An important and efficacious group of T2DM therapeutics includes a group of peptides such as insulin analogues, and, more recently, incretin mimetics, acting as either agonists (e.g., Glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP) analogues) or antagonists (e.g., GLP-1 receptor antagonists) of endogenous human hormones, with modifications [15]. Here, GCG is linked to type 2 diabetes mellitus.