There is growing evidence that early, intensive treatment of new-onset diabetes mellitus aimed at tight glucose control reduces the risk of micro- and macrovascular complications. Metabolic memory is a term used to describe beneficial effects of immediate intensive treatment of hyperglycemia and the observation that they are maintained for many years, regardless of glycemia in the later course of diabetes. This phenomenon was first observed in preclinical studies and was later confirmed in large clinical trials. It has been suggested that early glycemia normalization can halt hyperglycemia-induced pathological processes associated with enhanced oxidative stress and glycation of cellular proteins and lipids. The phenomenon of metabolic memory suggests that antioxidants and agents degrading advanced glycation end products in addition to strict hypoglycemic treatment can be used to prevent chronic diabetic complications.