Melatonin is a naturally occurring molecule produced physiologically by the body. It maintains and regulates the sleep-wake cycle, so much to be used as a remedy for insomnia and jet lag.
If taken for a long time, melatonin can generate other positive effects on the body. One of the most interesting is related to hair growth.
Recent studies on melatonin effectiveness against hair thinning are not very many and do not clear up the mechanism of action of the molecule. However, they have highlighted how the molecule can stimulate hair growth.
Melatonin and hair growth.
To understand how melatonin can prevent thinning hair, it is important to understand how the hair growth cycle works, and why with age there is hair loss.
Hair is in all respect a body hair, with a somewhat different structure than the other body hair but with a virtually identical base. It has in fact a hair stem within the hair follicle, and part protruding outside. The hair does not remain in place forever: it dies as a result of hair stem cell apoptosis. Hair has then its own life-cycle stage.
Once the hair has fallen, the follicle cells begin to synthesize a new one, which grows, and replaces the previous one. This process, as long as it is regular, avoids the occurrence of baldness.
Melatonin acts on the hair follicle, at the level of which specific receptors are present, particularly in animals. Here the hormone regulates the sleep-wake cycle and also a series of changes related to the photoperiod; both mammals and birds, according to the lengthening and shortening of the days, put in place the mechanisms of “molt”, which consist in the hair loss (or feathers, for the birds) and in their subsequent re-growth.
In particular, darkness leads a more intense growth of skin appendages. Melatonin produced by ambient light and perceived through the eyes, stimulates sleep at night and, in a so quickly manner, body hair growth throughout the period. During winter, with shorter days and the drop in temperatures, animals need to protect themselves from cold. In this period, melatonin is produced for several hours a day and consequently the hair growth is stimulated, too.
In animals, this phenomenon has been thoroughly investigated, while in humans the natural variant is more complex to be studied. In fact, even if human photoperiod declines, the electric light allows us to live days almost always equal and therefore melatonin production does not change throughout the year.
Melatonin promotes hair re-growth.
The first single blind trial study which demonstrated the effectiveness of melatonin on hair re-growth has made use of a melatonin supplement, administered for several weeks since the effect on the hair stem should be steady and continuous. The outcome of the research was positive: the difference of regrowth in patients who received melatonin (not placebo) was statistically significant.
Melatonin has therefore absolutely a positive effect on hair re-growth. However, further studies have to be carried out to understand the mechanism of action and when it is really effective on hair thinning, given that the causes leading to baldness are different. The subjects of the study were affected by alopecia, and this leads to hope that melatonin can be effective in all cases of thinning. However, this hypothesis has to be supported by the ratio of data.
Since taking melatonin has always effects on the sleep-wake cycle, it should to be taken in adequate doses and only in the evening so to avoid the risk to be sleepy during the day.