Dihydrotestosterone (DHT), a derivative of the male hormone testosterone is the enemy of hair follicles on the head. In short, under certain conditions DHT follicles wants dead. This simple action is at the root of many types of hair loss.
Androgenetic Alopecia, commonly known in male or female pattern baldness, is only partially understood until recent decades. For many years, scientists thought that androgenetic alopecia was caused by the predominance of the male sex hormone testosterone, which women are also in trace amounts under normal conditions. While testosterone is at the center of the balding process, DHT is thought to be the main culprit.
Testosterone converts to DHT with the help of the enzyme type II 5-alpha reductase, which is in the oil glands of a hair follicle. Scientists now believe it is the amount of circulating testosterone that causes the problem, but the level of receptor binding of DHT in the scalp follicles. DHT shrinks hair follicles, making it impossible for healthy hair to survive.
The process of hormonal conversion of testosterone to DHT, which then harms hair follicles, occurs in both men and women. Normally, women have a fraction of testosterone that men have, but even lower levels can cause hair loss in women. These levels can rise and still be within what doctors consider “normal” blood test, although they are high enough to cause a problem. This is a problem if you have the body type that is too sensitive to body chemistry, including hormones.
Hormones are cyclical. Testosterone levels in some men drop by 10 percent every decade after thirty. The female hormone levels drop dramatically during menopause and beyond. The cyclical nature of both hormones and hair is one of the reasons why hair loss can increase in the short term.