Why Beauty Sleep Isn't Just a Myth Part II

It simply makes everything better (especially skin) the next day.

By Mollie Eastman, Sleep Advisor

Gina Mari

What Happens to Your Skin While You’re Asleep?

Needless to say, the visual outcomes we just discussed are never fun to wake up to. So, what’s going on? What is it about sleep that has such a dramatic impact on the health and appearance of our skin?

Recuperation Time

First thing’s first: sleep allows us to rest, recover, and recuperate. But, it isn’t just our brain and muscles that get some much-needed respite! Our skin does too. During the day, the skin is responsible for a number of roles, perhaps most notably, it protects us from environmental elements, like harmful pollution, wind, light, bacteria, temperature changes, and more. So, for all the functions it performs throughout the day, it becomes imperative that it goes through a period of rejuvenation. This is where an intimate relationship with sleep and skin comes into play; during sleep is when the skin has the opportunity to repair and recharge.A wealth of compelling research now points to the role of sleep in allowing our skin to repair any damage, recover from inflammation, and so on. Take the piece of research in The Academy of Sleep Medicine that we mentioned above. The authors of that study didn’t focus exclusively on skin elasticity. Instead, they were interested in the general impact of sleep restriction on appearance. While they draw their conclusions from a small sample of 24 women, it remains a useful reference point for understanding what happens to our skin under these circumstances. The authors note that: “…Sleep restriction lasting two nights can significantly affect hydration, trans-epidermal water loss, reduced extensibility and elasticity, delayed extensibility, oxidation (MDA), and acidity (pH) of facial skin.”

Phases of Detoxification, Repair, and Recovery

What exactly does the skin restoration process look like hour by hour? We can break it down into particular phases. In the hours leading up to sleep, your skin goes through a wind-down interval and is beginning to be bathed in melatonin, a master antioxidant. This time frame shifts the skin from the daytime protection mode over to preparing for the nighttime reparation mode that occurs during sleep. The next generalized phase is detoxification, which happens when the body transitions to sleep. For many in our modern society, around 11 PM to 4 AM is when the skin’s blood flow is at its highest point, and the skin cycles through its highest number of mitosis cellular divisions. During the first half of the night, we work through our highest ratio of deep sleep. At this time, Human Growth Hormone (HGH) is beginning to be secreted, which speeds up skin repair and cell regeneration. This period of repair happens from around 2 AM to 4 AM for most and it’s crucial for the health of our skin. Finally, the morning phase, for most spanning from about 4 AM onwards, is when Transepidermal Water Loss (TEWL) is at its peak. As a result of this water loss, our skin can be particularly dry during this time, and consequently, the skin barrier is more easily damaged. This skin-sensitive morning phase stands as an opportunity to prioritize nourishing the skin.

Collagen Production

The repair process that occurs during sleep is heavily related to collagen, a special protein that has a major protective function in our bodies. When it comes to skin, you can think of it as a building block that helps to prevent sagging and keep everything supple, plump, and youthful-looking. Our skin produces more collagen each night when we’re asleep, which is another reason it’s so detrimental to deprive ourselves of rest. With lower collagen levels in our system, our skin lacks the tools to stay in top condition. The wrinkles, fine lines, and sallow appearance listed above are, in large part, related to this paucity of collagen in your system.

Blood Flow

Another reason sleep is so important for skin health is because, as mentioned above, blood flow increases throughout the night. Losing sleep disrupts this process and causes various circulatory issues. Remember the dark undereye circles? They’re often a symptom of this in action. Poor blood flow causes it to pool under the eyes (4), which is super visible through the thin skin on this part of the face. This isn’t just anecdotal. An article in Medical News Today (5) goes into detail on the topic of sleep-related circulatory issues. In it, they describe a piece of research that demonstrates the role of good sleep in keeping your arteries supple, which maintains effective blood circulation as a result.

Melatonin Release

Commonly referred to as the “sleep hormone,” melatonin is a crucial component in the body’s sleep-wake cycle. It’s produced naturally by the pineal gland in our brain whenever the sun goes down and the day fades into darkness, making us feel sleepy. Production stops when we’re exposed to light (traditionally when the sun comes up), which then helps us feel more alert and ready for the day ahead. This is why so many people who struggle with their sleep run to melatonin supplements: they are aiming to elicit that treasured tired feeling. However, the role of melatonin doesn’t end there. According to Nature (6), it also “has antioxidant, anti-inflammatory, anti-apoptotic, and many other crucial properties.”And that’s where melatonin specifically affects our skin. As a powerful antioxidant, melatonin helps neutralize free radicals we encounter from harmful UV rays and pollution, turning it into “an effective anti-aging skin compound” (7).Notably, an article in the peer-reviewed journal Experimental Gerontology (8) points out that levels of melatonin secretion appear to dwindle with age, as well as with other diseases, mood disorders, and severe pain. So, if your lack of sleep is related to a drop in melatonin (which can also occur as a result of certain melatonin-lowering behaviors), your skin may also look aged, sooner.

Chronobiology & Circadian Rhythm

Everything discussed thus far in this article lives under a fascinating new branch of study known as chronobiology. Chronobiology is the science of how aspects of time impact our biology—and one vital and complex aspect of our biology is our skin. The science of “when” is precisely the area to become more familiar with in efforts to protect and care for our skin.When delving into the world of chronobiology, it’s crucial to understand that it exists to examine how particular environmental and behavioral rhythms affect our internal biological rhythms. Examples of these rhythms include circadian rhythms that operate around 24 hours, ultradian rhythms that are less than 24 hours, and infradian rhythms that are around one month. When discussing circadian rhythms, in particular, we examine the specific tasks and processes the body is going through routinely in a single day and night cycle.Our sleep-wake cycle is an example of a circadian rhythm, but how does the body know when to sleep and when to wake? Virtually every cell and organ system in our body houses tiny “clocks.” These clocks can be referred to as biorhythm and point to the varied bodily processes that happen in approximately a 24 hour period. These tiny peripheral clocks all communicate with the master clock, known as the Suprachiasmatic Nucleus (SCN) located in the brain’s hypothalamus. This master clock is the “conductor” directing actions for all of those peripheral clocks and is affected by environmental cues like light, temperature, meal-timing, and more. When these clocks all work in harmony, bodily functions are in alignment with a robust circadian rhythm. Circadian rhythm entrainment, when the body is entrained to function in a rhythmic and repeatable manner, is crucial in our efforts of getting and maintaining quality sleep to reap the benefits and avoid the negatives addressed above. When these clocks are aligned, there may be certain parts of the day when you feel more alert and focused as well as you may also anticipate other parts of the day when you feel sleepy and relaxed. That same rhythm is happening with the skin (whether you’re aware of it or not) because the skin has its very own circadian clocks to guide these functions to happen in a specific manner throughout 24 hours. However, when sleep and sleep-supporting habits and behaviors are not prioritized, those clocks can become misaligned and create a whole host of problems for both skin health as well as overall health.

Insights on Skin and Sleep

Many people discount the idea of beauty sleep as fanciful. However, there is plenty of hard science to back it up. The quality of our sleep indeed has a direct impact on our appearance. And it most notably affects our skin. If one takes the steps to improve their sleep, then it’s only a matter of time before it reflects in the look and luster of their skin.


  1. aasm.org | Study reveals the face of sleep deprivation
  2. Sleep Medicine | The impact of sleep restriction on skin parameters and facial appearance of 24 women
  3. US National Library of Medicine | Acne Severity and Sleep Quality in Adults
  4. aarp.org | How to Get Rid of Dark Circles Under Your Eyes
  5. medicalnewstoday.com | How lack of sleep harms circulation
  6. nature.com | Melatonin as a master regulator of cell death and inflammation
  7. US National Library of Medicine | Neurobiology, Pathophysiology, and Treatment of Melatonin Deficiency and Dysfunction
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