D-Aspartic Acid (a.k.a. DAA) is a natural test booster which has been shown in double-blind, placebo-controlled scientific studies to boost testosterone levels by 42% in humans. So finally, athletes & bodybuilders have a natural alternative to steroids & untested prohormones to boost their testosterone levels, which of course would be expected to enhance muscular recovery from exercise, increase strength & accelerate the muscle-building process. As with all PVL Essentials products, their D-Aspartic Acid is certified, researched, tested & athlete-approved.