There are eight classes of oral drugs for diabetes (biguanides, sulfonylureas, glinides, α-glucosidase inhibitors, thiazolidinediones, DPP-4 inhibitors, and sodium-dependent glucose transporter 2 inhibitors (SGLT2i)) and two varieties of injectable agents (insulins and glucagon such as peptide-1 (GLP-1) receptor agonists (GLP-1RAs)). Here, INS is linked to diabetes mellitus.