I was doing a PubMed dive today and I came across this study from last December that explores the question: do different hormone regimens cause better or worse breast development in transwomen?
It’s a fair question. Just like two types of pain reliever don’t treat a headache the same way, different HRT regimens may have different biochemical mechanisms that could impact breast development. But breast size is subjective, of course, and body type can also impact whether or not breasts are “big enough.” So rather than do some objective measure of cup size, circumference, or whatever, the study chose instead to measure how many transwomen sought mammoplasty (i.e. breast implants) after two years of HRT.
The study specifically tracked use of either estrogen valerate, ethinylestradiol, or conjugated equine estrogen (CEE), and also tracked the variety of anti-androgen used. The results are interesting:
There were significantly more self-medicating individuals than controls in the mammoplasty group (11.5 vs. 6%, P < 0.05). The type of estrogen use did not affect the outcome. Compared with other antiandrogens, spironolactone use was significantly higher in those requesting mammoplasty (4.8 vs. 1.8%, P = 0.002).
In short: women who self-medicated had less satisfactory breast development than those who were under a doctor’s care regardless of the estrogen they used. This is far from surprising. Women under professional care are routinely having their hormone levels tested and their HRT adjusted, while self-medicating women usually are not. Thus, self-medicating women aren’t getting the kind of consistent development that adjusted estrogen levels confer.
Also interesting is that bit about spironolactone. Here in the United States, spiro is one of the most common anti-androgens prescribed (especially since cyproterone acetate, the other common antiandrogen used in HRT, lacks FDA approval). I guess we American transwomen are going to have to settle for being a little less well-endowed up top.
Self-medicating women using spiro would appear to be a double-whammy of lesser breast development. There’s a whole host of reasons why transwomen should not self-medicate, as it can lead to serious problems including death, Smaller breasts would seem to be a minor issue in comparison, but it’s another one to add to the list. Especially since, as the authors note, “Breast development in transwomen is an important issue, affecting general psychological functioning.”