Evista is not an AI first off, it is a SERM like tamoxifen and clomid. However, it is much better than the 2 for OCT purposes, and it is also mcuh better for you. I.e. doesn't affect cholesterol and igf-1 levels in such a negative manner. It actually IMPROVES cholesterol levels by lowering total and LDL cholesterol by roughly 6-11%. My personal favorite however, is Fareston(Toremifene) for PCT purposes. I am "on" for the rest of my life, as I made that committment, so I no longer do PCT's, and this no longer applies to my personal plan. I always urge others research Fareston though, you will be glad you did.