The GLP-1 Class Explained
The full GLP-1 class — mechanisms, clinical results, and how to pick.
"GLP-1 drug" has become shorthand for a whole generation of weight loss medicine. This is the class guide — what the receptors actually do, which drugs target which, and how the next-gen agonists fit in.
The class, in one table
| Generation | Receptors targeted | Representative drugs |
|---|---|---|
| Single agonist | GLP-1 | Semaglutide (Ozempic, Wegovy, Rybelsus), liraglutide, orforglipron (oral) |
| Dual agonist | GLP-1 + GIP | Tirzepatide (Mounjaro, Zepbound) |
| Dual agonist | GLP-1 + glucagon | Survodutide, mazdutide, pemvidutide |
| Dual agonist | GLP-1 + amylin | CagriSema (cagrilintide + semaglutide), amycretin |
| Triple agonist | GLP-1 + GIP + glucagon | Retatrutide ("GLP-3") |
What each receptor does
- GLP-1. Cuts appetite, boosts insulin after meals, slows gastric emptying.
- GIP. Amplifies insulin release, may modulate fat metabolism. Adding it to GLP-1 is what let tirzepatide beat semaglutide.
- Glucagon. Increases energy expenditure and fat breakdown. The calorie-burning side of the equation.
- Amylin. Different hormone family; strengthens satiety. CagriSema pairs an amylin analog with semaglutide.
Approval status (US, early 2026)
| Drug | For weight loss | For type 2 diabetes |
|---|---|---|
| Semaglutide | Approved (Wegovy) | Approved (Ozempic, Rybelsus) |
| Tirzepatide | Approved (Zepbound) | Approved (Mounjaro) |
| Orforglipron (Foundayo) | Approved Apr 2026 | Approved |
| Liraglutide | Approved (Saxenda) | Approved (Victoza) |
| Retatrutide | Phase 3 | Phase 3 |
| CagriSema | Phase 3 | Phase 3 |
| Survodutide | Phase 3 | Phase 3 |
| Mazdutide | Approved in China | Phase 3 elsewhere |
For the decision framework — which one is best for you — start with Which GLP-1 Drug Is Best for Weight Loss?. For every head-to-head we've published, see comparisons.
All glp-1 guide articles
8 articles
GLP-1 Drug Comparison Tool: Compare Weight Loss Drugs Side by Side
Interactive comparison tool for GLP-1 weight loss drugs. Select 2-3 drugs to compare mechanism, efficacy, cost, and status.
Updated February 2026
GLP-1 Drugs and Mental Health: What the Evidence Actually Shows
The FDA cleared GLP-1 drugs of psychiatric risk after reviewing 91 trials. The surprising finding: these drugs may actually improve depression.
Updated March 2026
GLP-1 vs GLP-2 vs GLP-3: What's the Difference?
GLP-1 and GLP-2 are real hormones. "GLP-3" is not — it's slang for retatrutide. Here's what each term actually means.
Updated February 2026
Mounjaro vs Ozempic: Which Is Better for Weight Loss and Diabetes?
Mounjaro produced twice the weight loss of Ozempic in head-to-head trials. Practical comparison of cost, insurance, and prescribing differences.
Updated February 2026
Ozempic vs Wegovy: Same Drug, Different Purpose
Ozempic and Wegovy both contain semaglutide. The difference: indication (diabetes vs weight loss), max dose (2.0 vs 2.4 mg), and insurance coverage.
Updated February 2026
Tirzepatide vs Semaglutide: Complete Comparison (2026 Data)
Tirzepatide vs semaglutide with SURMOUNT-5 head-to-head data: -20.2% vs -13.7% weight loss. Full comparison of efficacy, side effects, and access.
Updated February 2026
Which GLP-1 Drug Is Best for Weight Loss? (2026 Guide)
Decision framework for choosing the best GLP-1 drug: by max weight loss, CV protection, oral option, diabetes control, or liver fat.
Updated February 2026
Zepbound vs Wegovy: Which Weight Loss Drug Is Better?
Zepbound produced -20.2% vs Wegovy's -13.7% weight loss in the SURMOUNT-5 head-to-head trial. Full comparison of cost, side effects, and CV data.
Updated February 2026