Is retatrutide FDA approved?

No. Retatrutide is still in Phase 3 clinical trials (TRIUMPH program by Eli Lilly). It is not yet available by prescription. Expected FDA submission may come in late 2026 or 2027 pending trial results.

How does retatrutide compare to tirzepatide?

Retatrutide is a triple agonist (GIP + GLP-1 + glucagon) while tirzepatide is a dual agonist (GIP + GLP-1). Phase 2 data shows retatrutide may produce greater weight loss (24.2% vs 22.5%) though head-to-head trials have not been completed.

What makes retatrutide different from other weight loss peptides?

Retatrutide is the first triple-hormone receptor agonist, adding glucagon receptor activation to the GIP/GLP-1 mechanism. The glucagon component increases energy expenditure and promotes liver fat burning, which may explain the unprecedented weight loss results.

Content reviewed by clinical research staff

Last reviewed: March 2026Sources: PubMed, FDA, WADA Prohibited List

Evidence graded using the PeptideScholar A-D system

Retatrutide

BHuman Studies

Triple GIP/GLP-1/Glucagon receptor agonist · 39 amino acids

Not FDA ApprovedPrescription Required

Retatrutide is an investigational triple-hormone receptor agonist developed by Eli Lilly. It simultaneously targets GIP, GLP-1, and glucagon receptors, achieving the highest weight loss ever reported in an obesity clinical trial — up to 24.2% at 48 weeks.

Mechanism of Action

Activates three metabolic receptors simultaneously: GIP receptors (enhances insulin secretion and fat metabolism), GLP-1 receptors (reduces appetite and slows gastric emptying), and glucagon receptors (increases energy expenditure and hepatic lipid oxidation). The triple agonism produces additive metabolic benefits beyond dual agonists.

Benefits

Unprecedented 24.2% weight loss in Phase 2 trials
Superior to both semaglutide and tirzepatide in early data
Significant liver fat reduction (NAFLD/MASH benefit)
Improved glycemic control in type 2 diabetes

Not Medical Advice — Research-Reported Information Only

This content is for informational purposes only and does not constitute medical advice.

Retatrutide — Dosing in Published Research

Reported Routes: Subcutaneous injection

Phase 2 trial tested doses of 1, 4, 8, and 12 mg SC weekly. Phase 3 trials (TRIUMPH program) ongoing with expected completion in 2026.

The dosing information above is sourced from published research literature and clinical trials. These are not recommendations. Individual responses vary. Always consult a healthcare provider before considering any peptide-based therapy.

Side Effects

Nausea, vomiting, diarrhea (dose-dependent)
Decreased appetite
Constipation
Injection site reactions
Long-term safety profile still being established

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Research & Evidence

RCTNew England Journal of Medicine, 2023

Retatrutide Once Weekly for Treatment of Obesity

Retatrutide produced dose-dependent weight loss of up to 24.2% at 48 weeks — the highest ever reported in an obesity trial

PMID: 37385275

RCTNew England Journal of Medicine, 2023

Retatrutide for Type 2 Diabetes

Retatrutide reduced HbA1c by up to 2.16% and body weight by up to 16.94% in adults with type 2 diabetes

PMID: 37840095

Compare Retatrutide With

Retatrutide vs Tirzepatide

Retatrutide vs Semaglutide

Retatrutide vs Survodutide

References

1. Retatrutide Once Weekly for Treatment of Obesity. New England Journal of Medicine, 2023. “Retatrutide produced dose-dependent weight loss of up to 24.2% at 48 weeks — the highest ever reported in an obesity trial” [PMID: 37385275]
2. Retatrutide for Type 2 Diabetes. New England Journal of Medicine, 2023. “Retatrutide reduced HbA1c by up to 2.16% and body weight by up to 16.94% in adults with type 2 diabetes” [PMID: 37840095]

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Retatrutide FAQ

Medical Disclaimer

This content is for informational and educational purposes only and does not constitute medical advice, diagnosis, or treatment recommendations.

Always consult a qualified healthcare provider before starting, stopping, or modifying any treatment. Do not disregard professional medical advice based on information found on this site.

No claims of therapeutic efficacy are made for substances that are not FDA-approved for the discussed indications. Research citations reflect published findings and do not imply endorsement.

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