GIP

Definition

Glucose-dependent Insulinotropic Polypeptide (GIP), also known as gastric inhibitory polypeptide, is a 42-amino-acid incretin hormone secreted by K-cells in the duodenum and jejunum in response to nutrient ingestion, particularly fats and carbohydrates.

Mechanism and Physiological Role

GIP binds the GIP receptor (GIPR), a G protein-coupled receptor expressed on pancreatic beta cells, adipocytes, bone cells, and neurons. Its primary metabolic function is potentiating glucose-dependent insulin secretion — it enhances insulin release only when blood glucose is elevated, providing a built-in safety mechanism against hypoglycaemia.

Beyond insulin secretion, GIP signalling influences lipid metabolism, bone turnover, and central appetite regulation. GIP is rapidly inactivated by dipeptidyl peptidase-4 (DPP-4), giving it a circulating half-life of approximately 5–7 minutes.

Relevance to Peptide Research

GIP receptor agonism is a key component of dual and triple incretin-based therapies. Tirzepatide, a dual GIP/GLP-1 receptor agonist, has demonstrated significant efficacy in glucose control and weight management studies. The “twincretin” approach — combining GIP and GLP-1 receptor activation — represents one of the most active areas of metabolic peptide research. Retatrutide extends this further as a triple agonist targeting GIP, GLP-1, and glucagon receptors.

Related Peptides

Peptide profiles that reference “GIP” in their research content.