You might know of melatonin as the hormone which makes you sleepy, but research suggests it could also support hair growth and may be a treatment for androgenetic alopecia (male or female pattern hair loss).
How does melatonin play a role in hair growth?
Melatonin is best known for regulating your circadian rhythm, aka your natural 24-hour body clock that tells your body when to sleep and when to wake.
But melatonin does more than make you feel tired, it is also produced locally in the hair follicle, where it helps regulate the growth cycle. One of the key ways it does this is by activating the Wnt/βcatenin signalling pathway, a major driver of follicle development, stem cell activity, and the transition from resting (telogen) back into active growth (anagen). This pathway is essential for helping hairs stay in the growth phase for longer, giving them more time to thicken and increase in density.
Plus, melatonin is also a powerful antioxidant. This means it helps protect hair follicles from oxidative stress - damage caused by free radicals - which contributes to DNA damage, greying, and thinning over time.
What does research say about melatonin for hair regrowth?
While research is still emerging, studies so far suggest topical melatonin (a solution applied directly to the scalp) could reduce hair shedding and may be an effective treatment for androgenetic alopecia (AGA).
In an animal trial with mice, researchers used gene expression analysis to determine that melatonin increased hair regeneration by up-regulating the Wnt/β‐catenin signalling pathway in hair follicle stem cells and dermal papilla cells. This signalling pathway drives follicles from the resting phase into the growth phase, kickstarting the hair cycle again.
When looking at how melatonin might affect hair growth in humans, researchers tested it on hair follicles in organ cultures under lab settings. Low dosses appeared to stimulate hair growth, but only in the early days between days 1 and 5. A later study confirmed that melatonin had no effect on human scalp hair growth at a range of concentrations.
Clinical trials involving humans are more limited. In a small trial with 40 women with either diffuse alopecia or AGA, topical melatonin increased the percentage of hairs in the anagen (growth) phase, suggesting improved hair cycling activity in the crown region, but it did not have much influence in the frontal region of the scalp. This study would need to be repeated with more participants for a longer period to confirm results.
In a large multicentre study involving 1,891 people, after 90 days of daily topical melatonin application, participants showed a significant reduction in hair shedding. The number of people with an abnormal ‘positive’ hair pull test dropped from 61.6% to 7.8%, while those with a normal hair pull test increased from 12.2% to 61.5%, an indication that shedding reduced dramatically.
Even though the research so far shows melatonin may be beneficial, no robust, peer-reviewed clinical trials have been conducted. This means it’s hard to say with confidence how effective topical melatonin is for treating hair loss.
How does melatonin compare to proven treatments?
So far, no studies have directly compared melatonin to existing treatments like minoxidil or finasteride in a head-to-head study.
Based on research that has been conducted so far, melatonin might help reduce hair loss and promote hair growth along similar pathways to Minoxidil Spray. It’s also known to help hair stay in the growth phase for longer by lengthening the anagen phase and shortening the telogen phase. Plus, minoxidil also stimulates the WNT/βcatenin signaling pathway, which is a crucial driver of a healthy hair cycle.
However, melatonin is not known to directly impact dihydrotestosterone (DHT) levels, which is the hormone which binds to hair follicles and causes hair loss in men with androgenetic alopecia. Finasteride, on the other hand, directly lowers DHT levels which helps prevent miniaturisation.
All of our blog articles are reviewed by our Medical Director before publication.
