I’ve always heard on the boards it would be possible to ruin your sensitivity with too much HCG but I have NEVER once seen it. I’ve know guys who have used it off and on for years. I know guys that have needed a little more after using it for years straight, in order to get the same effect but I’ve never seen it stop working for someone. Remember that HCG is a medical drug used to help with male reproduction around the world. Its a fairly safe compound compared to a lot of stuff we are using. As for estrogen control, smart question. Yes, estrogen can become an issue with HCG for some. Of course, dose plays a role. Arimidex would be an easy option. It’s hard to say exactly how much. If you are using 250iu to 500iu HCG, 2x wk, I would consider about .5mg Arimidex 2x wk, taken either on the days of the shots or taken the days after.