Evidence-Rated Research

Retatrutide Research

Every article is rated on the TruTide Evidence scale — from Phase 3 human trial data (A) to anecdotal reports (E) and unsupported claims (X). We show you the evidence quality, not just the headline.

Research & Evidence Desk

FDA Status Tracker

Approval status, regulatory pathway, compounding status, and date last verified

Clinical Trial Directory

TRIUMPH Phase 3 program — NCT IDs, phases, enrollment, and completion dates

Results & Evidence Timeline

Chronological timeline of peer-reviewed results, conference data, and regulatory announcements

Find a Clinical Trial

How to search ClinicalTrials.gov and enroll in an authorized trial

Glossary

28+ definitions: GLP-1, triple agonist, 503A/503B, RUO, Phase 3, and more

Source Library

Primary citations organized by category: FDA, journals, ClinicalTrials.gov, sponsor

Corrections & Update History

Transparent log of meaningful content changes with date, reason, and source

Evidence key:

AMay 2026Research

TRIUMPH-1 Phase 3 Results: Retatrutide Weight Loss at 80 Weeks

TRIUMPH-1 is a Phase 3 clinical trial evaluating once-weekly retatrutide in adults with obesity or overweight without diabetes. Eli Lilly reported topline results showing mean body-weight reductions of 19.0% (4 mg), 25.9% (9 mg), and 28.3% (12 mg) at 80 weeks. Lilly reported 2,339 randomized participants; ClinicalTrials.gov lists actual enrollment of 2,335. These are topline results; peer-reviewed publication is pending. Retatrutide remains investigational and is not FDA approved.

Eli Lilly and Company; ClinicalTrials.gov NCT05929066

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BJul 2026Research

Triple Agonism and Metabolic Rate: Mechanistic Findings from Phase 2 Extension

Phase 2 extension data suggest retatrutide's glucagon receptor activity contributes meaningfully to resting energy expenditure increases beyond what GLP-1 and GIP agonism alone produce.

Cell Metabolism

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CJun 2026Research

Glucagon Receptor Agonism and Lean Mass Preservation: What the Evidence Shows

Lean-mass preservation remains an important area of obesity-treatment research. Retatrutide's glucagon receptor activity provides a biologically interesting mechanism for continued study, but definitive conclusions about comparative lean-mass preservation require appropriate human body-composition data. Claims that retatrutide preserves more lean mass than semaglutide or another therapy are not supported by appropriate direct comparative evidence.

Jastreboff et al. (2023), New England Journal of Medicine; TRIUMPH-1 topline data (Eli Lilly, May 2026)

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AAug 2026Explainer

What Is Retatrutide? The Complete Guide to LY3437943

Retatrutide (LY3437943) is an investigational triple agonist developed by Eli Lilly targeting GLP-1, GIP, and glucagon receptors simultaneously — the first of its class to reach Phase 3 clinical development.

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AAug 2026Regulatory

FDA Confirms Retatrutide Cannot Be Compounded Under Federal Law

Retatrutide is an investigational drug and is not FDA approved. FDA has stated that retatrutide cannot be used in compounding under the federal exemptions in sections 503A and 503B of the Federal Food, Drug, and Cosmetic Act. There was no FDA shortage-based compounding authorization for retatrutide. Retatrutide remains investigational and there is currently no FDA-approved retatrutide product.

U.S. Food and Drug Administration

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