GLP1R and type 2 diabetes mellitus: In the past decades, new hypoglycemic drugs have been continuously explored and have been administered to patients with T2DM, including dipeptidyl peptidase-4 inhibitors (DPP-4i), glucagon-like peptide 1 receptor agonists (GLP-1RA), and sodium-glucose cotransporter 2 inhibitors (SGLT-2i) (1).