"Because it may be pretty effective in stopping the loss of hair, more so even than in regrowing hair ... then it makes sense to start taking it as early as possible," he says, noting that men can begin showing signs of common baldness as early as age 15.
Male pattern baldness is an inherited trait, which is caused when too much of the hormone dihydrotestosterone -- or DHT -- is in the blood. The DHT builds up in the scalp and damages the hair-producing follicles, which eventually die. DHT is produced when a chemical in the body converts androgen to DHT. Finasteride works by interrupting this chain of events, thereby reducing DHT production.
Interestingly, the same process is involved in both enlargement of prostates and in the development of acne.
In addition, some women also suffer from androgenetic alopecia, but finasteride is not approved for treating them. According to Whiting, testing has determined that the drug is not effective on postmenopausal women. Trials have not been done on women of childbearing age because it's already known that using an androgen-based drug on these women could result in birth defects in male babies.
Research goes on in search of better ways to save men's -- and women's -- pride: their hair. In fact, a number of companies are investigating drugs similar to finasteride, Whiting says.
"It's a very exciting field of research," he says. It's possible, he says, that if scientists can come up with different formulas to block DHT production, they could better treat and prevent baldness along with acne and enlarged prostates. However, he cautioned that successful therapy also could cause problems if used the wrong way.
The FDA approved finasteride for enlarged prostate treatment in 1992 and for treatment of baldness in late 1997.