A 39 amino acid peptide and synthetic version of exendin-4, a hormone found in the saliva of the venomous lizard Gila monster, with insulin secretagogue and antihyperglycemic activity. Exenatide is administered subcutaneously and mimics human glucagon-like peptide-1 (GLP-1). Compared to GLP-1, exenatide has a longer half-life of 2.4 hours.