A study by the National Institute of Health found that increased cortisol levels resulted in hair loss as the hair follicles remained in an extended resting phase. Sleep deprivation causes an increase in cortisol, the steroid hormone made by your adrenal glands that helps the body respond to stress, fight infections, and regulate blood sugar, meaning that not getting at least seven hours of sleep each night could result in damaging impacts to your hairline.

Dr Balwi, leading hair surgeon at Elithair, the world’s largest hair transplant clinic, shares why sleep is important for healthy hair growth, how sleep deprivation can cause hair loss and how to identify whether sleep deprivation is impacting your hair health.

Sleep promotes hair growth

Getting enough sleep is vital for hair health as sleep supports the repair and regeneration processes, which are crucial for hair follicle growth. Sleep is also important for managing hormones required in the hair growth cycle. Adequate sleep prevents a rise in cortisol levels. However, too much cortisol can prematurely put the hair follicles into the resting phase, subsequently leading to hair shedding. 

There are hormones released during sleep which help to support hair growth:

Melatonin

Melatonin can stimulate hair follicles by promoting the growth (anagen) phase of the hair cycle and extending the duration of this phase. During the anagen phase, cells in the hair follicle divide quickly, leading to new and healthy hair growth. This only happens when melatonin levels are sufficient.

It also has antioxidant properties, which help protect cells from damage caused by environmental factors, which can be beneficial in preventing hair loss.  

Oestrogen

This is a key hormone in the hair growth cycle, especially in the hair growth (anagen) phase. Higher levels of oestrogen mean a longer anagen phase and more hair growth.

Oestrogen is also beneficial for scalp health as it improves blood flow to the scalp and helps to nourish hair follicles, promoting healthy hair growth. 

Sleep deprivation increases stress hormones 

Sleep deprivation causes increased cortisol levels, which can disrupt the body’s normal hair growth cycle. Not only does this lead to increased hair shedding and thinning, but excess cortisol levels can promote inflammation, which may damage hair follicles and prevent the production of healthy hair. 

When cortisol levels increase suddenly, the body registers the stress by sending nutrients to essential functions, like organs, over non-essential functions like hair growth. Without sufficient nutrients, an increase in this stress hormone can cause conditions like “telogen effluvium”. Telogen effluvium is a temporary form of hair loss that occurs when hair follicles enter the resting (telogen) phase of the hair growth cycle.

When you don’t get enough sleep, the process of androgen regulation does not process sufficiently. This is where oestrogen, which is released during sleep, helps to counteract the effects of androgens (like testosterone), which can contribute to hair thinning and hair loss. Oestrogen helps balance androgen levels and therefore reduces hair loss. If you do not get enough sleep, androgen regulation doesn’t happen properly, which can lead to androgenetic alopecia. Adults are recommended to have between 7–9 hours of undisturbed sleep each night, with less than seven hours being considered too little sleep for good health. 

Chronic sleep deprivation can decrease testosterone production. People who consistently get less sleep experience reduced testosterone levels. This is because when cortisol levels increase, it can inhibit the production of testosterone. While testosterone levels play a complex part in the hair growth cycle, adequate testosterone is essential for overall hair health, and this if a person’s sleep is lacking.

Is sleep deprivation causing my hair loss?

There are a few signs to look out for which may indicate that sleep deprivation is the cause of your hair loss, these include:

• No regrowth around the hairline 
• Sudden excess shedding or thinning of the hair 
• Weaker hair strands 

Tips for getting a good night’s sleep

Getting at least seven hours of sleep a day is essential for optimum health and there are some day-to-day changes you can make to improve your quality of sleep:

• Avoid using your phone before bed; instead, read or listen to a podcast. 
• Implement routine into your day, waking up and going to bed at the same time daily.
• Limit your caffeine intake.
• Stay active during the day.
• Create a nice sleeping environment.
• Avoid afternoon napping, as this could damage your nighttime sleep schedule.