German Philosopher, Friedrich Nietzsche’s, solid effort at Movember. (Photo Credit: Wiki Commons)
It’s November! That means it’s the annual attempt, for some, to grow hair above their lip. Whilst some can grow a Nietzsche-like moustache, others barely get fuzz. But why? What causes facial hair growth? Is it testosterone levels? Is it genetic? Is there an environmental factor? And is there anything you can do to increase, or decrease, the growth?
The human body is covered in very fine vellus hair. During puberty, an increase in androgens (e.g. testosterone) stimulates the change of some vellus hair follicles into terminal hair follicles, which produce larger, darker hairs. The areas where this occurs are called androgenic hair. As long as there is normal thyroid function and good nutrition, then androgens are the main regulator of hair growth. Average female levels of androgen are enough to cause armpit and pubic hair follicles to change from vellus to terminal, whilst average male levels of androgen are required for beard, chest and back hair to change. This level of androgens creates a permanent change in the growth at the hair follicle and a lowering of androgen below this level won’t cause a decline in growth to vellus hairs. However, changes in the amount of androgens above this level do create temporary alterations in the follicle response, i.e. the growth rate of facial hair.
Arctic explorer, Fridtjof Nansen, with his moustache. Is facial hair growth linked to testosterone levels? (Photo Credit: Wikimedia)
Is it as simple as: the more testosterone you have, the hairier you are? Not quite. Testosterone binds to androgen receptors, increasing hair growth. But for beard hair testosterone is metabolized, by an enzyme called 5α-reductase, to 5α-dihydrotestosterone (DHT). DHT binds more strongly to androgen receptors than testosterone and the binding to androgen receptors is what causes hair growth. Men with 5α-reductase type two deficiency will only have pubic and armpit hair develop at puberty. So while testosterone levels will affect beard growth, 5α-reductase activity will have a bigger impact. Follicle sensitivity also varies, between people, and even at different areas on the same person, as you get differences in gene expression within follicles at different sites. For instance, the moustache is usually the first area to grow terminal hairs, then they spread gradually over the face and neck. This process can take years – in fact peak beard might not be reached until your 30s. Androgens, especially DHT, also play a role in male pattern baldness. This is caused by the changing of terminal hair follicles on the scalp to vellus hair follicles. The better a beard you can grow, the more likely you are to go bald later in life.
Charles Darwin, lots under the chin but little on top. Is beard growth linked to baldness? (Photo credit: Wiki Commons)
Are there any other factors to facial hair growth? Both beard growth and male pattern baldness run in families. Also, Caucasian males generally have higher beard growth rates than Japanese males and higher amounts of male pattern baldness than African males. These both suggest a genetic factor. There is also a seasonal variance in the growth rate of facial hair, with the lowest rates in winter and a peak in rates at summer. The reason for this is unclear. It may be due to seasonal changes in testosterone levels, although women’s scalp hair also shows seasonal variance in growth rates and this is not due to testosterone changes. Is there anything that can be done to increase beard growth? Not really. A common myth is that shaving causes hair to thicken. Shaving makes the tip of the hair blunter, perhaps giving an impression of thickness during the start of growth, but won’t make the actual hair any thicker. If the lack of facial hair growth is due to low testosterone levels, testosterone supplements could be taken, though this isn’t advised due to the possible side effects. If the reason for low facial hair growth is due to poor nutrition, then a change in diet may help. If your beard is patchy, that may be down to youth, as it can take until your 30s to reach peak beard glory. But for many, the main reason of low beard growth will be genetic and there isn’t much that can be done to change that, just take solace in spending less money on razors.