The 'other incretin' — the GIP receptor is the second half of GIP/GLP-1 dual agonists.
Also known as: glucose-dependent insulinotropic polypeptide · gastric inhibitory polypeptide
Part of the Metabolic & GLP-1 peptides cluster
Overview
GIP (glucose-dependent insulinotropic polypeptide) is a 42-amino-acid incretin hormone released from intestinal K-cells after meals, where it helps stimulate glucose-dependent insulin secretion. Long overshadowed by GLP-1, its receptor is now a deliberate target in dual-agonist peptides such as tirzepatide.
Source & context
Biological / chemical source: Intestinal K-cells
Primary research or clinical context: Endogenous hormone; one of the two receptors targeted by dual agonists like tirzepatide
Incretin biology
GIP and GLP-1 are the two classical incretins: gut hormones that amplify insulin release specifically when glucose is present. GIP is secreted by K-cells in the upper small intestine, while GLP-1 comes from L-cells further down. Together they explain why oral glucose triggers more insulin than the same glucose given intravenously.
From overlooked to central
For years GIP received far less attention than GLP-1. The success of GIP/GLP-1 dual agonists renewed interest in its receptor pharmacology, and GIP biology is now a core topic in metabolic peptide education. This page describes that physiology; it does not offer treatment guidance.
Sequence
One-letter sequence commonly cited for GIP (educational; isoforms and modifications may differ):
YAEGTFISDYSIAMDKIHQQDFVNWLLAQKGKKNDWKHNITQ
Residues plotted ~100° apart around an α-helix — clustering of one color reveals an amphipathic face.
FAQ about GIP
What is GIP?+
GIP (glucose-dependent insulinotropic polypeptide) is a 42-amino-acid incretin hormone released from intestinal K-cells after meals, where it helps stimulate glucose-dependent insulin secretion. Long overshadowed by GLP-1, its receptor is now a deliberate target in dual-agonist peptides such as tirzepatide.
Is GIP an approved medicine?+
GIP is discussed here as a research / educational topic. Endogenous hormone; one of the two receptors targeted by dual agonists like tirzepatide. This is not medical advice.
What is the typical length of GIP?+
GIP is commonly described as approximately 42 amino acids (Incretin).