A really good question was asked on Tumblr today:
for the non transitioning m2f who gets great relief from estogen is there a low dose and or sporadic dose which would not grow breasts much? Also, does estrogen work cumulatively, or would i.e. a one milligram a week dose accumulate?
To answer the second question first: no, estrogen does not build up in a healthy adult body. It does stay in the body longer than testosterone (about a day) but regular estrogen supplementation is necessary to keep estrogen levels up. Further, only a certain amount of estrogen in the body is “free” at any given time, i.e. available for metabolizing. Most of it is bound up with other body chemicals.
Everyone, even biological males, have naturally occurring estrogen in their system, as it is vital to some body functions. Biological males have a lot less estrogen at any given time, and so they also have a lot less free estrogen at any given time, but it’s there. The point of HRT is, in part, to bring free estrogen to biological female levels, at which point the estrogen can begin affecting the body as they would a natal female [provided one is also taking an anti-androgen, as testosterone inhibits estrogen — this is why transmen do not need to take an anti-estrogen].
Conceivably, a subtherapeutic dose is elevating the amount of free estrogen in the system above male body averages, but below female norms. I have heard of this before, though I’ve never personally known a woman on such a dose.
My question is: if such a dose is only slightly elevating estrogen over the natural body levels, is it really having any impact? There’s no clear science on that. I suspect that a dose low enough to not have any physical impact would also have little to no mental impact, and any “relief” would be a placebo effect.
I am not a doctor and I don’t recommend dosages (and DEFINITELY not self-dosing). An endocrinologist can probably answer this question better than I, and may be able to recommend a dose that elevates free estrogen without creating major biological impact.
There is another possibility for metal relief without huge physical impact: taking an anti-androgen like spironolactone without estrogen. I have known women on this regimen, and they have reported noticeable mental relief with the suppression of T. Testosterone affects behavior, and it’s possible that lowering it may do more for you mentally than a tiny boost of estrogen would. Again, a doctor or endocrinologist could discuss such an option with you more thoroughly.