Dipeptidyl peptidase 4 (DPP4), also known as adenosine deaminase binding protein or cluster of differentiation 26 (CD26), is a serine exopeptidase able to inactivate various oligopeptides composed of proline, hydroxyproline, or alanine as the penultimate residue. In recent years, DPP4 has received attention due to its ability to rapidly inactivate the main incretins secreted by the gastrointestinal tract: glucagon-like peptide 1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP). As its own name already says, incretins enhance insulin secretion in a glucose-dependent fashion, but also suppress or modulate glucagon secretion. Since it was demonstrated that type 2 diabetes mellitus (T2D) have incretin deficiency and hyperglucagonemia on its physiopathology, gliptins emerged as a new class of drugs for the treatment of this disease, acting through the inhibition of DPP4 and consequently ameliorating these defects.