i am one of those people i guess you would call "lucky"....i never used them, when i did they destroyed my sex drive. Now that i am monitored frequently via blood work i realized why. While on 500mg of test enanthate per week my e2 rose to only 42...now that is still a little higher than what i would call optimal. so i added .25mg arimidex EOD...pretty paltry amount by most standards. It drove my e2 down to 9...way too low. So for whatever reason my e2 just does not elevate that much in comparison to most and i also over respond DRAMATICALLY to AI's. I literally never once had any gyno issues or related estrogen side effects (except some water retention) even while on 1.5-2 grams of test per week. Now i take only 200mg per week by script and my e2 hovers right around 25 with no AI , according to common "bro knowledge" this is impossible but my blood work is done every 12 weeks. It kills me to read some of AI recommendations, guys act like if they are on 500mg of test they need to be taking .5 to 1mg of arimidex per day...of course none of them have any blood data to back up these beliefs other than internet board knowledge. There is really only one way to know...get your blood work...go by THE FACTS not what some internet guru tells everyone.