Oxidative stress it is a form of "chemical stress" induced in our organism by an imbalance between the production of highly reactive chemical species (free radicals) and the level of physiological defense capabilities (antioxidants). In addition to the preliminary definition, oxidative stress has had its own evolution over the years, just think of Sies 1958 and then Jones 2006. Its pathogenetic role can be direct and corroborated or indirect and poorly corroborated. Furthermore, there are studies with its link to senescence, even ambiguous ones. And finally, complex antioxidants work better than simple ones.