ORIGINAL RESEARCH—ENDOCRINOLOGY: Long-Acting Intramuscular Testosterone Undecanoate for Treatment of Female-to-Male Transgender Individuals

Abstract

ABSTRACT Aim Testosterone treatment is essential for the induction and maintenance of virilization of female-to-male transsexuals. This study tested the suitability of a novel testosterone preparation for this purpose. Methods Parenteral long-acting testosterone undecanoate (TU) was administered to 12 female-to-male transsexuals. Observations were made while subjects received treatment. Main Outcome Measures Virilization of female-to-male transsexuals and side effects of testosterone administration. Results The testosterone levels were largely identical to those in hypogonadal men receiving testosterone treatment with TU. There were no side effects. There was a small but significant decrease in plasma cholesterol and low-density lipoprotein, but plasma high-density lipoprotein did not change significantly. Both levels of hemoglobin and hematocrit rose upon administration but remained within the physiological range. Conclusions TU is suited for induction of virilization in female-to-male transsexuals without significant side effects.