arimidex is what my doc prescribed me, I take .5mg the day of injection, remember I inject every 3.5 days. I am a big man (fat) which means I convert more testosterone to estrogen than someone a lot leaner and I also am on 200mg's of test a week. It is not for me to tell you how much to take but I would guess .5mg at the time of injection would do you fine. If you are self injection you should really consider splitting up your injections to every 3.5 days instead of once every 14 days. You may not even need a AI if you do that plus you will have steady levels instead of a high peak and then crash after 6-7 days.