GLP1R and type 2 diabetes mellitus: Tirzepatide’s additional activation of the GIP receptor further amplifies its insulinotropic and metabolic effects. GLP-1RAs mimic the incretin hormone GLP-1 to enhance glucose-dependent insulin secretion, suppress glucagon release, delay gastric emptying, and reduce appetite through central nervous system pathways [21,22]. These mechanisms account for their robust effects on glycemic control and weight reduction in patients with T2D and obesity.