Retatrutide
Reviewed by Fat Man in the Arena · Updated March 2026
Key Takeaway
Retatrutide is a triple hormone receptor agonist (GIP/GLP-1/glucagon) currently in Phase 3 clinical trials. Early data shows up to 24% body weight loss, potentially making it the most effective weight loss peptide ever studied.
How it works
Retatrutide activates three receptors simultaneously: GIP, GLP-1, and glucagon. The addition of glucagon receptor activation increases energy expenditure and fat oxidation beyond what dual agonists achieve, creating a three-pronged approach to weight loss.
Benefits
- Up to 24.2% weight loss in Phase 2 trials
- Potentially the most effective weight loss compound studied
- Triple receptor action for enhanced fat burning
- Significant reduction in liver fat
- Improved metabolic markers across the board
Side effects
- Nausea
- Diarrhea
- Vomiting
- Constipation
- Similar GI profile to other GLP-1 agonists
Dosing protocol
Typical Dose
1 mg to 12 mg weekly (Phase 2 doses)
Frequency
Once weekly subcutaneous injection
Not yet FDA-approved. Dosing based on Phase 2 trial data. Phase 3 trials are underway with results expected in 2026.
Key research
Triple-Hormone-Receptor Agonist Retatrutide for Obesity (Phase 2)
New England Journal of Medicine (2023) — PubMed
At the 12 mg dose, participants lost 24.2% of body weight over 48 weeks. This is the largest weight loss ever reported for any anti-obesity medication in clinical trials.
Frequently asked questions
Retatrutide is currently in Phase 3 clinical trials conducted by Eli Lilly. Based on typical regulatory timelines, FDA approval could come in late 2026 or 2027 if Phase 3 results are positive. The compound is not yet available by prescription or through compounding pharmacies.
Compare Retatrutide
Goals
Related peptides
Weekly peptide research updates
New studies, GLP-1 news, protocol insights, and weight loss data — delivered every week. Free. No spam.
Medical Disclaimer: This content is for informational and educational purposes only. It is not intended as medical advice or a substitute for professional medical consultation, diagnosis, or treatment. Always consult a qualified healthcare provider before starting any peptide protocol.