When you drop the gh and insulin you deflate rapidly, gh/insulin combo gives you a volumized look, but it's just water it's not dense muscle, so when you pull these compounds the weight flies off.
I agree, although its not "just water". The muscle cells are actually larger, volumized, filled with glycogen etc, increased bloodflow and so are actually bigger. But yes, these guys do deflate fast when off...
Even just guys off the tren, they loose the edge, both physically and mentally they get deflated. Look at Von Moger as a classic example.