Michael Ristow is a Professor of Endocrinology and Diabetology, as well as Director of the Institute for Experimental Endocrinology at Charité - University Medicine Berlin. He is interested in the biochemical and molecular basis of longevity — in particular the role played by mitochondria in lifespan regulation Contrary to the widely re-iterated Free Radical Theory of Aging, Ristow was the first to show that the health-promoting effects associated with low caloric intake, physical exercise and other lifespan-extending interventions like sirtuin signaling are caused by increased formation of Reactive Oxygen Species (ROS) within the mitochondria, causing a vaccination-like adaptive response that culminates in increased stress resistance and extended longevity, a process called mitohormesis. He works with the roundworm C. elegans and mammalian model organisms, as well as humans.