When I actually started taking AIs, I got bunk arimidex. I switched back to regular RC company and ran Aromasin at 10mg ed (that is how they have it dosed per mL). I started at 10mg but the normal dose seems to be 12.5mg ED. I noticed when taking it (I run all short esters, i.e. test prop, tren ace) I would bloat up as usual and gain a good 6 pounds within 5 days, and then maybe 3 days later I would drop 3 of the 6 lbs (I assuming this is from the Aromasin, without it I just stay puffy). I think I will start running my AI a few days prior to starting my cycles.
Only reason I started running AIs is because my estradiol levels were high. At 700mg of test prop I was running CEM arimidex at .25, bumped up to .5mg ED and E2 was still 78+ pg/mL. I really don't have any issues with gyno, but my nipples start to get puffy when I run prop at around 700mg a week (100mg ED). I never had issues otherwise running prop around 500-600mg a week except bloating bad. Even though I run test prop at like 70mg ED now and Tren Ace at like 70-80mg, I still use an AI because it prevents the excessive weight gain and the puffy stomach.