I think that Nelson hit it dead on here. (How about that Nelson? GRIN) I would like to further add that once you hit your genetic potential and continue to make gains while on steroids there is also a limit to how much you can gain. That limit gain be extended by use of gh and insulin but still a limit. Further that limit is much more obvious in older users(IMO). This is, of course, my opinion rather than researched fact since it is unlikely that any studies exist exploring this.
jb
jb