Testosterone and sexual risk among transmen: a mixed methods exploratory study.

Little research has explored the link between the behavioural effects of testosterone use among transmen and HIV risk. We conducted a mixed methods study to explore testosterone use among transmen and the behavioural effects on HIV risk. A sample of 122 transmen from San Francisco participated in a cross-sectional quantitative survey and 14 transmen participated in 2 focus group discussions. Most participants (81.9%) were currently taking hormones. Participants attributed testosterone use to new sexual behaviours among 69% of transmen, changes in sexual attraction (49%), and increased frequency of sexual activity (72%). Among current testosterone users, 3.3% had cisgender men as partners before starting testosterone, whereas after starting testosterone, 25.4% did. Similarly, 4.1% had a transgender woman as a sexual partner before starting testosterone and 13.9% after starting testosterone. Findings suggest that testosterone's side effects were associated with transmen's desires for sex with cisgender men who have sex with men. The reported increase in attraction to and sex with partners from populations with a high HIV prevalence may have important implications for HIV risk among transmen, especially as the availability of transgender health services may draw transmen to a context in which HIV prevalence is high.