Physical and Psychological Effects of Gender-Affirming Hormonal Treatment Using Intramuscular Testosterone Enanthate in Japanese Transgender Men

INTRODUCTION: The evidence on gender-affirming hormonal treatment (HT) for transgender persons is still insufficient. AIM: To characterize the physical and psychological effects of HT using testosterone enanthate in transgender men, and to validate the safety of this treatment. METHODS: A total of 85 Japanese transgender men who were followed up for at least 1 year at our gender clinic from 2004 to 2017 were included in this study. All self-reported effects that they recognized and regularly acquired laboratory data were investigated after initiation of HT. MAIN OUTCOME MEASURE: HT mainly using testosterone enanthate 250 mg every 2 weeks caused the most desired physical effects to appear promptly and effectively, whereas small but not negligible numbers of undesired physical and psychological effects were also confirmed. RESULTS: The initial dose of testosterone enanthate was 250 mg for 72 (84.7%) subjects, and the injection interval was maintained every 2 weeks for 70 (82.3%). Most physical effects appeared within 6 months. A deepened voice (87.1%), cessation of menses (78.8%), acne (69.4%), and facial (52.9%)/body (37.6%) hair growth occurred within 3 months. Although recognition of psychological effects was rare, emotional instability (9.4%) and increased libido (7.1%) appeared in the relatively early phase after beginning HT. The mean values for red blood cells, hemoglobin, uric acid, and alkaline phosphatase were significantly increased for 2 year. During the observation period, there were no life-threatening adverse effects in any subjects. CONCLUSION: The present HT strategy is effective and safe for Japanese transgender men. The information from self-reported effects and objective data from blood tests can help both physicians and transgender men to understand testosterone HT. Kirisawa T, Ichihara K, Sakai Y, et al. Physical and Psychological Effects of Gender-Affirming Hormonal Treatment Using Intramuscular Testosterone Enanthate in Japanese Transgender Men. Sex Med 2021;9:100306.