Female-pattern baldness, or androgenetic alopecia, is characterized by an excessive amount of hair loss. The hair follicles in women with this condition typically are more sensitive to the androgen dihydrotestosterone, or DHT, which causes the follicles to shrink and eventually cease producing hair. Although women often respond favorably to minoxidil, a medication that treats androgenetic alopecia, only 20 to 25 percent of affected women experience hair regrowth, according to the National Institutes of Health. If minoxidil fails to provide positive results, women can consider other treatments, such as spironolactone.
The American Hair Loss Association and the American Osteopathic College of Dermatology recommend the use of spironolactone to treat androgenetic alopecia in women. This prescription medication typically is used to treat high blood pressure, edema and hyperaldosteronism, indicates the Mayo Cliniic. However, it also can act as an antiandrogen.
An antiandrogen such as spironolactone slows the production of androgens, otherwise known as male sex hormones. In female-pattern baldness, the most important androgen to inhibit is testosterone. When testosterone comes into contact with Type II 5-alpha-reductase, an enzyme found in the oil glands of hair follicles, it is converted into DHT, which is responsible for the miniaturization of the follicles that leads to hair loss, according to the American Hair Loss Association.
The American Hair Loss Association says this isn't the only way spironolactone treats androgenetic alopecia in women. It also can keep DHT from binding to the androgenetic receptors within the follicles. Those follicles with these receptors are far more sensitive to DHT. But not all follicles have this characteristic. In women with androgenetic alopecia, they typically are found along the top of the head. Only this area of the scalp experiences hair loss.
The most obvious benefit of spironolactone treatment is lowered testosterone levels, which inevitably lowers DHT levels. With less DHT in the scalp, fewer hairs are lost. Coupled with the inability of DHT to bind to the hair follicles, this can slow the progression of hair loss and even encourage the regrowth of lost hair. The only caveat is that this treatment is most effective before menopause, states the American Osteopathic College of Dermatology.
As with any medication, there is the potential for side effects. The Mayo Clinic says spironolactone sometimes, but rarely, can cause abdominal cramping, bloody stools, diarrhea, constipation, heartburn, indigestion, decreased appetite, discharge from nipples, cloudy or dark urine, increased blood pressure, hives, itching, dizziness and increased heartbeat. Consult a doctor if you have any of these side effects.
Spironolactone does not treat male-pattern baldness. As of 2010, minoxidil and finasteride are the only two medications approved by the U.S. Food and Drug Administration for men with androgenetic alopecia.