Finasteride, sold under the brand names Proscar and Propecia among others, is a medication used to treat hair loss and benign prostatic hyperplasia in men. It can also be used to treat excessive hair growth in women and as a part of hormone therapy for transgender women. It is taken by mouth.Finasteride is a 5α-reductase inhibitor and therefore an antiandrogen. It works by decreasing the production of dihydrotestosterone (DHT) by about 70%, including in the prostate gland and the scalp.In addition to DHT, finasteride also inhibits the production of several anticonvulsant neurosteroids including allopregnanolone, androstanediol and THDOC.Adverse effects from finasteride are rare, however some men experience sexual dysfunction, depression, and breast enlargement. In some men, sexual dysfunction may persist after stopping the medication. It may also hide the early symptoms of certain forms of prostate cancer.Finasteride was patented in 1984 and approved for medical use in 1992. It is available as a generic medication. In 2019, it was the 86th most commonly prescribed medication in the United States, with more than 8 million prescriptions. Medical uses
Finasteride is indicated for the treatment of symptomatic benign prostatic hyperplasia (BPH) in men with an enlarged prostate and for the treatment of male pattern hair loss (androgenetic alopecia) in men. Enlarged prostate
Physicians sometimes prescribe finasteride for the treatment of benign prostatic hyperplasia (BPH), informally known as an enlarged prostate.
Finasteride is most effective on the crown but can reduce hair loss in all areas of the scalp. Finasteride has also been tested for pattern hair loss in women; however, the results were no better than placebo. Finasteride is less effective in the treatment of scalp hair loss than dutasteride. Prostate cancer
In males over 55 years old finasteride decreases the risk of low-grade prostate cancer but may increase the risk of high-grade prostate cancer and has no effect on overall survival.A 2010 review found a 25% reduction in the risk of prostate cancer with 5α-reductase inhibitor. A follow-up study of the Medicare claims of participants in a 10-year Prostate Cancer Prevention Trial suggests the reduction in prostate cancer is maintained even after discontinuation of treatment. However, 5α-reductase inhibitors have been found to increase the risk of developing certain rare but aggressive forms of prostate cancer (27% risk increase), although not all studies have observed this. No impact of 5-α-reductase inhibitor on survival has been found in people with prostate cancer. Excessive hair growth
Finasteride has been found to be effective in the treatment of hirsutism (excessive facial and/or body hair growth) in women. In a study of 89 women with hyperandrogenism due to persistent adrenarche syndrome, finasteride produced a 93% reduction in facial hirsutism and a 73% reduction bodily hirsutism after 2 years of treatment. Other studies using finasteride for hirsutism have also found it to be clearly effective.