Muscle Builder PM contains a new, botanically derived musclebuilder called CinDura®. It works by facilitating muscle energy production and promoting muscle growth while preventing muscle breakdown. In fact, in a 6-week, randomized, double-blind, placebo-controlled study, subjects taking CinDura® while following a weight training program built significantly more lean muscle (average of 5 lbs. vs. just 1.1 lbs. with the placebo group).