its not a health issue or how safe you take it thro dosage its a cheating issue pure and simple its banned in sport taking it creates an unfair advantage. True some supplements are created in the body but not in the amounts that supplements give you. As for them been harmful the bent chemists who peddle this are going to tell you its harmless ive never seen a drug dealer tell you not to buy his smack cos it could damage your health lol. The best sportsman or women should be the one who has self discipline and gets off there arse over xmas and other hard times to train and evolves thro training techniques not supplements and true a pro will push the rules fully to his advantage but taking performance enhancing drugs is breaking them rules simple as.