nobody knows exactly what these guys use. everyone has their own protocol, they are no different than all of us here. my guess is they really don't use as much gear as you think they do, only maybe when they're getting ready for a show.
you also gotta remember that all these guys have insane genetics. one of my buddies is completely natty and is a shredded 220lbs @ 6'2, stays under 10% all year round with absolutely 0 effort he eats whatever he wants and trains 2-3 times a week. he's a genetic freak its unreal. i cant imagine what he'd look like on just 500mg of test a week, but he really has no need to. shit, even if he just put full effort into dieting and training he would look nuts.
most, if not all, of the top pros have those kinds of genetics. add in 100% dedication to the sport, some anabolics, and 3 years of solid training and you get a beast.