Is there a role for 5α-reductase inhibitors in transgender individuals?

This commentary will explore the important clinical question regarding whether the antiandrogen class of 5α-reductase inhibitors should be considered as an effective and safe treatment option for transfeminine and/or transmasculine individuals. The use of finasteride in transfeminine individuals is based upon the theory that the goal of medical treatment is to reduce the concentrations of androgens, including dihydrotestosterone. Nonetheless, it is unclear that finasteride will have any additive clinical benefit once testosterone levels have already been lowered with standard treatment regimens (i.e. estrogen with spironolactone or cyproterone acetate). For transmasculine individuals, 5α-reductase inhibitors may be a potential treatment option for a subset with androgenetic alopecia but may come at the expense of impairing virilization driven by dihydrotestosterone. In the absence of efficacy and safety data on 5α-reductase inhibitors in gender diverse populations, clinicians should discuss this issue with patients who request or are contemplating their use.