The NEXT BIG Discovery to assist our own BIOLOGY. The Science Behind Molecular Hydrogen The Free Radical Theory of Aging >> The Free Radical Theory of Aging holds that the damage free radicals do to our cells, particularly the oxidative stress that free radicals cause, is what causes our bodies to age. As we age, our internal defense system declines, allowing oxidative stress to accumulate and resulting in cell damage, disease and death. How H₂ Works Size Molecular hydrogen is the smallest