Chemical basis for the cause of Female Hair Loss

The number and distribution of androgen receptors in the hair follicles, the enzymes 5 alpha reductase type I and II, and the local concentrations of dihyrotestosterone around hair follicles are the factors which are responsible for Male Androgenetic Alopecia. It is presumed that in women there are additional factors which come into play such as the concentration of Cytochrome P-450-aromatase near hair follicles as well as the distribution of androgen receptor proteins. The cytochrome enzyme metabolizes androgens to estrogens, and modifies the ratio of androgens to estrogens by having a protective role by antagonizing the effects of androgens.

Differing concentrations of androgen metabolizing enzymes and androgen receptors have been identified in hair follicles from women compared to men. The concentration of Cytochrome P-450-aromatase is six times higher in women's frontal hair follicles compared to men's frontal hair follicles. Women also have around 3 times less alpha-5-reductase type I or type II enzyme in their frontal hair follicles compared to men. Conversely, androgen receptor content in frontal hair follicles from men are 40% higher than for hair follicles from women. These differences between men and women most likely account for the overt clinical differences in patterns of hair loss.