I agree with l.o.t.i28. but if your going to use it no matter wat people or knowledgeable say pm me and ill help you. but like my above friend said you should grow to maximum before and if you need it. but the law is its legal to use and also is legal on the customs alert list. I only used for a competition to bring up lagging arm size. u don't go overboard as like greg valentine, others. yes it will put size on you but you aint going to see 3 inches in 30 days unless your over doing it. plus know where your nerves are in your lagging bodypart. so I don't want to piss no one off but ill help you if your going to u my as well do it safely. pm me and ill tell you how to use it in any lagging bodypart. I don't have info for forearms as theres just to much risk in that muscle. calfs are tricky to.