Body Composition · Metabolic
Retatrutide
Also known as: LY3437943
An investigational triple agonist of GIP, GLP-1, and glucagon receptors in late-stage clinical trials for obesity and related conditions.
Sign in to add to watchlistEvidence strength
Strength of human clinical evidence — A (strongest) to D (mostly preclinical). This reflects research maturity, not safety or suitability.
Vial Theory provides educational research summaries only. Content is not medical advice, diagnosis, treatment, dosing guidance, or individualized suitability screening. Regulatory status can change over time and varies by jurisdiction.
Key Takeaways
- ›Retatrutide is an investigational triple agonist (GIP + GLP-1 + glucagon) given once weekly.
- ›Phase 2 trials reported some of the largest average weight reductions seen in obesity research.
- ›It is not approved; Phase 3 (TRIUMPH) confirmation across several conditions is ongoing.
- ›Gastrointestinal effects and increased heart rate were reported; long-term safety is not established.
- ›Gray-market 'retatrutide' is unregulated. Speak with a licensed healthcare professional before any decisions.
What It Is
Retatrutide is a synthetic peptide engineered to activate three incretin-family receptors simultaneously: the GIP receptor, the GLP-1 receptor, and the glucagon receptor. The compound is fatty-acid acylated for albumin binding and once-weekly dosing in clinical investigation. Its triple-agonist design is the most pharmacologically distinct feature relative to dual agonists like tirzepatide and selective GLP-1 agonists like semaglutide.
The rationale for adding glucagon receptor agonism is that glucagon increases energy expenditure and may augment hepatic lipid handling, potentially contributing to weight loss and metabolic effects beyond what GIP/GLP-1 dual agonism produces. Calibrating the relative receptor activity to capture metabolic benefits without destabilizing glucose control is one of the central design challenges, and the published Phase 2 program reported on this balance.
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Disclaimer: This content is for educational and research purposes only and is not medical advice. Always consult a licensed healthcare professional before making health-related decisions.