Retatrutide (LY3437943) — Research Literature Summary

Regulatory notice — research reference only

Retatrutide is an investigational compound in Phase 3 clinical trials (TRIUMPH program). It is NOT FDA-approved for any indication and is NOT available through any legitimate compounding or prescribing pathway in the United States. This page describes published clinical-trial dose arms for educational reference only. Not for human use.

Published research summary

• Retatrutide (LY3437943) is an Eli Lilly investigational triple agonist at the GIP, GLP-1, and glucagon receptors. It is a 39-amino-acid peptide with a C20 fatty diacid conjugation conferring albumin binding and a half-life of approximately 6 days (weekly subcutaneous dosing).
• In the Phase 2 obesity trial (Jastreboff et al., NEJM 2023;389:514-526, PMID 37366315), weekly subcutaneous retatrutide up to 12 mg produced approximately 24% mean body weight reduction at 48 weeks among participants with obesity. In the Phase 2 T2D study (Rosenstock et al., Lancet 2023;402:529-544, PMID 37385280), HbA1c reductions of up to 2.02% were reported.
• The TRIUMPH Phase 3 program includes trials in obesity, obesity with cardiovascular disease, obesity with osteoarthritis, MASH, and heart failure. No Phase 3 efficacy or safety results have been published as of April 2026.
• Phase 2 safety signals reported to date include dose-related gastrointestinal adverse events, gallbladder events, heart rate increase (up to ~7 bpm at higher doses), premature ventricular contractions, and standard incretin-class signals (pancreatitis, hypersensitivity). Long-term hepatic safety with chronic glucagon receptor agonism has not been established. The GLP-1 class-wide thyroid C-cell tumor signal (based on rodent studies) applies pending further data.

Why this page does not publish a consumer “cycle” schedule

Retatrutide is investigational. There is no FDA-approved dose, no approved indication, no approved compounding pathway, and no approved prescribing pathway for retatrutide in any jurisdiction as of this writing. Any dosing schedule would represent off-label extrapolation from published trial arms.

Peer-reviewed citations

1. Jastreboff AM, et al. Triple-Hormone-Receptor Agonist Retatrutide for Obesity - A Phase 2 Trial. NEJM 2023;389:514-526. PMID 37366315.
2. Rosenstock J, et al. Retatrutide, a GIP, GLP-1 and glucagon receptor agonist, for people with type 2 diabetes: a Phase 2 trial. Lancet 2023;402:529-544. PMID 37385280.
3. Sanyal AJ, et al. Triple hormone receptor agonist retatrutide for metabolic dysfunction-associated steatotic liver disease. Nature Medicine 2024;30:2037-2048. PMID 38858523.
4. ClinicalTrials.gov - TRIUMPH program (retatrutide, Phase 3).

Consulting a healthcare provider: This page is a reference for published research. If you are considering any health decision, consult a licensed healthcare provider. Path to Peptides does not provide medical advice.