OK, let's try being honest now. Both of these are going to modulate hormones, meaning there is no 100% to not having any worries about gyno. The Erase should help prevent it and this is a good stack, but the only 100% way to combat it is not to take it. There have been others that have been prone to gyno and have been perfectly fine. It also depends on how you got the gyno initially. Was it naturally or from supplement or steroid use? Even that matters because there is a difference between reacting to supplements and reacting to steroids. Sorry to go on and on, but there is really no 100% way know.