Before anyone answers the harm question, two numbers that get skipped. First, the anastrozole evidence base in men is thin and mostly borrowed. The drug was developed and trialed for postmenopausal breast cancer, where the goal is to suppress estradiol as close to the floor as the assay can read. That is the dose-response that got studied to death. The hypogonadal-man literature is smaller, often open-label, and the few RCTs I have read were not powered to tell you what a man on TRT actually wants to know, which is where the useful E2 floor sits before you start losing bone, lipids, and libido. So part of the polarization is just people arguing past a gap in the data. Second, half-life is roughly 48 hours. That is the part the forum fights miss. Anastrozole accumulates to steady state over about a week, so the dose you take Monday is still working on you Thursday. People take a tablet, feel flat two days later, read that as “E2 too high, need more,” take more, and drive themselves into a crash they then blame on the drug. The drug did exactly what it does. The dosing interval was wrong for the kinetics. The mechanism that AIs lower estradiol is demonstrated and boring. The claim that low-dose anastrozole is “safe” for chronic use in TRT men is plausible but not well demonstrated in humans at the timescales that matter. Question before anyone gives you a number: what is your actual sensitivity E2, your dose, and how often are you injecting? Aromatization tracks frequency and bf%, as you said, and that usually moves the needle more than a tablet does. Short version: it is not harmful per se, it is a long-half-life drug that punishes impatient dosing, on a thin evidence base. Fix frequency first.