A systematic review of anti-androgens and feminisation in transgender women.

Abstract

Anti-androgens are frequently used with estradiol in transgender women seeking feminisation. Anti-androgens act by various mechanisms to decrease the production or effects of testosterone, but it is unclear which anti-androgen is most effective at feminisation. A systematic review was performed using PRISMA guidelines. We searched online databases (Medline, Embase and PsycINFO) and references of relevant articles for studies of anti-androgens in transgender women aged 16+ years to achieve feminisation (namely changes in breast size, body composition, facial or body hair) or changes in serum total testosterone concentration when compared to placebo, estradiol alone or an alternative anti-androgen. Four studies fulfilled eligibility criteria and were included in a narrative review. The addition of cyproterone acetate, leuprolide and medroxyprogesterone acetate may be more effective than spironolactone or estradiol alone at suppressing the serum total testosterone concentration. Body composition changes appear similar in transgender women treated with estradiol and additional cyproterone acetate or leuprolide. No eligible studies adequately evaluated the effects of anti-androgens on breast development or facial and body hair reduction. It remains unclear which anti-androgen is most effective at achieving feminisation. Cyproterone acetate, medroxyprogesterone acetate and leuprolide may be more effective than spironolactone at suppressing the serum total testosterone concentration. However, due to spironolactone's antagonism of the androgen receptor, it is unclear whether this results in clinically meaningful differences in feminisation. Further research with clinically meaningful endpoints is needed to optimise the use of anti-androgens in transgender women.