Peptide Science
What Is a GLP-1 Receptor Agonist?
The incretin axis, why native GLP-1 lasts only minutes, and how modern analogues are engineered to survive far longer.
August 12, 2026 · 7 min read · Novanta Research
The native hormone
Glucagon-like peptide-1 is an incretin hormone released by intestinal L-cells after a meal. It acts on a G protein-coupled receptor found in the pancreas, gut, and several regions of the brain, raising cyclic AMP in the cells that express it.
Native GLP-1 is degraded within a couple of minutes by the enzyme dipeptidyl peptidase-4, which clips the first two residues from the N-terminus. That short half-life is the central engineering problem every analogue solves.
How analogues extend duration
Two strategies dominate. The first is substitution at the DPP-4 cleavage site so the enzyme can no longer recognise the sequence. The second is attaching a fatty acid chain, which lets the molecule bind circulating albumin and act as a slow-release reservoir.
Combining both gives the long-duration profiles seen in contemporary research compounds, and it is why those sequences differ noticeably from the native hormone.
Single, dual and triple agonists
A single agonist engages the GLP-1 receptor alone. Dual agonists add the GIP receptor. Triple agonists add glucagon receptor activity on top of that, which is why retatrutide is often described in the literature as a GLP-3 class compound.
Each added receptor changes the pharmacology, not just the potency, because the three receptors sit on different tissues and feed different downstream programmes.
Research status
Compounds in this class supplied by Novanta are research chemicals. They are not approved for human or veterinary use, and nothing on this site should be read as clinical guidance.
Frequently asked
- What does GLP-3 mean?
- It is shorthand used in the research market for triple-agonist compounds that engage the GIP, GLP-1 and glucagon receptors — retatrutide being the best-known example. It is not a distinct native hormone.
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For laboratory and research use only. Not for human or veterinary consumption. Novanta Research is not a compounding pharmacy and nothing in this article is medical advice or a claim that any compound diagnoses, treats, cures or prevents any condition.