This clinically-backed muscle building formula delivers powerful results when they matter most. Muscle Builder features a scientifically-dosed key ingredient that will boost strength and performance.­ Hard-training subjects, in a 12-week human scientific study, gained 8.8 lbs. of lean muscle versus the placebo group, which only gained 4.6 lbs. – that's 90% more lean muscle! The same subjects experienced an increase in strength that was 147% more than the strength increase achieved by the placebo group.