Molecular Hydrogen (two atoms of hydrogen combined into one molecule) is a powerful antioxidant that selectively targets the most toxic of free radicals, the hydroxyl group. The ability to selectively target free radicals is important as it means that it will not interfere with adjunctive therapies doctors may be pursuing. The healthy body creates free radicals as a result of normal activity & metabolism. These free radicals, known as ROS (reactive oxygen species) or RNS (reactive nitrogen species) are kept in check by the healthy body, maintaining normal mitochondrial function and minimising oxidative stress. Healthy and unhealthy individuals create oxidative stress. Exercise increases a person’s use of oxygen, and increases the work load on the mitochondria. As a result, professional athletes create higher oxidative stress (free radical activity) levels than those who do not exercise to the same extreme. Those facing health challenges may promote a less than optimal level of oxidative stress. The point is that oxidative stress occurs on an ongoing basis and for a variety of reasons. Due to its low atomic mass, hydrogen gas has the unique ability to penetrate the blood brain barrier and every compartment of the cell, including the mitochondria.