The problem is more than simply the gene being turned off. Let's say that the myostain gene is also in cardiac muscle too, there would be cardiomegaly as a side. If it were in smooth muscle, all the muscular layers of intestinal lumens would gow worse than gh-gut. Even then, that's not taking into account that cartilage isn't vascular and can only grow about 5% a year so there would be increased injuries. Of course it would have to be injectable with another steroid.
Is it possible to turn on/off genes? Sure. My point is turning off a gene in a stable population wouldn't necessarily cause muscle growth. Yes, it might change (shorten) the cell cycle but my guess is that no supplent company is going to make something that a lot of people would respond to.
I'd be more inclined to believe that a company was using mRNAi to shut off myostatin production. Sort of what they're doing for macular degeneration.
If something sounds too good to be true....... it probably is.
