Compound research

Retatrutide: Research Overview & Current Status

By the Best Peptide Stores Editorial TeamLast reviewed 2026-08-08 · Also known as: LY3437943

In clinical trials

Retatrutide is a GIP/GLP-1/glucagon triple hormone receptor agonist. Current research status: in clinical trials. Retatrutide is in active Phase 3 development (TRIUMPH and TRANSCEND-T2D programs) and is not FDA-approved for any indication; it is not legally available as a prescription drug.

Overview

Retatrutide is an investigational peptide developed by Eli Lilly that acts as a triple agonist across the GIP, GLP-1, and glucagon receptors. It is being evaluated across a Phase 3 program (TRIUMPH) for obesity/overweight, type 2 diabetes, knee osteoarthritis, obstructive sleep apnea, and other metabolic indications, but has not received FDA approval.

GIP/GLP-1/glucagon triple hormone receptor agonist

Research timeline

2023
Eli Lilly's TRIUMPH Phase 3 program for retatrutide began, enrolling more than 5,800 participants across obesity/overweight, obstructive sleep apnea, and knee osteoarthritis registrational trials.
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2024
Phase 2a randomized trial reported retatrutide effects on metabolic dysfunction-associated steatotic liver disease (MASLD).
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2025-2026
TRIUMPH-1 (obesity/overweight), TRIUMPH-4 (obesity + knee osteoarthritis), TRIUMPH-3 (severe obesity + cardiovascular disease), and TRANSCEND-T2D-1 (type 2 diabetes) Phase 3 trials reported topline and detailed results.
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Active & recent research

Phase 3

TRIUMPH-1

weight loss efficacy and safety of retatrutide (4/9/12 mg) versus placebo in adults with obesity or overweight

NCT05929066 on ClinicalTrials.gov →Source →

Phase 3

TRIUMPH-4

weight loss and knee osteoarthritis pain/function in adults with obesity or overweight and knee osteoarthritis

NCT05931367 on ClinicalTrials.gov →Source →

Phase 3

TRIUMPH-3

weight loss in adults with severe obesity (Class 2/3) and established cardiovascular disease

NCT05882045 on ClinicalTrials.gov →Source →

Phase 3

TRANSCEND-T2D-1

A1C reduction and weight loss in adults with type 2 diabetes and inadequate glycemic control

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Key findings

TRIUMPH-4 reported that the highest retatrutide dose produced an average weight loss of 28.7% along with improvements in osteoarthritis pain and physical function at 68 weeks.
TRANSCEND-T2D-1 reported average A1C reductions of up to 2.0% and weight loss of up to 16.8% (36.6 lbs) at 40 weeks in adults with type 2 diabetes.
A Phase 2a randomized trial reported improvements in metabolic dysfunction-associated steatotic liver disease (MASLD) markers with retatrutide treatment.
Across TRIUMPH trials, gastrointestinal adverse events were reported as generally mild and infrequently led to discontinuation, consistent with the incretin drug class.

Safety & regulatory notes

Retatrutide is an investigational compound with no FDA approval and is not legally marketed for human use outside clinical trials. Reported adverse events in Phase 2/3 trials have been predominantly gastrointestinal (nausea, diarrhea, vomiting), consistent with other incretin-based therapies, but full long-term safety data are not yet established since Phase 3 trials remain ongoing or recently completed. Any product marketed as 'retatrutide' outside of Lilly's clinical trial program is an unapproved research chemical with unverified purity and no regulatory oversight.

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Where it's sold for research

We track vendor availability and published pricing for Retatrutide on a dedicated page. See where to buy Retatrutide →

Retatrutide FAQ

Is retatrutide FDA-approved?+

No. Retatrutide remains an investigational drug in Phase 3 clinical trials and has not received FDA approval for any indication.

What is retatrutide studied for?+

Lilly's TRIUMPH and TRANSCEND-T2D Phase 3 programs are studying retatrutide for obesity/overweight, type 2 diabetes, knee osteoarthritis, obstructive sleep apnea, chronic low back pain, cardiovascular/renal outcomes, and MASLD.

Is retatrutide legal to buy for research purposes?+

It is sold by some vendors as a research chemical labeled not for human use; because it remains investigational and unapproved, purity, dosing accuracy, and safety of such products are not verified by any regulatory body.

How does retatrutide differ from semaglutide and tirzepatide?+

Retatrutide targets three receptors (GIP, GLP-1, and glucagon) compared to semaglutide's single GLP-1 target and tirzepatide's dual GIP/GLP-1 target; Phase 3 trials have reported larger average weight-loss percentages for retatrutide, though it remains investigational and unapproved.

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