Tirzepatide (Mounjaro™) is a single molecule that combines dual agonism of glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1) receptors. Tirzepatide is a GIP receptor and GLP-1 receptor agonist. It is a 39-amino-acid modified peptide with a C20 fatty diacid moiety that enables albumin binding and prolongs the half-life. Tirzepatide selectively binds to and activates both the GIP and GLP-1 receptors, the targets for native GIP and GLP-1. Tirzepatide enhances first- and second-phase insulin secretion, and reduces glucagon levels, both in a glucose-dependent manner. GIP also plays a role in nutrient and energy metabolism, while GLP-1 also delays gastric emptying, supresses appetite and improves satiety. Eli Lilly is developing tirzepatide for the treatment of type 2 diabetes mellitus (T2DM), obesity, cardiovascular disorders in T2DM, heart failure, non-alcoholic steatohepatitis, obstructive sleep apnoea and for reducing mortality/morbidity in obesity. In May 2022, tirzepatide received its first approval in the USA to improve glycaemic control in adults with T2DM, as an adjunct to diet and exercise. Tirzepatide is in phase III development for heart failure, obesity and cardiovascular disorders in T2DM, and in phase II development for non-alcoholic steatohepatitis. Tirzepatide can also be used off-label for treating obesity. It is currently implemented as a second-line diabetes medication, similar to GLP-1 medications like semaglutide. It is a once-a-week subcutaneous injectable medication with incremental dose increases.

Semaglutide (trade name Ozempic) is a pharmaceutical drug in development by a Danish company Novo Nordisk for the treatment of type 2 diabetes. Semaglutide is a once-daily glucagon-like peptide-1 analog that differs to others by the presence of an acyl group with a steric diacid at Lys26 and a large synthetic spacer and modified by the presence of a α-aminobutyric acid in position 8 which gives stability against the dipeptidylpeptidase-4. Semaglutide is a GLP-1 analogue with 94% sequence homology to human GLP-1. Semaglutide acts as a GLP-1 receptor agonist that selectively binds to and activates the GLP-1 receptor, the target for native GLP-1. GLP-1 is a physiological hormone that has multiple actions on glucose, mediated by the GLP-1 receptors. The principal mechanism of protraction resulting in the long half-life of semaglutide is albumin binding, which results in decreased renal clearance and protection from metabolic degradation. Furthermore, semaglutide is stabilized against degradation by the DPP-4 enzyme. Semaglutide reduces blood glucose through a mechanism where it stimulates insulin secretion and lowers glucagon secretion, both in a glucose-dependent manner. Thus, when blood glucose is high, insulin secretion is stimulated and glucagon secretion is inhibited. The mechanism of blood glucose lowering also involves a minor delay in gastric emptying in the early postprandial phase.