my personal answer is there are better and safer things to use unless your extremly gyno prone. letro can reduce estrogen levels more then you want. you want to keep your estrogen levels low but not to low or eliminated or problems can occure. in my opinion letro should only be run to eliminate gyno or before a competition when you need that extremly dry look. there are better options out there like armidex which will lower your estrogen levels but keep them high enough so you'll still gain from it