GLP and GIP Peptides Explained: Incretin Biology for Researchers
GLP-1 and GIP are gut hormones called incretins. This guide explains the biology behind them and why so many analogs and dual-receptor peptides are studied.
Key takeaways
- GLP-1 and GIP are incretin hormones released by the gut after eating.
- Native incretins are broken down within minutes by the enzyme DPP-4, so analogs are engineered for longer activity.
- Approved medicines in this area are prescribed by clinicians; research peptides are not interchangeable with them.
The incretin system
GLP-1 (glucagon-like peptide-1) is secreted by L-cells in the intestine, and GIP (glucose-dependent insulinotropic polypeptide) is secreted by K-cells. Both are released after a meal and act on receptors in tissues including the pancreas, where they enhance insulin secretion in response to glucose. Together they are called incretins.
Why analogs exist
Native GLP-1 has a half-life of only a couple of minutes because the enzyme DPP-4 cleaves it rapidly. To make it useful as a research tool, chemists design analogs. Common strategies include substituting amino acids at the cleavage site and attaching a fatty acid chain that promotes binding to albumin, both of which lengthen the time the peptide remains active.
Single, dual and related agonists
- GLP-1 receptor agonists act on one receptor. Liraglutide, an acylated GLP-1 analog, is an example.
- Dual agonists act on two receptors, for example GLP-1 with glucagon receptors or GLP-1 with GIP receptors. Survodutide and mazdutide are studied as GLP-1 and glucagon receptor co-agonists.
- Amylin analogs such as cagrilintide act on a different hormone system and are often studied alongside incretins.
Research versus medicine
Several molecules in this family are approved medicines, made under pharmaceutical standards and prescribed by clinicians for specific conditions. Research-grade peptides are a different category of product. They are sold for laboratory investigation only, and this guide does not offer medical advice, dosing or human-use guidance.
Choosing well-documented material
These are long, modified sequences, so identity and purity are harder to achieve than with short peptides. Look for batch-specific data: see how to read a certificate of analysis. Browse the GLP and GIP Peptides collection to see what is listed.