GIP

Glucose-Dependent Insulinotropic Polypeptide (GIP 1-42)

Evidence & Status

  • Strong Human Evidence
  • Strong

At a Glance

An endogenous incretin hormone secreted after meals that stimulates insulin release, though its effect is blunted in type 2 diabetes. GIP receptor biology underlies the design of tirzepatide, a separate FDA-approved dual-agonist drug; this entry describes native GIP itself, not that drug's clinical outcomes.

Plain English

Researchers study GIP (Glucose-dependent Insulinotropic Polypeptide) because it's one of two major gut hormones, alongside GLP-1, that help control insulin release after eating. In people with type 2 diabetes, GIP's ability to trigger insulin release is reduced compared to people without diabetes. Scientists found that combining GIP-receptor activation with GLP-1-receptor activation — as the drug Tirzepatide does — produces added metabolic benefits; but those clinical results belong to Tirzepatide as a distinct drug, not to native GIP itself.

Overview

Glucose-dependent insulinotropic polypeptide (GIP) is a 42-amino-acid incretin hormone (calculated MW ≈4,983.6 Da) secreted by duodenal and jejunal K-cells in response to nutrient ingestion. Like GLP-1, it stimulates glucose-dependent insulin secretion from pancreatic beta-cells; its receptor (GIPR) is also expressed in adipose tissue, bone, and the CNS. In a clamp study, IV native GIP stimulated insulin secretion in both healthy controls and people with type 2 diabetes (Meier et al., 2004), though a separate randomized-order infusion study found GIP's insulinotropic effect is markedly impaired in type 2 diabetes and does not potentiate GLP-1's effect when combined (Nauck et al., 2011). GIP was historically deprioritized for diabetes drug development because of this blunted effect, but its receptor is now co-targeted (alongside GLP-1R) by tirzepatide, an FDA-approved dual agonist. This entry describes native, endogenous GIP; tirzepatide's clinical trial outcomes are a property of that separate, distinct drug product and are not carried in this record.

Research Summary

Native GIP's insulinotropic physiology is well documented in direct human studies: IV GIP stimulates insulin secretion in both healthy volunteers and people with type 2 diabetes, though its effect is markedly blunted in type 2 diabetes, and it does not potentiate GLP-1's glucose-lowering effect when co-infused. This blunted native activity is why GIP was historically deprioritized as a monotherapy target. The discovery that GIPR agonism in adipose tissue can enhance GLP-1 receptor sensitivity motivated development of tirzepatide, a distinct FDA-approved dual GIP/GLP-1 receptor agonist drug; tirzepatide's own clinical trial results (e.g., SURPASS, SURMOUNT) describe that separate drug product and are documented in its own entry, not transferred here to native GIP.

Research Areas

  • Insulin secretion
  • Adipose tissue metabolism
  • Bone metabolism
  • GLP-1 receptor sensitization
  • Cardiovascular effects

Safety & Risks

Serious Risks

  • Not applicable as a standalone compound; see Tirzepatide entry for therapeutic risk profile

Reported Side Effects

  • At supraphysiologic infusion levels: mild nausea, modest gastric effects
United States
Endogenous hormone — not an approved drug itself; its receptor (GIPR) is targeted by tirzepatide (Mounjaro/Zepbound), a separate FDA-approved dual GIP/GLP-1 agonist
United Kingdom
Not a licensed drug; see the Tirzepatide entry for that drug's own regulatory status
Australia
Not a therapeutic product; see the Tirzepatide entry for that drug's own regulatory status
Canada
Not a drug; see the Tirzepatide entry for that drug's own regulatory status

Citations & Sources