Pharmacology · Class
GLP-1 receptor agonists !
Injected (and one oral) drugs that copy the gut hormone GLP-1: more insulin after meals, less appetite, weight loss.
Updated 2026-11-01
What they are
Incretin mimetics resistant to DPP-4. Used in type 2 diabetes, obesity and to lower cardiovascular risk.
Mechanism of action
They activate the GLP-1 receptor, a class B G-protein-coupled receptor linked to Gs and cAMP. In beta cells this boosts insulin release only when glucose is high (glucose-dependent); in alpha cells it lowers glucagon. They also slow gastric emptying and act on the hypothalamus and brainstem to reduce appetite. Natural GLP-1 lasts minutes because DPP-4 cuts it; the drugs are protected by amino-acid changes, fatty-acid chains or fusion to large proteins.
Target: GLP-1 receptor (GLP1R), class B GPCR
Drugs in this class
- SemaglutideA long-acting GLP-1 agonist, weekly by injection or daily by mouth: strong glucose lowering, large weight loss and…GLP-1 receptor (GLP1R)
- LiraglutideA once-daily injected GLP-1 agonist for type 2 diabetes and, at other doses, obesity. It raises insulin after meals…GLP-1 receptor (GLP1R)
- DulaglutideA weekly injected GLP-1 agonist fused to an antibody fragment. It lowers glucose and cardiovascular events in type 2…GLP-1 receptor (GLP1R)
- TirzepatideA weekly injection that activates both GIP and GLP-1 receptors: large falls in glucose and weight. Used in type 2…GIP receptor and GLP-1 receptor (dual agonist)
- ExenatideThe first GLP-1 agonist: a synthetic copy of exendin-4, a peptide from Gila monster saliva. Injected twice a day, or…GLP-1 receptor (GLP1R)
Others in the class
- lixisenatide
Test yourself
Think of the answer, then tap the question to see it.
Why do GLP-1 agonists rarely cause hypoglycemia on their own?
Their effect on insulin release is glucose-dependent: when glucose falls toward normal, the extra insulin release stops.
Which personal or family history rules out a GLP-1 agonist?
Medullary thyroid carcinoma or multiple endocrine neoplasia type 2 (MEN 2).
How does a GLP-1 agonist differ from a DPP-4 inhibitor?
The agonist gives drug levels far above natural GLP-1 and causes weight loss; a DPP-4 inhibitor only protects the body's own incretins, has a smaller effect and is weight-neutral.
Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given.
Sources: Semaglutide Injection: MedlinePlus Drug Information (MedlinePlus (U.S. National Library of Medicine), 2026); DailyMed - LIRAGLUTIDE injection, solution (DailyMed (U.S. National Library of Medicine), 2026); Semaglutide-bound Glucagon-Like Peptide-1 (GLP-1) Receptor in Complex with Gs protein (RCSB Protein Data Bank, 2021).
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Representative model, for educational purposes only.