Hormones are chemicals that are produced in one area of the body, travel through the bloodstream, and produce effects in another area of the body.
Androgens, the so-called male hormones, are produced, by both men and women, in the testicles, ovaries, and adrenal glands. The adrenal glands are small glands above the kidneys.
Testosterone is the most well-known androgen. At puberty, testosterone levels rise and, among other effects, cause the fine, short,”velous” or baby hair in the pubic areas and in the armpits to become coarser hair.
In the scalp, testosterone is converted, by an enzyme called “5-alpha reductase”, to a different androgen called “dihydrotestosterone (DHT).” DHT, more than any other androgen and more than estrogen, causes genetically sensitive hair to be lost. An enzyme called aromatase converts testosterone to estrogen.
In genetically sensitive hair, DHT causes each generation of hair to become progressively smaller. This process is called miniaturization. Hair goes through a life cycle, with growing, transition, and resting phases. DHT causes each generation of hair to have a shorter growing phase. It also causes each generation of hair to become more narrow and lighter in color. The miniaturized hairs get so light, fine, and short that they can’t be seen and eventually the root stops producing hairs altogether.
Most people who suffer from Androgenetic Alopecia have normal levels of circulating androgens. Conditions that lead to increased androgen levels such as
polycystic ovarian syndrome or the taking of extra androgens in the form of anabolic steroids, can lead to accelerated hair loss. There are usually other signs and symptoms if there are excessive androgen levels.
Genetics and hormones cause both Male Pattern Baldness and Female Pattern Baldness. Since some women get a male pattern and some men get a female pattern and female pattern baldness may run in some families in both women and men, some feel that there are genetic differences. Others feel the differences in the patterns can be explained by differences in the hormones alone.
There are a few reasons why there is less hair loss in women with female pattern loss than in men with male pattern loss. Women have lower levels of circulating testosterone and have lower levels of 5-alpha reductase in the scalp, especially in the crown. In addition, women have higher levels of aromatase throughout the scalp and especially in the hairline. They therefore have less circulating testosterone, more aromatase to convert that testosterone to estrogen and less 5- alpha reductase to convert testosterone to DHT. In these three ways they have lower levels of DHT in the scalp. To summarize, normal levels of your own natural androgens and especially DHT cause the progressive miniaturization and loss of your hair, when you have the genes for Androgenetic Alopecia. Most, but not all, women have lower levels than men of DHT in the scalp and often have even lower levels in the hairline and in the crown.BACK