Mostly testosterone for building the muscle base probably, then potentially something like anavar (oral oxandrolone) for a few weeks before filming the shirtless scenes, as orals make you temporarily blow up with water and glycogen. Could be some use of diuretics before filming, too - they definitely use water manipulation/restriction to get that ultra-lean look on the day. I've only included drugs you could feasibly get from the doctor, rather than anything too exotic. I do, however, guarantee they all used a significant amount of steroids in addition to the extremely strict diet and training they are very keen to talk about.