Hello!
TLDR: get yourself tested for Testosterone and Estradiol levels. It’s probably not that expensive. Breast bud development is permanent, so if this bothers you, you should probably stop.
HUGE DISCLAIMER: I am not a doctor. My speculations and my advice should not be considered actual medical advice. Take everything I say with a grain of salt.
Trans woman here from a STEM background, and I have read some literature on HRT, so I know a bit about breast growth and hormones. I’ll first talk about breast growth and hormones, then I’ll talk about what could be happening to you, and what you can do.
Breasts and Hormones
In general, breast growth can be attributed to both a lack of testosterone (I’ll call this T from now on) and the presence of estradiol (I’ll call this E from now on) beyond a certain threshold. Both factors are semi-independent.
Why independent?
You can have both too much T and too much E, too few of both, too much of one and too few of the other, etc…
Why semi independent?
Your body has some built-in control mechanisms to balance your hormones.
- It can (and probably will) convert T to E if you have too much T.
- If you have too much E, your body will produce something called SHBG, which will bind to both E and T, reducing their impact on your body.
- Probably a bunch of other checks and balances.
How do both hormones relate to breast growth?
- In very simplified terms, the default state of the human body is “female”. T suppresses breast growth, and if you have too few, you can start developing breasts. We know this happens because castrati and eunuchs of bygone eras are recorded to have experienced some breast growth after the removal of testicles, despite not taking any E.
- E encourages some breast growth (but YMMV) so an excess of E even if you have enough T, will also cause you start developing breasts. We know this happens because some steroid users develop breasts despite having an excess in T (and some of that T is converted to E)
- Again, in very simplified terms, there is a delicate balance of high-enough T, and low-enough E, where you do not develop breasts. Any other combination (Both high, both low, high E low T) will cause some breast development.
What could be happening to you
Each person’s body is different. The fact that many of us in this forum have hair follicles that are sensitive to DHT, while the rest of the population does not, is a testament to this. Likewise, there are a number of known reactions to the reduction of DHT.
Generally speaking, our body is used to a certain balance of things. Outside that balance, it will try to bring itself back into balance. For example, your body expects some concentration of blood sugar. If there’s too much, the pancreas will produce more insulin to either store or use the glucose, and consequently your blood sugar will decline. If there’s too little, there’s a different mechanism involving a molecule called glucagon.
Likewise, your body expects some amount of DHT. For many people, if your DHT drops below an expected range, your body will try to produce more T (because the 5ar enzyme converts T to DHT) Over time, your body will get used to the new level of DHT, and bring T back down, but when this happens, and to what degree, varies from person to person.
Case A
- You’re taking 5ar inhibitors, DHT goes down
- Body is like, “whoa, where did the DHT go?”, and makes more T.
- Your T levels rise, but not to the point that your body converts some to E. You have more energy, and have pretty good mood.
- Your body does not stop elevated T production, and T goes into excess, triggering the aromatase pathway. You now have too much T and E. Gynecomastia, and mood imbalance happens.
Case B
(1-3 copied from Case A)
4. Your body realizes that the decreased DHT is the new normal and your body decides to wind down T production.
5. Your body winds down too much for some reason, and now you have a lack of both T and E. Gynecomastia, and mood imbalance happens.
Case C
(1-4 copied from Case B)
5. Your body winds down T production back to normal, but it just so happens that your body has some mutation wherein the DHT in your body was doing more of the heavy lifting for both mood and the suppression of breast development. Now that you don’t have enough DHT, you’re experiencing these symptoms, despite having normal T and E.
This is all speculation. I could be right on the money, off by a bit, or completely off. But the point I’m trying to make, I guess, is that you are probably right that it’s hormonal.
What you can do about this
The ideal would have been, as would be the case for anyone taking HRT to transition, is to take baseline hormone readings before taking medication. At the very least, T and E. (DHT too, if you can afford it) But chances are you haven’t taken any hormone baseline.
It’s still useful to take hormone readings now because while we will likely never know the exact change in your hormone levels, we are aware of general normal ranges for the population in general, and can thus see if your levels are out of expected ranges.
In my country, testing T and E together costs about 50-60 USD. It’s not cheap, but it’s not terribly expensive. I don’t know how it is in your country. If you can afford it, it can help you know for sure if there’s something off about your hormones. This test can also help you identify your next steps.
For example, if you have an excess of both T and E, then it’s possible that you simply need to wait until your body gets used to your new DHT levels, and then maybe your T goes down on its own back to normal, and likewise for your E.
If it turns out your T and E are too low, then you’d have to take a different path.
As I said in the TLDR, breast bud development is permanent, so if this bothers you, you should probably stop taking fin/dut. If you’re okay with a bit of puffiness, then proceed at your own risk.