Comparing the next-generation triple agonist with the established GLP-1 standard
| Feature | Retatrutide | Semaglutide |
|---|---|---|
| Brand Names | LY3437943 (investigational) | Ozempic, Wegovy |
| Developer | Eli Lilly | Novo Nordisk |
| Mechanism | GLP-1 + GIP + Glucagon (triple) | GLP-1 only (single) |
| FDA Status | Not approved (Phase 3 trials) | FDA approved |
| Dosing Frequency | Once weekly | Once weekly |
| Starting Dose | 0.5 mg/week | 0.25 mg/week |
| Maximum Studied Dose | 12 mg/week | 2.4 mg/week |
| Weight Loss (Phase 2) | Up to ~24% body weight | ~15-16% body weight |
| Half-Life | ~6 days | ~7 days |
| Glucagon Component | Yes (increases energy expenditure) | No |
| Years of Safety Data | <3 years (trial data only) | 7+ years real-world data |
| Availability | Research suppliers only | Pharmacies + compounding |
Retatrutide represents a potential leap forward in incretin-based therapy by adding a third receptor target: the glucagon receptor. While semaglutide suppresses appetite through GLP-1 activation alone, retatrutide adds glucagon receptor agonism which may increase energy expenditure and fat oxidation on top of appetite reduction.
Phase 2 trial data showed participants on retatrutide achieved greater weight reduction compared to historical semaglutide results, though direct head-to-head trials have not been completed. The trade-off is that retatrutide has far less safety data and is not yet FDA approved.
Semaglutide remains the proven, FDA-approved option with extensive real-world safety data. Retatrutide shows promise but is still investigational. For most people, semaglutide or tirzepatide are the appropriate current choices. Retatrutide via research suppliers carries additional risks related to purity, dosing accuracy, and lack of medical oversight.
Need the broader GLP-1 reference set first? Start with the GLP-1 calculator hub, then move into the individual calculators and comparison pages.
Calculate your dose: Retatrutide calculator | Semaglutide calculator
This comparison is educational and should be read with product labeling, current clinical literature, and professional guidance where appropriate.