Can a person develop a tolerance to Arimidex?..where Arimidex stops working to block E2?
No but you can take to much HCG and make E2 unmanageable.
To clarify Brent’s comment: Too much hCG or a SERM can increase LH to the point that T–>E2 goes wild inside the testes. T levels there can be 80-100 times higher than serum levels, so a competitive AI cannot do anything about that source of E2. A rare few are overly sensitive to hCG, there testes simply do not work the same as most others. I also suggest that one avoid large amounts of hCG or a SERM and to not stack both.
We had one thread where a doc had a guy in this situation. The doc did not understand and kept increasing the dose of anastrozole. I then realized why the anastrozole was not able to bring down serum E2 levels.
I’ve never heard of a case where Adex quits working… Besides what KSMan is saying above, of course…
Most guys find that Adex lowers their E2 too much, and they find themselves cutting the dose once they slide through the sweet spot on the way down. You don’t want to run your E2 into the ground, because men need estrogen for many reasons. As my doc says, “I believe in evolution, and there is a reason men have a naturally occurring E2 level around 20, even if we don’t fully understand what that is…”