cenegenics but is a vocal critic of the anti-aging provement. >> i believe it's quackery. >> reporter: he says there's no rhettable studies. and warns it can enlarge organs, even trigger cancer. >> what do you say to the medical community who says you're selling a bunch of voodoo and this is potentially dangerous because it's so untested. >> we don't know what the long-term consequences are going to be of testosterone replacement therapy and growth hormone replacement therapy. >> what's wrong with getting old? >> that's an argument a lot of doctors use. who wants to get old if you don't have to. >> if next year for some reason you get cancer, will you blame these supplements? >> no, i will not. >> reporter: what he will do is continue to be the post ever grandpa of a company and a movement that believes the riskier move is to turn away from this fountain of youth they found in diet, dumb bells and drugs. kyung lah, cnn, las vegas.