Dihydrotestosterone (DHT), a derivative of the male hormone testosterone, is the enemy of hair follicles on your head. Simply put, under certain conditions DHT kills hair follicles. This simple action is at the root of many kinds of hair loss, so we'll address it first.
Androgenic alopecia, commonly called female pattern baldness, was only partially understood until the last few decades. For many years, scientists thought that androgenetic alopecia was caused by the predominance of the male sex hormone, testosterone, which women also have in trace amounts under normal conditions. While testosterone is at the core of the balding process, DHT is thought to be the main culprit.
Testosterone converts to DHT with the aid of the enzyme Type II 5-alpha reductase, which is held in a hair follicle's oil glands. Scientists now believe that the amount of circulating testosterone isn't the problem, but rather the level of DHT binding to receptors in scalp follicles. DHT shrinks hair follicles, making it impossible for healthy hair to survive. The hormonal process of testosterone converting to DHT, which then harms hair follicles, happens in both men and women.
Under normal conditions, women have a minute fraction of the level of testosterone that men have, but even a lower level can cause DHT-triggered hair loss in women. Even if DHT levels are within what doctors consider "normal" on a blood test, they may be high enough to cause a problems in women depending on their body chemistry.
