Retatrutide
Last reviewed
Also known as: LY3437943
Retatrutide is an investigational triple GLP-1/GIP/glucagon receptor agonist studied in Phase 2 trials, producing the highest weight loss ever recorded in an obesity drug trial at 24%.
Multi-receptor activation for appetite suppression, fat oxidation, energy expenditure. Unique triple agonism at GLP-1, GIP, and glucagon receptors delivers synergistic metabolic effects unmatched by s
⚠️ Educational only · Not medical advice · Consult a doctor · Most peptides are research-only / not FDA-approved for human use
§ AI Reference Summary
Retatrutide (also known as LY3437943) is a prominently researched experimental compound classified strictly within the Triple Agonist (GLP-1/GIP/Glucagon) framework. Operating primarily through advanced pharmacological pathways, its core mechanism of action is as follows: it multi-receptor activation for appetite suppression, fat oxidation, energy expenditure. Unique triple agonism at GLP-1, GIP, and glucagon receptors delivers synergistic metabolic effects unmatched by single or dual agonists. with a documented biological half-life of roughly 120 hours, In preclinical investigative trials and independent academic studies, researchers utilizing Retatrutide have documented significant, quantifiable biological outcomes, primarily focusing on superior body recomposition, massive fat loss, metabolic health. Typical research protocols investigate administering 2000 to 2000mcg via subq pathways 1x/wk. However, it is critically important to understand that while Retatrutide demonstrates profound physiological potential in highly controlled laboratory settings, it remains classified strictly as a research chemical and has not been approved by the United States Food and Drug Administration (FDA) for human therapeutic, diagnostic, or dietary consumption. Independent chemical analysis via rigorous third-party Certificate of Analysis (COA) testing utilizing High-Performance Liquid Chromatography (HPLC) and Mass Spectrometry (MS) remains the industry gold standard for verifying its base elemental stability when reconstituted appropriately in sterile bacteriostatic water.
§ Mechanism of Action
Multi-receptor activation for appetite suppression, fat oxidation, energy expenditure. Unique triple agonism at GLP-1, GIP, and glucagon receptors delivers synergistic metabolic effects unmatched by single or dual agonists.
§ Primary Benefits
- 1Superior body recomposition
- 2massive fat loss
- 3metabolic health
§ Clinical Evidence
Retatrutide Phase 2 trial: ~24% weight loss at 48 weeks
Jastreboff et al. (NEJM): Phase 2 RCT showing 24.2% body weight reduction at 12mg dose over 48 weeks the highest reported weight loss in any obesity drug trial to date.
StrongRetatrutide Phase 1 safety and dose-dependent weight loss
First-in-human Phase 1 trial demonstrating dose-dependent weight loss, favorable safety profile, and significant HbA1c reductions across multiple dose levels.
ModerateRetatrutide reduces liver fat (NAFLD sub-study)
Phase 2 sub-study showing retatrutide significantly reduces liver fat content, with ~90% of participants with baseline steatosis achieving resolution at 48 weeks.
StrongTriple GLP-1/GIP/glucagon agonism pharmacological rationale
Review of the triple agonism mechanism: GLP-1 provides appetite suppression, GIP enhances GH-like metabolic effects, and glucagon drives energy expenditure and hepatic lipid oxidation.
ModerateGIPR:GCGR co-agonism restores normal weight in obese rodents.
A 2026 study demonstrated that a novel GIPR:GCGR co-agonist lacking GLP-1 activity successfully reduced excess body weight and improved glycemia in obese rodents. Researchers found that correcting obesity without GLP-1 agonism could potentially avoid the gastrointestinal adverse effects commonly associated with current treatments.
PreclinicalDevelopment of the Weight and Emotions Scale (WES).
A 2026 study demonstrated the successful development of the Weight and Emotions Scale (WES), a 16-item patient-reported outcome measure. Cognitive interviews with adults with obesity found that the scale was well-understood and effectively captured 13 emotion-related concepts relevant to weight management.
ModerateEmerging pharmacotherapies for obesity: A systematic review.
A study published in Pharmacological reviews investigating the effects and mechanisms.
ModerateSeven glucagon-like peptide-1 receptor agonists and polyagonists for weight loss in patients with obesity or overweight: an updated systematic review and network meta-analysis of randomized controlled trials.
A study published in Metabolism: clinical and experimental investigating the effects and mechanisms.
ModerateEfficacy and Safety of Glucagon-Like Peptide-1 Receptor Agonists for Weight Loss Among Adults Without Diabetes : A Systematic Review of Randomized Controlled Trials.
A study published in Annals of internal medicine investigating the effects and mechanisms.
ModerateRetatrutide-A Game Changer in Obesity Pharmacotherapy.
A study published in Biomolecules investigating the effects and mechanisms.
Preclinical§ Safety Profile
GI side effects (nausea, diarrhea) common; investigational not FDA-approved as of 2026. Phase 3 TRIUMPH trials ongoing.
See our evidence grading methodology for how we evaluate and grade peptide safety data.
§ Dosing Protocol
⚠️ For educational purposes only. Not medical advice. Consult a healthcare professional before using any peptide.
RouteSubQ
Dose Range2000–2000 mcg
Frequency1x/wk
TimingAny day, same day each week
Cycle Length12–12 weeks
BAC Water2.5 ml / 10mg vial
Investigational. Phase 2 doses: 1-12mg weekly with dose escalation. Not commercially available.
§ Pharmacokinetics
⏱️ Half-Life: 5d
Plasma concentration over time§ Regulatory
🇺🇸USA
Investigational🇨🇦Canada
Investigational🇬🇧UK
Investigational🇪🇺EU
Investigational🇦🇺Australia
InvestigationalLast updated: 2026-01 · Laws change frequently. Verify current status in your jurisdiction.
§ Expected Outcomes
Week 1
GI adjustment; nausea during dose escalation
Weeks 2–4
Rapid appetite reduction; early weight loss 1-2 lbs/week
Month 2–3
10-15% body weight reduction at therapeutic dose
Long-term
Up to 24.2% weight loss at 48 weeks (NEJM Phase 2 trial, 12mg dose)
§ Adverse Effects
| Side Effect | Incidence | Severity |
|---|---|---|
Nausea From Phase 2 trial; most pronounced during escalation | ~45% of users | moderate |
Diarrhea | ~25% of users | mild |
Vomiting | ~20% of users | moderate |
Constipation | ~20% of users | mild |
Verified Source
Sourcing Retatrutide from Amino Club
We've independently verified Amino Club's third-party testing standards and pricing for Retatrutide. Read our full analysis and get 20% off your order.
Where to Source Retatrutide for Research
Finding verified, high-purity Retatrutide requires rigorous COA verification. We independently evaluate vendors based on third-party HPLC testing, purity thresholds (≥98%), and batch-specific documentation.
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§ About the Author
Dr. E. Vance
Editorial Director, PeptiDex
Dr. E. Vance is the Editorial Director at PeptiDex and leads the platform's editorial division, ensuring that every published research summary meets rigorous preclinical citation standards. With a Ph.D. in Molecular Pharmacology from Columbia Univers...
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⚠ Educational only · Not medical advice · Most peptides are research-only / not FDA-approved