Tirzepatide

Tirzepatide is a dual-action synthetic peptide that mimics two hormones the gut naturally produces after eating: GLP-1 (glucagon-like peptide-1) and GIP (glucose-dependent insulinotropic polypeptide). Unlike single-agonist peptides that only target GLP-1, tirzepatide activates both receptors simultaneously. It was developed by Eli Lilly and Co. and approved by the FDA in 2022 under the brand name Mounjaro for type 2 diabetes, and later as Zepbound for weight management. Research-grade tirzepatide is sold strictly for in-vitro laboratory research and is not for human use.

GLP-1 receptor agonists have been studied since the 1990s as potential treatments for type 2 diabetes. Eli Lilly researchers developed tirzepatide as a "twincretin" - a molecule that could activate both GLP-1 and GIP receptors in a single injection, potentially offering better glycemic control and greater weight reduction than GLP-1 alone. Clinical trials (SURPASS program) showed remarkable results for both blood sugar control and weight loss in subjects with type 2 diabetes.

After eating, your intestines release GLP-1 and GIP hormones that signal the pancreas to release insulin and tell the brain you're full. In people with type 2 diabetes, these signals are often weakened or ignored. Tirzepatide acts as a synthetic stand-in for both hormones at once - attaching to their receptors and sending stronger-than-natural signals. The result in clinical subjects with type 2 diabetes has been improved insulin release after meals, reduced appetite signaling, and significant weight reduction. Research models study these mechanisms in detail to understand the underlying biology.