The most widespread form of hair loss (androgenetic alopecia, also known as male or female pattern hair loss) is determined by age and genetics and is not preventable or curable. But there are some treatment options
Originally developed as an oral blood pressure drug, minoxidil (Rogaine and generics) stimulated hair growth as a side effect—and was then shown to produce new hair growth when applied to the skin. It is available as a 5% foam and 5% topical solution for men and a 5% foam and 2% solution for women. Minoxidil affects only the crown of the head; a receding hairline is rarely restored. New hair is usually thinner and lighter, like baby hair. And many users will not experience any significant hair growth. Be aware that it can take up to four months to see if it’s working and that if you stop using it, any new hair will fall out. Minoxidil should not be used by women who are pregnant or breastfeeding.
Finasteride (Propecia) is the same prescription drug used in higher doses (and called Proscar) to treat an enlarged prostate. Taken orally, it inhibits an enzyme that converts testosterone to dihydrotestosterone (DHT), a hormone that can cause hair follicles to shrink. The drug’s benefits are well documented, and side effects, including erectile dysfunction and loss of libido, are relatively uncommon. It works best for men who are beginning to lose hair, not those who are completely bald, and is better for hair loss on the crown than for receding hairlines. It may take at least six months to see results.
Most hair growth occurs by two years, but the drug must be taken indefinitely to maintain the benefits. If balding is due to something other than androgenetic alopecia, the drug won’t work at all. Finasteride is not approved for women with hair loss, since it causes severe birth defects in male fetuses; pregnant or potentially pregnant women should not even touch the tablets.
Though there’s no evidence of serious problems, we still hesitate to recommend Propecia. Younger men, the prime candidates, would need to take a drug that affects their hormones for the rest of their lives to maintain results—and there are no data yet to back its safety over that many years.
A possibly promising treatment for androgenetic alopecia is platelet-rich plasma (PRP) injection, done by some dermatologists. Derived from the patient’s own blood, PRP contains various growth factors that may stimulate development of hair follicles. Clinical improvements have been seen in a few studies, and the treatment appears to be safe— but it’s still in its infancy, and before-and-after photos used to promote it seem too good to be true.
Some doctors use other drugs off-label, including dutasteride, spironolactone, and oral contraceptives, to treat androgenetic alopecia. Low-level laser treatment may also help slow hair loss or help regrow hair in some people.
What about biotin supplements and special shampoos?
According to a review in Dermatology and Therapy in 2019, biotin deficiency (rare in the U.S.) can cause hair loss, but “there are no evidence-based data that supplementing biotin promotes hair growth.” MedlinePlus, from the National Institutes of Health, concurs that there is “insufficient evidence to rate the effectiveness of biotin for hair loss.” Don’t count on other dietary supplements or herbs, or on “revitalizing” shampoos, either, to make lost hair grow back. Some “volumizing” shampoos and conditioners may give the illusion of thicker hair, however.