Matt C is right, there's been recent research (trying to locate the study now) that showed using a very moderate amount of anabolics, with proper diet, led to an average increase in fat free muscle mass of 6kg. Why doesn't it work for a lot of gym go-ers though? Because they don't eat right, drink too much or do recreational drugs, have an irregular sleeppattern, or a combination of the above.
then there's the case of genetics, all our possibilities are inherently genetic, how fast we learn, our degree of perseverance, how we respond to gear, muscle shape, metabolism, protein synthesis baserate, etc etc. Don't be fooled, everything we achieve in life is because our genes, not despite them.
What does this mean for BB? Some people get big natural but don't get much bigger with gear, others will get big but look like shit, others will stay pretty small but look good. Put 2 people on the same BB regime and they will end up looking different, a concept known as multifinality, whilst 2 persons doing completely different thing can end up with the same result, equifinality.
