Much of these reported changes are anecdotal, shared within the trans community as we compare notes on our experiences in an attempt to learn the specifics of what HRT might do for us and what we might expect as we continue transitioning. These qualitative reports are significant and useful, providing detailed information beyond the more general lists of changes we’re typically given by medical providers when starting HRT. And the sexuality-related experiences of trans people, running certain sex hormone levels on “nonstandard hardware” and complicated by the presence of dysphoria with one’s body and assigned gender, can be distinct in various ways from those of cis people, calling into question the conventional assumption that more testosterone means more libido and less testosterone means less libido. And a recent study, while necessarily more coarse-grained than descriptions of personal experiences, helps to clarify just how much sexual desire tends to fluctuate in trans women and trans men while undergoing HRT.
Defreyne et al. (2020) examined levels of sexual desire in 401 trans women and 364 transgender men before starting HRT and at 3, 6, 9, 12, 18, 24, and 36 months after starting HRT. Sexual desire, defined as “interest in sexual activity, which can be measured by amount and strength of the thought directed towards sexual stimuli”, was measured by the Sexual Desire Inventory (SDI). The SDI measures dyadic sexual desire, the desire for sexual activity or intimacy with another person, as well as solitary sexual desire, referring to interest in self-directed sexual behavior.
The authors reported that at baseline before initiating HRT, trans women had a greater solitary SDI score than trans men. Trans men, after 3 months of HRT, showed in increase in solitary, dyadic, and overall (combined) SDI scores. By 36 months, their total and dyadic SDI scores had shifted back to the pre-HRT baseline, but solitary SDI remained higher than the baseline. Conversely, trans women experienced a significant drop in dyadic, solitary, and total SDI scores after 3 months of HRT, but by 36 months their total and dyadic sexual desire was increased compared to the baseline and their solitary sexual desire was similar to the baseline. Notably, during the first year of HRT, trans women reported being comfortable with a greater length of time without sexual activity, while trans men experienced a decrease in the length of time they were comfortable without sexual activity.
Other factors were also found to be associated with changes in sexual desire: trans women who had undergone orchiectomy showed a greater increase in their total and dyadic sexual desire at 24 months than trans women who had not undergone orchiectomy, and total and dyadic sexual desire did not appear to be influenced by breast augmentation or vaginoplasty. Additionally, trans men who had hystero-oophorectomy showed a greater increase in total and solitary SDI scores at 12 months; chest reconstruction surgery or phalloplasty did not appear to have an effect. Trans women with lower intensity of gender dysphoria as measured by the Utrecht Gender Dysphoria Scale had higher total and dyadic SDI scores at baseline, and higher solitary SDI scores after one year of HRT, and those with less body dysphoria as measured by body image at baseline had higher dyadic SDI scores after one year.
The findings of this study are quite contrary to what might be expected from the usual effects of testosterone or the lack thereof: not only are estrogen-driven decreases and testosterone-driven increases in sexual desire apparently temporary, but in the long term HRT appears to increase sexual desire above pre-treatment baseline in trans women, and trans men’s sexual desire returns to baseline. These results underscore the fact that trans people are a distinct population from cis people of the same assigned sex, and can experience distinct and unique effects from hormone treatment – effects that trans people have anecdotally reported among themselves for quite some time. ■