GIP

A 42-amino-acid incretin hormone secreted by intestinal K-cells in response to fat and carbohydrate ingestion. Stimulates glucose-dependent insulin secretion from pancreatic β-cells and exerts anabolic effects on bone and adipose tissue. The GIP receptor (GIPR) is the second target of tirzepatide alongside the GLP-1 receptor, and the co-activation of both receptors is believed to contribute to tirzepatide's superior efficacy vs pure GLP-1 agonists in head-to-head clinical trials.