Hair loss can be a traumatic situation. The amount of money spent on this issue, which amounts to over $1 Billion per year, demonstrates the value we place on our hair.
Briefly, let’s look at how hair grows. The hair follicles, which are below the skin, are constantly undergoing cyclical rounds or phases: the telogen phase is a resting phase with no growth, the anagen phase, which is rapid growth, and the catagen phase, which is degeneration.
Just as in other conditions, there are multiple reasons why people lose hair, but it usually boils down to the diet, stress levels, or hormone issues combined with genetic factors. We will focus on the hormone aspect, but other factors should not be ignored. That diet affects hair can be surprising to some people, but lack of vitamins (like vitamin D, biotin and others), minerals and especially protein directly impact hair formation by decreasing the number of hair follicles. And stress is another often overlooked factor. High cortisol levels from stress cause the hair follicles to go into the resting phase (telogen phase) and sometime later, that hair will fall out.
Other sex hormones have an effect on the condition of hair, but we will concentrate on testosterone. Until the last couple of decades, it was assumed that the testosterone itself was causing hair loss, but it turns out that for scalp hair, it is not testosterone that causes the loss, but dihydrotestosterone (DHT). Testosterone in the body is converted to DHT by an enzyme called 5-alpha reductase which can be found in the prostate and testes as well as in hair follicles . DHT is more powerful than testosterone itself and will attach more effectively to receptors. It will cause a miniaturization of the follicle, a shortened duration of the anagen phase (growth), and a lengthened telogen phase (rest). All this leads to shorter hair which easily just falls out of the follicle causing the hair loss.
Another unusual aspect is that scalp hair will grow before puberty without DHT but it is required for other body hair. While not completely understood, once the person reaches puberty and testosterone rises, DHT starts being produced and hair loss begins. The rate at which this happens is determined by many factors including the genetic makeup of the individual, especially the amount of the enzyme 5-alpha reductase.
It had been theorized that male pattern baldness was a result of an individual having high levels of testosterone but as we see above that is not the case. A person can have normal or even low levels of testosterone and if they also have high levels of that enzyme they will still lose hair.
Studies have shown that early in the process there are some ways to mitigate but not stop hair loss. Of course, dietary concerns and stress should be addressed. Medications like finasteride can inhibit the 5-alpha reductase enzyme while minoxidil dilates blood vessels around the follicle.
As we see, the process of hair loss is a common, natural process in most situations. So like other things in life, we can either accept the changes or we can attempt to stop them.