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FDA approved Skin and Hair

Finasteride

Also called Propecia (1 mg, hair loss); Proscar (5 mg, prostate)

An FDA-approved daily pill for male pattern hair loss. It lowers DHT, the hormone that shrinks hair follicles, and stops further loss in most men who take it.

Overview

What it is

A small-molecule 5-alpha-reductase inhibitor, not a peptide. The hair-loss dose is 1 mg a day; 5 mg is used for an enlarged prostate.

How it works

The enzyme 5-alpha-reductase (type 2) turns testosterone into DHT. In men with a genetic tendency, DHT gradually shrinks scalp hair follicles. Finasteride lowers scalp and blood DHT by roughly 60 to 70 percent, which halts shrinking and lets some follicles recover.

What the research shows

In two-year placebo-controlled trials, most men taking 1 mg a day kept or regrew hair, while men on placebo continued to lose it. Five-year follow-up showed the benefit lasted with continued use. Results appear after 3 to 6 months and fade within about 12 months of stopping. Topical finasteride is used by compounding pharmacies but is not FDA approved in the U.S.

Studied for

  • Male pattern hair lossFDA approved, 1 mg
  • Enlarged prostate, BPHFDA approved, 5 mg

Safety and regulatory status

Safety and side effects

A small share of men report lower libido, erectile problems or less ejaculate; some report symptoms that continue after stopping. Depression and suicidal thoughts have been reported and were added to the label. It lowers PSA by about half, so tell your doctor before prostate screening. Women who are or may become pregnant must not handle crushed or broken tablets because it can affect a male fetus.

Regulatory status

FDA approved prescription medicine for men (Propecia, Proscar, generics). Not approved for women.

Common questions

Does it regrow hair?

Mainly it stops further loss. Many men also see some regrowth, mostly at the crown, after 6 to 12 months.

What happens if I stop?

DHT returns to its old level and the hair gained or kept is gradually lost over about a year.

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Sources and further reading (3)
  1. Propecia (finasteride) 1 mg tablets, FDA prescribing information.
  2. Kaufman KD, et al. Finasteride in the treatment of men with androgenetic alopecia. J Am Acad Dermatol, 1998.
  3. Finasteride Male Pattern Hair Loss Study Group. Long-term (5-year) multinational experience with finasteride 1 mg. Eur J Dermatol, 2002.
Educational information only. This content summarizes published research for general education. It is not medical advice, not a recommendation to use any substance, and not an instruction for human or animal use. It does not describe any Research Product sold on this site.