Look at the range of those publication dates. Some are as old as I am, and only five of them were performed in the last decade. These aren’t lazy providers, for clarity! They’re doing their best! The focus on our health is just that bad. Take this study on progesterone, for example—it set out to see if progesterone affected breast growth in trans women… and ran for three months. On nineteen participants. That’s a ludicrously small sample and time period.
That, coincidentally, kind of brings us to the point: I’ve said a whole bunch that all science has a half-life, right? Well, back when most of the “recent” research was done on the effects of estrogen and testosterone on trans people, “the duration of puberty was [thought to be] 1.96 +/- 0.06 years” for cis girls, for instance, and a similar length for cis boys. In the last twenty years, however, a lot more science has been done, prying that window wider and wider, at least doubling that length, now, strong data says that puberty lasts around 10-14 years. It makes sense that doctors studied HRT the way that they did. When they did it, they thought that that was as long as puberty lasted. That part just… turned out to be wrong.
Simply put: trans folks are a marginalized, oppressed group which relies on the dominant group to research our medical needs. We, in general, don’t get a say in the research done on us, and it’s why I haven’t—and won’t—write an article about best practices on HRT that’s more specific than “stay within either male or female ranges, or work with an endocrinologist to find a nonbinary combination of estrogen and testosterone that’s right for you.”
We don’t have the research data.
And frankly? It’s not coming. I’m not aware of any meaningful, long-term research that compares different methods, doses, or approaches for HRT that’s currently in process.