Generally speaking, the younger you are, the more useless HGH will be. Most 'anti-aging' clinics won't even be willing to talk to you about it until you're 30, some say 35. At that point you'll be lucky to get 2iu per day, which is fine for feeling young and helping to stay a little leaner. Sure there are plenty of bodybuilders in their 20's using the stuff, but you've gotta understand they're running at least 4iu a day to see real results, and of course the IFBB pros use god knows how much. People speculate anywhere from 8-12 iu's or more, but when it comes to the pros, most people really have no clue, and if they do, they don't talk about it. Plus given the cost of kits and number of total scammers out there, if you're in your early or mid 20's, you're better off saving that money to build some financial stability towards being able to afford things like this when you're older.