i wont talk down to or tell someone what to do or not to do. with that said at 21 i say you should hammer the hell out of yourself and reach as far into your max potential before taking the plunge. if you are healthy you natural levels dont even start to decline in most men until 25. so why rush the process? these ignorant ass holes think that they can build a champion physique by what and how much they take. you cant cut corners and it is only a small factor of the equation in our game