I've recently gone through this with a teammate who is just hitting his stride at 20y/o...... another close friend and training partner was just told by a coach who is well known for his high dosages that he should stay natural for as long as possible if he's still getting good gains.
The problem is that kids go in to the gym uneducated, they make 6 month beginner gains and then hit reality, then justify everything to themselves like drugs are the only thing holding them back when in reality their training sucks, they're still babies, and their nutrition is a flash in the pan at best.
Every supplement is an ace card and you can only play it once. If you gear up to squat 500 you'll probably never squat a grand. If you go on the Dave Polumbo ( sp?) protocol and wreck yourself to get a pro card you'll never be a top contender.
I know guys who are handling 900+lb benches and 1100lb squats and are drug free. They're still making great progress so why would they go on?
The final part to consider is why. Why risk anything? Health, legal, financial, whatever..... I don't understand the gym rats who run insane cycles and never compete at anything. On our team, new lifters owe us one year of competing in tested divisions before they are even welcomed to consider the choice.