What is the role of finasteride in the treatment of androgenetic alopecia?

Updated: Mar 05, 2020
  • Author: Robert P Feinstein, MD; Chief Editor: Romesh Khardori, MD, PhD, FACP  more...
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Finasteride is given orally and is a 5-alpha reductase type 2 inhibitor. [31] It is not an antiandrogen. The drug can be used only in men because it can produce ambiguous genitalia in a developing male fetus. Finasteride has been shown to diminish the progression of androgenetic alopecia in males who are treated, and, in many patients, it has stimulated new regrowth.

Although it affects vertex balding more than frontal hair loss, the medication has been shown to increase regrowth in the frontal area as well. Finasteride must be continued indefinitely because discontinuation results in gradual progression of the disorder. A study in postmenopausal women indicated no beneficial effect of the medication in treating female androgenetic alopecia.

A 10-year follow-up study of men using finasteride 1 mg daily for androgenetic alopecia reported that better improvements were noted in patients older than 30 years or men who had higher androgenetic alopecia grades. Interestingly, the efficacy of the medication was not reduced with time, and in some cases improved later on. [32]

A Japanese study of 3177 men noted the efficacy and safety of finasteride in the treatment of androgenetic alopecia. Photographs were assessed in 2561 men who completed the 42-month study. Of these men, 11.1% showed great regrowth, 36.5% moderate growth, and 39.5% had a slight increase in hair growth. Adverse effects occurred in 0.7% of the men, and there were no safety problems observed with long-term use. The authors concluded that in Japanese men with androgenetic alopecia, long-term use of oral finasteride maintained progressive hair regrowth without recognized adverse effects. [33]

A retrospective study by Palloti et al indicated that in males with androgenetic alopecia, finasteride treatment can affect sperm and testosterone but is not associated with sexual dysfunction. The investigators found that 6 months after the start of treatment (1 mg finasteride once per day), the total sperm number and percentage of abnormal sperm forms had worsened, while at 12 and 24 months, aside from the percentage of abnormal forms, sperm parameters did not differ. Moreover, results from the International Index of Erectile Function–15 (IIEF-15) did not significantly vary over the course of the study. [34]

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