they all do in every sport. even boxing and even ufc. most like the hgh it works wonders. the prob is over doing it. if u take roids like ur supposed to most of the side effects will not be there. like roid rage and small testies and such but these guys are taking 5 to 10 times the amount ur supposed to. when the dose calls for 100mgs a week and there doing 900 to 1500 mgs a week i think that'll do something to ya.