Sleep and hair: what rest changes

Poor sleep leaves visible marks on the face, but hair may feel it too. The honest answer is this: there are no studies showing that sleeping little, on its own, causes hair loss in people. But several pieces fit together. The hair follicle has its own biological "clock", synchronised with day and night. Poor sleep goes hand in hand with stress, which is a known trigger of hair loss. And sleep disorders are associated with a higher risk of alopecia areata.

In practice, sleeping well is one of the foundations for hair to recover after a difficult period, and for reducing new episodes of shedding. In this guide we explain what is known, what melatonin can and cannot do, how to sleep better with evidence-based strategies and how to protect your hair during the night.

How much we should sleep

The American Academy of Sleep Medicine and the Sleep Research Society recommend that adults sleep at least 7 hours a night, regularly, to promote health (Watson et al., 2015). Habitually sleeping less than 7 hours is associated with more health problems, including weight gain, diabetes, high blood pressure, depression and reduced immunity.

It is not only about quantity:

• Regularity: go to bed and get up at the same time, including at weekends.
• Continuity: waking up many times fragments sleep, even if the total seems sufficient.
• Quality: feeling rested on waking is a good indicator.

What happens while we sleep

During sleep, the body regulates several hormones that matter for skin and hair:

• cortisol, the stress hormone, falls at night and rises in the morning; short or fragmented sleep disrupts this rhythm;
• growth hormone is released mainly during deep sleep;
• melatonin, produced in the dark, signals to the body that it is night and also acts on the skin;
• the immune system and cell repair processes follow a day-and-night rhythm.

What is known about sleep and hair

The follicle has its own clock

A study published in PLoS Genetics showed that circadian clock genes, which regulate the 24-hour rhythm, are active in the hair follicle and follow the hair cycle. In mice lacking one of these genes (Bmal1), entry into the hair growth phase was clearly delayed, because of a block in cell division (Lin et al., 2009). The cycle did eventually move forward, but later.

This suggests that the body's "clock" influences when the follicle starts to grow. It has not yet been shown whether irregular sleep or shift work has the same effect on human hair.

Sleep disorders and alopecia areata

A large population study in Taiwan, with more than 93,000 people with sleep disorders and more than 5,600 with alopecia areata, found an association in both directions (Dai et al., 2020):

This is an observational study, which shows an association and does not prove cause. One possible explanation is that poor sleep alters the immune system and the stress axis; another is that anxiety caused by hair loss impairs sleep.

Sleep, stress and telogen effluvium

Poor sleep and stress feed each other. Intense stress is a known trigger of telogen effluvium, the diffuse shedding that appears 2 to 4 months after a "shock". In mice, the stress hormone put follicles on pause (Choi et al., 2021). Here, sleep works mostly as part of the stress picture, rather than as an isolated cause. We explain this mechanism in Stress and hair loss: what is known.

Sleep and habits

People who sleep little tend to crave high-calorie foods, skip breakfast, exercise less and consume more caffeine and alcohol. Taken together, these habits also weigh on the hair.

In summary

• Direct evidence that sleeping little makes hair fall out in people is limited.
• There is a good biological basis and consistent associations that make sleep a plausible and relevant factor.
• Sleeping well has proven benefits for health in general, so it is worthwhile regardless of hair.

Melatonin and hair: what the studies say

Melatonin is known as the "sleep hormone", but it is also produced in, and acts on, the skin and the hair follicle. That is why it has been studied for hair loss, especially when applied directly to the scalp.

Topical melatonin

In a randomised, double-blind trial with 40 women with diffuse hair loss or androgenetic alopecia, daily application of a 0.1% melatonin solution for 6 months increased the percentage of hairs in the growth phase compared with placebo, in some areas of the scalp (Fischer et al., 2004). Blood melatonin levels stayed within the normal range.

How to read this result:

• it is a small, pilot study;
• the effect was measured in the percentage of growing hairs, not in density or in how the hair looks;
• significant results appeared only in some areas and some subgroups;
• it is not a first-line treatment in the European guidelines for androgenetic alopecia.

Melatonin tablets for sleeping

There is no evidence that taking oral melatonin makes hair grow. For insomnia, the 2023 European guideline does not recommend immediate-release melatonin, the best-selling kind, and accepts prolonged-release melatonin only in adults aged 55 and over, for up to 3 months (Riemann et al., 2023). Before taking it, talk to your doctor, especially if you take other medicines.

When the sleep problem has another cause

Some conditions affect sleep and hair at the same time. They are worth considering when there is persistent tiredness and hair loss:

• Thyroid disease. Hyperthyroidism causes insomnia, anxiety and palpitations; hypothyroidism causes drowsiness and tiredness. Both can cause diffuse hair loss.
• Iron deficiency. It causes tiredness and is associated with restless legs, which disturb sleep. Low ferritin is also associated with hair loss in women.
• Sleep apnoea. Loud snoring, pauses in breathing noticed by whoever sleeps next to you, daytime sleepiness and morning headaches. In the Taiwan study, it was associated with a higher risk of alopecia areata.
• Menopause. Hot flushes and night sweats fragment sleep, and hormonal changes affect hair. See Menopause and hair loss: what is known.
• Postpartum. Interrupted nights add to the normal postpartum shedding. See Hair loss after childbirth.
• Anxiety and depression. They affect sleep and are associated with several forms of hair loss.

A blood count, ferritin and TSH help clarify many of these situations. See Blood tests for hair loss: what to ask for.

How to sleep better

For people with persistent insomnia

The European insomnia guideline, updated in 2023, recommends cognitive behavioural therapy for insomnia (CBT-I) as the first treatment, which can be done in person or through supervised digital programmes. The most effective components are sleep restriction and stimulus control. "Sleep hygiene" advice on its own is not considered effective for treating chronic insomnia (Riemann et al., 2023). Medicines are kept for when CBT-I is not enough, and as a rule for a short time.

Habits that help day to day

Even though they do not treat established insomnia, these habits help protect sleep:

1. Regular times for going to bed and for waking up, every day.
2. Natural light in the morning, in the first minutes after waking; it helps set the biological clock.
3. Caffeine only until early afternoon.
4. Alcohol in moderation: it helps you fall asleep, but fragments sleep in the second half of the night.
5. A light dinner, at least 2 to 3 hours before bed.
6. Regular exercise, preferably not in the hours immediately before sleep.
7. A dark, quiet and cool bedroom.
8. Screens away in the last hour before bed, especially stimulating content.
9. The bed is for sleeping. If you do not fall asleep in about 20 minutes, get up, do something calm in low light and go back when you feel sleepy.
10. A wind-down routine: a warm bath, reading, slow breathing.

Shift work

People who work shifts often have a disrupted biological clock. It helps to protect a dark, quiet block of sleep, keep times as regular as possible within each shift, and take particular care with diet and stress.

Caring for your hair at night

Besides sleep itself, what happens to hair during the night can cause breakage, which is often mistaken for hair loss.

• Satin or silk pillowcase. It reduces friction and tangling, especially in long, curly or weakened hair. It does not treat hair loss, but it may reduce breakage.
• Tie hair up loosely. A loose braid or a high, loose bun, with a soft hair tie or fabric scrunchie. Avoid tight ponytails and hair ties with metal: repeated traction can cause traction alopecia.
• Avoid sleeping with very wet hair. Wet hair is more elastic and fragile, and breaks more easily with friction. Prolonged dampness may also encourage dandruff in people prone to it. Dry at least the roots before going to bed.
• Do not sleep with extensions or very tight braids without loosening or protecting them.
• Light night-time products. A little leave-in conditioner on the ends can help dry hair; avoid applying heavy oils to the scalp if you tend to have an oily scalp or seborrhoeic dermatitis.

If you notice many hairs on your pillow every morning for weeks, it may be true hair loss and not just breakage. In that case, an assessment is worthwhile.

When to seek a medical assessment

For sleep, talk to your family doctor if:

For your hair, book an appointment if:

At Luxmed, the Hair Medicine consultation assesses the cause of hair loss with trichoscopy and, when indicated, blood tests, and takes factors such as sleep, stress and diet into account in the treatment plan.

This article is for information only and does not replace a medical consultation.

Frequently asked questions