DPP-4 (Dipeptidyl Peptidase-4)

Deep dive

DPP-4 (Dipeptidyl Peptidase-4): complete reference

Dipeptidyl peptidase-4 (DPP-4) is a serine exopeptidase enzyme expressed on cell surfaces throughout the body, with particularly high concentrations on T cells, kidney brush border, and capillary endothelium. Its primary metabolic role is the rapid degradation of incretins — GLP-1 and GIP — within 1-2 minutes of their release from gut L-cells and K-cells. DPP-4 cleaves the N-terminal dipeptide of these hormones, rendering them inactive. This rapid degradation explains why native GLP-1 has such a brief biological half-life and is the rationale for two distinct therapeutic strategies: (1) DPP-4 inhibitors (sitagliptin, linagliptin, saxagliptin) that prolong native incretin activity, and (2) DPP-4-resistant GLP-1 receptor agonists (semaglutide, tirzepatide, liraglutide) that mimic incretin signaling for hours to days. DPP-4 inhibitors are weight-neutral oral diabetes medications; GLP-1 receptor agonists produce substantial weight loss because they activate receptors at supra-physiologic levels.

In practice

When you take Wegovy (semaglutide), the molecule is structurally modified to resist DPP-4 cleavage — that's why it lasts a week instead of 2 minutes like your body's natural GLP-1.

Clinical context

DPP-4 inhibitors are weight-neutral; GLP-1 agonists produce weight loss. Patients sometimes confuse the two classes — they target the same pathway differently.