Serum levels at 20-45nl/mg of estradiol are normal and provide all the anabolic effect estrogen can provide. The problem is knowing your estradiol level, which can only be measured through a blood test. Experimenting with AI's and SERM's are all we have unless you can afford a blood test every 2 weeks.

We know through scientific research that anastrozol (arimidex) at 1mg/day will reduce free estrogen by 50% in AAS-using males, averaging 600mg/wk of test. But 50% of what value? For gyno mitigation or protection, tamoxifen (Nolvadex) is the staple. And it helps normalize the HPTA. But it won't prevent other estrogen sides like bloat and SHBG suppression. Aromasin (Exemestane) at 15-25mg/day will suppress aromatization by 97% in AAS-using males averaging 600-1,000mg/wk of testosterone. But 97% of what amount? If we reduce estradiol to below 20nl/mg, we begin to reduce a percentage of muscular hypertrophy.

Longterm experimentation by each user is crucial in finding the proper dosing protocol. Vets in the game have some knowledge of what works for them and can be used as a starting point on similar cycles.

As far as prolactin induced through nandrolone-based steroids, there is plenty of anecdotal evidence that it rises to levels producing gyno. I've experienced it and have mitigated it with cabergoline at 1mg/e3days.