Beauty sleep. It’s a phrase you hear often and, as far as your complexion is concerned, has some merit to it. Just think about how your skin retaliates in the form of dark circles, prominent fine lines, and overall dullness after pulling an all-nighter. On the flip side, think about how your face looks after a full night’s rest — refreshed and glowing. This begs the questions: How do the nighttime skin care products you slather on as part of your pre-bedtime routine actually function when you sleep? And is there a benefit to using some ingredients over others at night?
The truth is, your skin is always hard at work, and using products that support its respective functions is critical. “During the day, the skin acts as a protective barrier, defending against free radicals by producing antioxidants and using melanin to shield against UV rays,” says Dr. Jody A. Levine, M.D., board-certified dermatologist and director of dermatology at Plastic Surgery and Dermatology of NYC. “At night, the skin repairs any damage that was caused during the day. This shift is facilitated by changes in our body's circadian rhythm, allowing skin cells to work more effectively on regeneration.” Below, TZR spoke with dermatologists to learn about how the skin functions at night as well as how to tailor the perfect evening skin care routine.
What Happens To Your Skin When You Sleep
When you sleep, your skin transitions from its daytime defense mode to a repair and regeneration mode, says Dr. Ann Mazor Reed, M.D., a board-certified dermatologist at Rendon Center in Florida. The skin goes through several shifts overnight, one of them being an increase in blood flow, which plays a crucial role in maintaining the health and appearance of your complexion by delivering more nutrients and oxygen to the skin. In the same token, poor blood flow and circulation can lead to a dullness, slower wound healing, and compromised skin barrier function. To draw the comparison of how this compares to your skin’s daytime function, Dr. Bertha Baum, M.D., a board-certified dermatologist at Aventura Dermatology, says that when you’re awake, your body is in “fight or flight mode” the majority of the time, but at night, you enter “rest and digest mode” where the blood is able to supply more areas that are usually forgotten.
Your skin also gets more acidic when you sleep. This shift towards a lower pH can help maintain hydration by supporting the barrier function, says Dr. Baum, which means the skin is better able to trap moisture and keep damaging external aggressors out. Acidic skin can also help regulate oil production and assist with shedding of dead skin cells. Using products that aim to keep the barrier healthy can support the skin’s natural function during the night.
Another thing your skin does during sleep is address UV damage through a process Dr. Levine says is called DNA repair. “[The skin] can more effectively correct the damage caused by UV radiation at night because it's not simultaneously exposed to new UV rays as it is during the day,” she says. In addition, skin cells also regenerate more quickly at night, and collagen, the protein responsible for maintaining volume and elasticity, is produced during this restoration period.
Finally, Dr. Reed tells TZR that the skin's ability to absorb skin care products may be enhanced at night, “making it an ideal time to apply treatments like moisturizers, serums, and retinoids that promote skin repair and rejuvenation.” Nighttime is also a period of reduced exposure to external environmental stressors such as UV radiation, pollution, and temperature extremes, which allows the skin to prioritize repair.
Your Nighttime Skin Care Routine
The first step in your nighttime routine should be to get enough quality sleep, which is crucial for ensuring that the skin receives the necessary support for repair, regeneration, and a healthy appearance, says Dr. Reed. Next, you should consider the ingredients in the topical products you use, focusing on ones that will support your skin’s natural nighttime function. Ceramides are one such ingredient. “Ceramides are a type of lipid that are found on the stratum corneum, which is the most superficial layer of the skin,” says Dr. Baum. “[They] are very important for skin barrier and health and can indirectly support collagen production and skin rejuvenation.”
Hyaluronic acid is another well-loved ingredient for nighttime — especially if your skin leans dry. “Applying hyaluronic acid-rich products before bedtime can help optimize skin hydration during the night when the skin is naturally engaged in repair and regeneration processes,” explains Dr. Baum. The ingredient forms a hydrating barrier on the skin's surface, helping to lock in moisture, which is especially important during sleep when the skin's barrier is working hard to prevent trans epidermal water loss (TEWL), says. Dr. Reed. The result is a plumper, smoother complexion come morning.
Lastly, retinol, a form of vitamin A, can help address a variety of skin concerns while you sleep. The ingredient should be reserved as part of your nighttime skin care routine because daytime UV rays can deactivate it. Plus, giving it a chance to work its magic while your skin is in repair mode comes with benefits. Retinol helps support your skin’s natural production of collagen at night by stimulating collagen synthesis, resulting in a smoother and firmer complexion. It can also can be effective at fading discoloration, such as dark spots, age spots, and post-inflammatory hyperpigmentation from acne, says Dr. Reed.
The bottom line? The ingredients you use at specific times of day are equally important as the types of products that make up your routines. Plan accordingly.