Management of type 2 diabetes mellitus (DM) suggests the earliest therapy appointment. It is noted that in patients with DM type 2 the β-cell mass is reduced by more than 50%, and this reduction begins at the stage of pre-diabetes. The reducing of incretin effect can be observed at the stage of impaired glucose tolerance in the incensement of insulin concentration in response to oral intake of glucose and nutritional stimulus. Insulin secretion induced by glucagon-like peptide-1 in patients with type 2 DM is reduced in comparison with healthy people as a result of reduced functioning of β-cells mass. Thus, β-cell dysfunction is not only the step to developing type 2 DM, but also determines the continuing progressive course of the disease. This study indicates the possibility of improving incretin effect against the background of improved functional status of β-cells, for example, as a result of a removal of glucotoxicity. Drug preference is given to agents, simultaneously affecting several parts of pathogenesis and with the high level of safety. Dipeptidyl peptidase-4 inhibitors significantly restore β-cell mass and morphology of pancreatic islets, thus such function as insulin secretion has been persisting. This article describes the benefits of early application of dipeptidyl peptidase-4 inhibitors to correct the pathogenetic defects, as well as the development of new approaches to affect the incretin system.