Meth might be on TRT, but I don't think anything serious. Past few years he's been talking about how he cleaned up his life style and eating, etc....
Busta, I think, has been on. He's like Melle Mel, he enjoys the bodybuilding stuff. He's friends with Victor Martinez's old coach and some NYC bodybuilders, plus over the past decade or so he's had noticeable swings in weight, leanness, and overall muscularity.
50 - Yes, I remember he even came up in those anti-aging clinic stings that happened years ago.