Assessment of Gender-Affirming Hormone Therapy Requirements

Purpose: There are currently no recommendations regarding the starting doses of hormone therapy for individuals with gender dysphoria. The purpose of this study was to assess the hormone dose needed to achieve target hormone levels in transgender men and transgender women, and whether body mass index (BMI) affects these doses. Methods: A retrospective chart review of subjects seeking gender-affirming hormone therapy was performed. Height, weight, hormone doses, and serum hormone levels were collected from charts. Data were analyzed for a correlation between BMI and effective hormone dosing (dose that achieved hormone levels in the target range). Results: Charts from 319 subjects were reviewed; however, only 84 transgender women and 71 transgender men had serum hormone levels available and only 40 transgender women and 54 transgender men had plasma hormone levels in the target range (normal range for affirmed gender). For transgender women, there was a significant negative correlation between BMI and effective estradiol dose (r = -0.337, p = 0.04). For transgender men, there was a positive correlation between BMI and effective testosterone dose (r = 0.409, p = 0.002). Conclusion: Increased BMI was associated with lower estrogen dose requirements in transgender women. In transgender men, an increase in BMI was associated with increased testosterone dose requirements. These results suggest that BMI may influence effective gender-affirming hormone dosing; however, further studies are needed to examine its utility in determining the initial hormone dose.