When not on TRT, your LH/FSH levels depend on negative feedback effects of T and E2, E2 the dominant player. Then reducing E2 can increase LH/FSH and T levels.
When on TRT, LH/FSH–>zero and reducing E2 can not do anything as above.
In both cases more E2 increases SHBG produced by the liver which scavenges sex hormones from the blood. More SHBG means more SHBG+T which means less FT. SHBG+T is tightly bound and not bio-available. So while more SHBG+T means higher TT, the higher TT number is more SHBG+T junk and you gave less T benefits with more TT. Reducing E2 will cause SHBG to slowly drop, increasing FT which is good. E2 also interferes with T at T receptors, so there is a benefit there with less E2. E2 also drive gene expression that is opposite to what we want T to do. All of this needs to be tempered by a view point that understands that there is a optimal E2 level near 22pg/ml - 80 pmol/L that works great for almost all guys, some thrive better with more E2.
When you add AI, E2 will drop, SHBG should reduce and FT increase. TT may change a bit. All of this depends on your SHBG levels and how that responds. Some just have high SHBG and some simply low. And some have extremes driven by medical problems or starvation diets.
Post labs with ranges and more info about you.
Did you test LH/FSH or prolactin before starting TRT?
Please read the stickies found here: About the T Replacement Category - #2 by KSman
- advice for new guys
- things that damage your hormones
- protocol for injections
- finding a TRT doc
Evaluate your overall thyroid function by checking oral body temperatures as per the thyroid basics sticky. Thyroid hormone fT3 is what gets the job done and it regulates mitochondrial activity, the source of ATP which is the universal currency of cellular energy. This is part of the body’s temperature control loop. This can get messed up if you are iodine deficient. In many countries, you need to be using iodized salt. Other countries add iodine to dairy or bread.