Minoxidil, sold under the trade name Rogaine in the U. S. Is one of the first line treatments for hair loss from male pattern baldness (androgenic alopecia) in both men and women. It is currently sold without a prescription as a topical solution that is applied directly to the scalp in an effort to stop hair loss and promote regrowth of hair. However, this was not always the case.

When minoxidil was first introduced, it was sold in tablet form as a prescription blood pressure medication. It is, in fact, one of the strongest antihypertensives available and only prescribed in cases of extremely malignant high blood pressure that do not respond to other medications. An interesting side effect was noted in patients who took minoxidil tablets. They tended to see an increase in growth of body hair.

Experiments were conducted that showed that a topical application of the drug to the scalp could stop hair loss as a result of male pattern baldness and, in some cases, reverse the process. It was determined that a topical solution of 5 percent was adequate for men experiencing hair loss and a solution containing only 2 percent would suffice for women.

Originally, even the topical form of the drug was sold by prescription only. Following a period of several years and a variety of research studies, it was shown to be safe enough when the directions were followed to make it available over the counter without a prescription.

While the medical community still does not understand the mechanism of function that makes this drug work to stop hair loss, there is sufficient medical evidence showing that it does affect the hair follicles in some way.

Oddly, one possible side effect of use of minoxidil is hair loss. This only occurs in rare instances, however, and is almost always followed by a period of regrowth. The drug generally continues to be effective as long as it is used regularly, but stops working and hair loss resumes if treatments are ceased.