If makeup is left on the eyes, it can clog the glands and cause inflammation.
To remove makeup, use a gentle cleansing bar or a liquid skin cleanser and water. Some good, affordable brands include Purpose, Cetaphil (if you have oily skin) or Basis (if you have dry skin). Avoid harsh facial scrubs, which contain little pieces of minerals or sand that can cause tiny scratches on the surface of the skin, says Petronic-Rosic. Consider using a gentle cleanser at bedtime and then just rinsing with water in the morning to prevent skin from drying out in the winter.
Finally, remember to apply a "bland, mild moisturizer," says Petronic-Rosic. At night, you don't need one with sunscreen since those chemicals can get into your eyes. Especially if you have sensitive skin, skip fragrance-containing creams since they can irritate or cause an allergic reaction. A good moisturizing cream will replace the barrier against the environment that you've washed away. And, unlike makeup, it won't stain your pillow.