Since Tamoxifen is an agonist antagonist medication, how do you know if your Estradiol values are in the range you would like?
There is an estradiol sticky. Read that and other stickies.
Your question is double talk.
SERM’s never reduce E2 levels, typically increasing E2 levels. To reduce E2 levels, you need to use an aromatase inhibitor [AI]. Lab work for estradiol is part of the routing labs that are needed.