Women who are experiencing thinning or loss of hair may benefit from a drug that blocks the effects of testosterone, according to a recent study.

Hair loss in women may be caused by an increase in activity of androgens, or male hormones, on the scalp, or by the scalp becoming more sensitive to the effects of androgens, according to experts.

In the past, researchers have attempted to determine whether drugs that block androgens may stop hair loss, however have not been successful.

In the current study of 48 women with thinning hair and elevated androgen levels, women were assigned to take either flutamide, a testosterone-suppressor drug; cyproterone acetate, an anti-androgen treatment; finasteride (Propecia), a drug used to treat hair loss in men; or no treatment for a period of one year.

Women who took the testosterone-suppressor flutamide for one year had the best results and were more likely to say that their hair regrew, had stopped thinning and had improved in overall appearance than women who had received another drug or no treatment.

However, total improvements were small with results described as being only moderate, according to researchers.

Specifically, eight of the 12 women taking flutamide said their rate of hair loss had decreased, compared with three of the 12 given cyproterone acetate and one of 12 who received finasteride.

Researchers noted that flutamide has been linked to severe liver damage, so while doses can reach 750 milligrams per day, doses in the current study were limited to 250 milligrams per day. Nonetheless, two of the 12 women taking the drug had a mild increase in liver enzymes, though it was reversible.

Prolonged treatment with flutamide may result in better, more substantial hair regrowth, however may also increase the risk of liver damage. Patients should be closely monitored for liver function while taking the drug, researchers noted.

Fertility and Sterility January 2003;79:91-95