There's no secret. Sure, he's gifted structurally but when it comes to pure mass, he is on an insane, massive dose of AAS, GH and insulin. His entire body is a site inject cushion, quads especially. Doesn't take away from his physique though. Like any other pro on these doses, he won't look too sharp for long.
If I ever started balding, i'd probably blast the shit out of my body. No more hair to lose, everything else to gain. Shit yeah.