It depends... SOME Pro hormones are no bullshit at all concerning muscle gains...
Take Superdrol (or a clone like mdrol) and you will see a lot of gains if you eat and train right
Pro hormone will KILL you, they will kill your liver and your health... there's no doubt about it... there are death pills
But you can definitly take 15 pounds in 8 weeks, like with Beastdrol (watch Dylan's video about it) there are no jokes concerning gains
As regards Yk-11 of course it is a marketing hype