So you believe he's on hrt??? And just hrt???
By his own words, he uses one Nebido every six weeks. His weight in the picture is 98 kg/216 lb, he's dieting for the Nordic Fitness Expo 10-11 October 2015 in Lahti Finland. He has still couple of kilos to loose from that condition, he want to be 96 kg at the show. He has quite slow diet because he doesn't want any complications with the donated kidney, like he has year before.
When he was making his comeback before the kidney failure, he was making 50 kilos of muscle in six month with the gear. Now he has gain 20 kilos in few years, and it's not any kind of miracle for the guy who has weight 110kg on stage. Those muscle fibers doesn't go anywhere, you just need to stimulate them again and get them filled. With gear you can do it faster, but if you can't use gear, all you have to do is do it slower. Marko has his own supplement series done with the A.Manninen Nutraceuticals, so these guys has cooked up things which works for him. For example, he doesn't take protein as supplement, he uses plain amino acids instead. His way of training (ultra heavy duty) gives best gains for natural bodybuilder, he has years of experience and those frequently mentioned genes for the sport, so let see how it goes?