Testosterone can cause hair growth, but not where you want it: on your head. Testosterone, which is an androgen, is a male hormone but women have it, too. It serves many functions, including keeping men and women sexually frisky. But when it comes to hair, testosterone--with a little help from DHT (dihydrotestosterone)--can cause problems. However, the impact of testosterone on hair depends on if you are a young man or an older one. In the case of women, it depends on how much testosterone you are producing.
If a woman is producing too many male hormones (androgens, including testosterone), this can result in hirsutism--excessive hair growth in women. Hair can sprout up all over the body and can be thick. Maria New, chairwoman of pediatrics and chief of endocrinology at Cornell Medical Center in New York City, explains that if an individual's hair follicles are hypersensitive to androgens--even if the androgen level is normal--this can still cause hirsutism.
In Combination With ...
If extreme hair growth pops up in a woman and this is combined with acne, lack of menstruation or irregular periods, a doctor should be consulted. It could indicate other serious problems.
Loss of Hair on Your Head
Too much testosterone can cause the hair on a woman's head to thin and even fall out. So while testosterone may make the hair on your face and legs grow, it's not going to benefit your scalp.
In male adolescents, testosterone and DHT stimulate hair growth on the face, pubic area, scalp and under the arms. Later in life, these exact hormones may prompt the hair follicles on a man's head to shrink. When a man experiences male pattern baldness, it appears that the hair follicles on his head have an extreme response and sensitivity to DHT. The follicles get broken to the point that they are no longer capable of producing hair.
Types of Body Hair
According to Wdxcyber.com (see References), there are two types of body hair. Terminal hairs are pigmented, long and coarse and are responsive to hormonal influences. Vellus hairs are non-pigmented, short fine hair that do not respond to hormones. High levels of androgen can create even thicker and heavier terminal hairs on a woman's body and sometimes manage to convert vellus hair into terminal hair.
Low Estrogen Levels
If a woman's estrogen levels are low, this allows testosterone to pick up speed and stimulate hair growth on the woman's body. DHT, the more potent form of androgen, can further stimulate body hair growth as well as acne.