There probable isn't a supplement that is and was studied more the creatine monohydrate which is the type of creatine creapure is. CM will not be damaging to the kidneys or cause cramping. Although you should increase your water intake if taking creatine. If your getting such great results like that I would stay on it almost year around. Research it and you will see how safe it is. I just read today that most of the kidney problem studies were poorly done.