What is GLP-1?
GLP-1 (glucagon-like peptide-1) is a hormone your gut releases after you eat. It's a peptide about 30 amino acids long that curbs appetite, slows stomach emptying, and improves the body's insulin response — but it breaks down within minutes.[1] A GLP-1 agonist (or GLP-1 receptor agonist) is a drug engineered to activate the same receptor while lasting far longer, turning a fleeting natural signal into a once-weekly or once-daily therapy.[2]
The complete list of GLP-1 drugs
Here are the GLP-1-based drugs, grouped by mechanism. "Agonist" means it activates the receptor.
| Drug | Brand(s) | Mechanism | Status |
|---|---|---|---|
| Semaglutide | Ozempic, Wegovy, Rybelsus | GLP-1 | Approved |
| Tirzepatide | Mounjaro, Zepbound | GIP + GLP-1 (dual) | Approved |
| Liraglutide | Victoza, Saxenda | GLP-1 | Approved |
| Dulaglutide | Trulicity | GLP-1 | Approved |
| Exenatide | Byetta, Bydureon | GLP-1 | Approved |
| Lixisenatide | Adlyxin | GLP-1 | Approved |
| Retatrutide | — | GIP + GLP-1 + glucagon (triple) | Phase 3 |
| Survodutide | — | GLP-1 + glucagon (dual) | Phase 3 |
| Mazdutide | — | GLP-1 + glucagon (dual) | Approved (China) |
| CagriSema | — | GLP-1 + amylin | FDA review |
| Amycretin | — | GLP-1 + amylin | Phase 3 |
See the full peptides for weight loss category, or the FDA-approved peptide drugs list.
Single, dual & triple agonists
The newest drugs don't just hit GLP-1 — they combine it with other gut hormones for a bigger effect:
- Single agonist (GLP-1 only): semaglutide, liraglutide, dulaglutide.
- Dual agonist: adds a second hormone. Tirzepatide adds GIP; survodutide and mazdutide add glucagon.
- Triple agonist: retatrutide hits GIP, GLP-1 and glucagon at once, and produced the largest weight loss yet in trials.[3]
As a rule, engaging more complementary pathways has translated into greater average weight loss — which is why the field has moved from single to dual to triple agonists.[2] Compare them directly: semaglutide vs tirzepatide, tirzepatide vs retatrutide.
Are GLP-1 drugs peptides?
Yes. Every drug in the table above is a peptide — a short chain of amino acids, engineered from the natural GLP-1 hormone. That's why they're injected (or, for a couple, specially formulated as tablets): peptides are broken down by digestion. This also distinguishes them from the newer oral small-molecule GLP-1 drugs in development, which are not peptides. For the full explanation, see is Ozempic a peptide?
Frequently asked questions
What is a GLP-1 agonist?
A GLP-1 agonist (or GLP-1 receptor agonist) is a drug that mimics GLP-1, a gut hormone that curbs appetite and improves insulin response. Engineered to last far longer than the natural hormone, these drugs — like semaglutide and tirzepatide — are used for type 2 diabetes and weight loss.
What are the GLP-1 drugs (list)?
Approved GLP-1 drugs include semaglutide (Ozempic, Wegovy, Rybelsus), liraglutide (Victoza, Saxenda), dulaglutide (Trulicity), exenatide (Byetta, Bydureon), lixisenatide (Adlyxin), and the dual GIP/GLP-1 agonist tirzepatide (Mounjaro, Zepbound). Retatrutide, survodutide, mazdutide, CagriSema, and amycretin are newer or pipeline agents.
Which GLP-1 drug is strongest for weight loss?
In trials, the triple agonist retatrutide has produced the largest average weight loss, followed by the dual agonist tirzepatide, then semaglutide, with older GLP-1 drugs like liraglutide producing less. Results are individual and retatrutide is still investigational.
Are GLP-1 drugs peptides?
Yes. Semaglutide, tirzepatide, and the other GLP-1 drugs are peptides — short chains of amino acids engineered from the natural GLP-1 hormone. That's why most are injected. Newer oral small-molecule GLP-1 drugs in development are not peptides.
What is the difference between a single, dual, and triple agonist?
A single agonist activates only the GLP-1 receptor (semaglutide). A dual agonist adds a second hormone — tirzepatide adds GIP; survodutide and mazdutide add glucagon. A triple agonist (retatrutide) hits GIP, GLP-1, and glucagon at once. More pathways has generally meant more weight loss.
Further reading
Selected peer-reviewed sources on this topic, labelled by type. A citation is a reference, not an endorsement.
- Baggio LL, Drucker DJ. Biology of incretins: GLP-1 and GIP. Gastroenterology. 2007. Peer-reviewed study
- Liu QK. Mechanisms of action and therapeutic applications of GLP-1 and dual GIP/GLP-1 receptor agonists. Front Endocrinol (Lausanne). 2024. Peer-reviewed study
- Wong HJ, Sim B, Teo YH, et al. Efficacy of GLP-1 Receptor Agonists on Weight Loss, BMI, and Waist Circumference: A Systematic Review and Meta-analysis of 47 Randomized Controlled Trials. Diabetes Care. 2025. Peer-reviewed study