Use of 5-Alpha Reductase Inhibitors in Dermatology: A Narrative Review

Finasteride and dutasteride are 5-alpha reductase selective inhibitors (5ARIs). They were introduced as therapeutic agents for the treatment of benign prostatic hyperplasia in 1992 and 2002, respectively; finasteride has also been approved for the treatment of androgenetic alopecia since early 2000. These agents inhibit the conversion of testosterone (T) to 5α-dihydrotestosterone (5α-DHT), limiting steroidogenesis and playing a crucial role in the physiological function of the neuroendocrine system. Therefore, it has been proposed that blocking androgen synthesis with the use of 5ARIs would be beneficial in the treatment of various diseases related to states of hyperandrogenism. This review describes the dermatological pathologies in which 5ARIs have been used as part of the treatment, evaluation of the efficacy, and knowledge of the safety profile. Specifically, we discuss the application of 5ARIs in androgenetic alopecia, acne, frontal fibrosing alopecia, hirsutism, and the implications of adverse events associated with its use to inform about the applications of 5ARIs in general dermatology practice.