Beauty sleep: what a short night really does to your face

In 2010 the medical journal BMJ (in its Christmas issue) published a study called “Beauty sleep”. It was a real experiment. (BMJ 2010 — Beauty sleep (PMC))

This article explains research; it is not cosmetic or health advice.

What the “Beauty sleep” experiment showed

• Researchers photographed 23 healthy young adults (aged 18–31) after a normal night (eight hours of sleep) and after 31 hours without sleep, following a shortened night. (BMJ 2010 — Beauty sleep (PMC))
• 65 untrained observers rated the photos in random order: sleep-deprived people looked less healthy, less attractive and more tired to them. (BMJ 2010 — Beauty sleep (PMC))

What people notice

• In a 2013 study, 40 observers rated photos of 10 people after normal sleep and after 31 hours without sleep. After the sleepless night they saw more hanging eyelids, redder and more swollen eyes, darker circles under the eyes, paler skin, more fine lines around the eyes and droopier corners of the mouth. (Sleep 2013 — Cues of Fatigue (PMC))
• Sleep-deprived faces also looked sadder; rash or eczema, by contrast, did not change. (Sleep 2013 — Cues of Fatigue (PMC))

A few short nights are enough

• In another study (2017), 25 people were photographed after two days of restricted sleep and after normal sleep. 122 raters saw them as less attractive, less healthy and sleepier after the short nights — and were less inclined to socialise with them. (R Soc Open Sci 2017 (PMC))
• Perceived trustworthiness did not differ. (R Soc Open Sci 2017 (PMC))

Why this might be

1. The studies did not measure the cause, only how a face comes across to others.
2. Sleep in general, according to the US NHLBI, supports the brain and physical health; deep sleep triggers the release of a hormone that, in adults too, helps repair cells and tissues. That does not mean this particular process explains dark circles. (NHLBI — How Sleep Affects Your Health)

Where the limits are

• People were photographed without makeup and with a neutral expression; in everyday life, makeup, lighting and movement change the impression. (Sleep 2013 — Cues of Fatigue (PMC))
• Samples were small, and the authors themselves note the results may not generalise to other groups and settings. (R Soc Open Sci 2017 (PMC))
• The research rated impressions, not long-term skin health — no cream or “night routine” follows from it.

What to take from it

• Adults usually need about 7 to 9 hours of sleep. If you have slept badly for months or it is affecting your day, see a GP. (NHS — Insomnia)
• This AI health check is not a medical review. This article is not medical advice.

Takeaways

1. Beauty sleep really has been tested scientifically.
2. After a sleepless night we look more tired and less healthy to others.
3. People mainly notice the eyes, the skin and the corners of the mouth.
4. The studies are small and measure impressions, not skin health.
5. The best “cosmetic” is regular, sufficient sleep.

A short night can be read on your face — just one more rather nice reason to give yourself the sleep you need.