Transgender women on oral HIV pre-exposure prophylaxis have significantly lower tenofovir and emtricitabine concentrations when also taking oestrogen when compared to cisgender men.

GAHT modestly reduces both TFV and FTC plasma concentrations. In TGW taking GAHT, it is unknown if this reduction will impact the HIV protective efficacy of a daily PrEP regimen. However, the combination of an on demand (2 + 1 + 1) PrEP regimen and GAHT may result in concentrations too low for reliable prevention of HIV infection.