Then you are talking about Anti Estrogen, AntiEs, or AEs as I have never heard of it called AI. Anyway, taking them all depends on your point of view on the subject. You will get mixed feelings from this forum as to whether you should take them or not. What you might want to think about is "what are you taking them for or what are you trying to accomplish by taking them?" Do you get gyno? Do you hold excess water? These are a few of the reasons some would take them. Estrogen is needed for growth and strength and to keep a balance. Arimidex along with most of the others are known to cause problems in males. I however, take them some of the time to fight gyno, but I wouldn't take any at all if it weren't for that reason.