Your skin cells are regenerating
George Rudy/shutterstockWe all have a good idea of how sleep affects the body, but few of us know that skin cells go into makeover mode while we snooze. Several studies suggest that the magic happens between 11 and midnight. "That's when cell mitosis—cell division that renews and repairs skin—is at its peak, whether you're asleep or not," says New York-based dermatologist Dennis Gross, MD. "This is when cells need nutrients the most, and when their anti-aging benefits have maximum impact."
Your skin is more receptive to certain products
goodluz/shutterstockDuring renewal mode is when you'll get maximum impact from your anti-aging ingredients—they're the building blocks your skin needs for all the heavy lifting its doing. "Put the heavy hitters on at night, like retinols and glycolic acid," says Mona Gohara, MD, associate clinical professor of dermatology at Yale School of Medicine. (Applying these skin care products in the p.m. will help you get gorgeous overnight.) Another reason to apply retinols at night is that sunlight can break down its active ingredients, causing irritation, and also make you more sensitive to sun damage. To minimize the risk of irritation, Dr. Gohara suggests alternating retinol and glycolic products, and always make sure you apply sunscreen in the morning. (Helpful hint: Mornings are great time to apply a vitamin C serum to help protect your skin from free radical elements during the day.)
Your skin loses moisture
GreenArt/shutterstockSkin sebum excretion peaks at midday, and there is less sebum (oil) production at night, according to Sonoa Au, MD, of Advanced Dermatology, P.C., who is based in Brooklyn. Overnight, when you don't have a protective layer of natural oils on your skin, you lose more water. Losing water from the skin is called trans epidermal water loss, and it happens toward the end of the day and into the night. It's important to replenish the water loss with moisturizers overnight, Dr. Au suggests. These are dermatologists' golden rules for using moisturizer.
Your skin temperature changes
Pan Xunbin/shutterstockWhen you sleep, your skin becomes slightly hotter and slightly more acidic, says Dr. Au. "Those factors contribute to slightly drier skin. That's why dermatologists often recommend putting on a heavier cream at night, but it depends on your skin type." If you have oily skin, she adds, you don't want to put on something that's too thick because it could cause acne or cysts. Here's what your skin care routine should look like if you have oily skin.
Content continues below ad
You're giving skin a break from stress
PhotoMediaGroup/shutterstockWhen you get quality sleep, you're not facing the things that cause cortisol (the stress hormone) levels to surge during the day. That also means that if you short yourself sleep this week, it's going to show up on your face. "It's important to respect the sleep-beauty connection," says Dr. Gohara. "Not sleeping increases your cortisol levels and puts your skin in a pro-inflammatory state." Poor sleep will cause your skin looks sullen, and you may experience puffiness around the eyes if you're retaining water. If you're not sleeping well, these are the secrets to better sleep that doctors want you to know.
You can protect yourself from breakouts
Loginova Elena/shutterstockStress can mess with the protective outer layer of skin that keeps moisture in and bad stuff like bacteria out, according to the results of a recent animal study. "If you're under a lot of stress, it can cause inflammation, which can lead to get acne," says Dr. Au. "That's the association between constant stress and the reaction of your skin," she says. So when you're in a calm resting state and sleeping, your body isn't experiencing those inflammatory fluctuations that may lead to breakouts. Here are other sneaky reasons you're having an acne breakout.
You're giving your skin an environmental break
gpointstudio/shutterstockThere's a reason you don't have to wear sunscreen after dark. "At night, there's no UV damage, no environmental stresses, pollutions, no cigarette smoke, no big changes in temperature, and you're not wearing makeup," says Dr. Au. "All of these things happening at night mean your skin has more time to rest and rejuvenate." During the day, it's essential to wear a good quality sunscreen to minimize environmental damage. These are the sunscreens dermatologists use on themselves.
There's no sunlight to degrade your sun-spot creams
Albina Glisic/shutterstockWhether you're applying bleaching creams (hydroquinone) alone or with retinoids (tretinoin) to fade dark spots or brown spots on the skin, make sure you're doing that before you go to bed, suggests Dr. Au. During the day, you're in the sun, UV light causes an increase in melanin production, which results in pigment changes and darker color, counteracting what the products are designed to do. Check out dermatologists' advice for fading age spots.
Content continues below ad
You could cause creases on your face
KieferPix/shutterstockIf you sleep on your side, that is. "Sleep position is important," Dr. Gohara says. Sleep on your back to the best of your ability to avoid getting creases on one side of your face. Make sure your head is elevated too so excess fluid has a chance to drain, and you don't wake up looking puffy. Don't miss a day in the life of your skin to better understand how to take care of it.