Side Effects Related to 5 α-Reductase Inhibitor Treatment of Hair Loss in Women: A Review

April 2016 | Volume 15 | Issue 4 | Original Article | 414 | Copyright © April 2016

Lauren R. Seale BS,a Ariana N. Eglini BA,b and Amy J. McMichael MDc

aUniversity of Michigan Medical School, Ann Arbor, MI
bWake Forest University School of Medicine, Winston-Salem, NC
cDepartment of Dermatology, Wake Forest University School of Medicine, Winston Salem, NC

5 α-reductase inhibitors such as finasteride and dutasteride have been studied for the treatment of hair loss in men, with finasteride being the only Food and Drug Administration-approved treatment. Increasingly, in recent years, off-label use of these drugs has been employed in the treatment of female pattern hair loss (FPHL) and frontal fibrosing alopecia (FFA) in women. Side effects with 5 α-reductase inhibitors can include changes in sexual function, and recent publications have characterized an increasing prevalence of these in men. A review of 20 peer-reviewed articles found that very few side effects, or adverse events, related to sexual function have been reported in studies in which dutasteride or finasteride has been used to treat hair loss in women. Future publications should investigate not only the efficacy of these drugs in treating FPHL and FFA, but the side effect profile in patients as well.

J Drugs Dermatol. 2016;15(4):414-419.


Finasteride and dutasteride are 5 α-reductase inhibitors approved for use in treatment of benign prostatic hyperplasia (BPH0.1,2 Finasteride is the only Food and Drug Administration (FDA)-approved treatment of male pattern hair loss (MPHL), and dutasteride is often used as an off-label treatment for MPHL.1,2,13-16 Although both drugs are teratogenic to male fetuses, additional off-label use of finasteride and dutasteride has been employed in several treatment regimens for hair loss in women.3,17-19
Two of the most common forms of hair loss where finasteride and dutasteride are used include female pattern hair loss (FPHL) and frontal fibrosing alopecia (FFA). FPHL is a form of non-scarring hair loss that causes thinning of the hair behind the hairline on the frontal and vertex scalp. Up to 42 % of Caucasian women aged 70 and older are affected by FPHL,4 with clinical signs manifesting as early as 20 to 29 years of age.6 FPHL differs from MPHL because it usually does not transition from decreased hair density to complete baldness;7 and the role of androgens in the pathogenesis of FPHL is not as well understood as in MPHL.8 A variant of lichen planopilaris,9 FFA is a form of scarring hair loss that frequently affects postmenopausal women and is marked by frontotemporal hairline recession.10
Treatment options for women suffering from FPHL and FFA include off-label use of 5 α-reductase inhibitors such as finasteride and dutasteride, among other treatments. The side effects, or adverse events (AEs), of these drugs have been established in men, and include sexual dysfunction, decreased libido, breast tenderness and enlargement, dizziness, allergic reactions, and depression;11,12 but it is unclear if these AEs occur for women. The side effects related to men’s sexual function have been published increasingly in recent years. A 2011 review by Traish et al reported that in randomized, placebo-controlled trials including only men taking 5 α-reductase inhibitors for BPH, alopecia, and prostate cancer, dutasteride and finasteride users consistently experienced drug-related reductions in or loss of libido, erectile dysfunction, depression, and gynecomastia.5 Belknap et al also recently suggested that several studies may be underreporting or underdetecting sexual dysfunction in clinical trials of finasteride for the treatment for androgenetic alopecia in men.23
In contrast, many of the studies evaluating the efficacy or effectiveness of finasteride or dutasteride for FPHL or FFA do not report the existence of AEs related to sexual libido. Changes in sexual function are a major concern for many women, especially as they approach middle age. A 2008 study of 31,581 US adult women reported that 45% of women aged 45 to 64 and 80% of women aged 65 or older reported low desire, low orgasm, or low arousal.24 With such a high prevalence in the same population that uses 5 α-reductase inhibitors for hair loss treatment, it is important to consider how side effects may impact existing sexual function problems. Since it is not clear which sexual side effects, if any, women may experience due to these drugs, as they become more widely used we aim to clarify what is known in this area. In this paper, we have reviewed 20 articles that report on the efficacy of finasteride and/or dutasteride in the treatment of FPHL or FFA, and the extent to which AEs, specifically those related to changes in libido or sexual function, were mentioned.