Low-Dose Cyproterone Acetate Treatment for Transgender Women

Background: Transgender women with intact gonads receive lifelong hormonal treatment to suppress physiologic androgen production, the optimal efficacious and safe cyproterone acetate (CPA) dose has not been established. Aim: To assess the effectiveness and safety of low-dose (10–20 mg/day) compared with high-dose (50–100 mg/day) CPA treatment. Methods: We conducted a historical cohort study of transgender women treated at a tertiary center for transgender health. Outcome Measures: Serum levels of testosterone, estradiol, prolactin, gonadotrophins, liver enzymes, and lipids. Results: There were 38 transgender women in the low-dose group and 26 in the high-dose group. Age (median 24.9 years, interquartile range [IQR] 21–30 vs 25 years, IQR 19–35) and follow-up time (median 12 months, IQR 6–23 vs 15 months, IQR 12–36) were similar in the low- and high-dose groups, respectively. Serum gonadotropins and testosterone were suppressed to a similar level at all time points in both groups. Prolactin levels increased significantly in both groups, however, with a more substantial increase in the high- vs the low-dose group (804 ± 121 vs 398 ± 69 mIU/ml at 12 months, respectively, P = .004). Total cholesterol, high-density lipoprotein, low-density lipoprotein, and triglyceride levels were not significantly affected by the dose. Clinical Implications: We suggest an adjustment of current clinical practice guidelines to recommend lower doses of CPA for the treatment of transgender women. Strengths & Limitations: This is the first demonstration that low-dose CPA treatment of transgender women is effective. Limitations include a relatively small sample and retrospective study design. Conclusion: Low-dose CPA treatment of transgender women is as effective as high-dose treatment and possibly safer. Zohar NE, Sofer Y, Yaish I, et al. Low-Dose Cyproterone Acetate Treatment for Transgender Women. J Sex Med 2021;18:1292–1298.