PQQ is a small quinone molecule that may help support cellular energy production as well as the body’s defenses against oxidative damage. PQQ can be used over and over again in redox reactions by conversion back into its active form. Because of its impressive potential for recycling, it is considered quite stable in comparison to CoQ10 and other antioxidants. PQQ is present in many forms around us. It is thought to be a component in interstellar dust. It has also been identified as an enzyme cofactor in certain bacteria, and as an important constituent in most plants.