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Retatrutide

In Clinical Trials

GLP-1 Receptor Agonists · Weight Management

Retatrutide is an investigational triple-action peptide that activates GLP-1, GIP, and glucagon receptors simultaneously.

What is Retatrutide?

Retatrutide is an investigational triple-action peptide that activates GLP-1, GIP, and glucagon receptors simultaneously. In Phase 2 trials, it produced unprecedented weight loss of up to 24.2% at 48 weeks, making it potentially the most effective anti-obesity peptide ever studied.

Also known as: LY3437943, triple G agonist

How Does Retatrutide Work?

Simultaneously activates three incretin-related receptors: GLP-1 (appetite suppression, insulin secretion), GIP (enhanced insulin sensitivity, fat metabolism), and glucagon (increased energy expenditure, hepatic fat reduction). This triple agonism produces synergistic effects on weight loss and metabolic health.

What is Retatrutide Used For?

  • Obesity treatment
  • Type 2 diabetes
  • NASH/MAFLD

Potential Side Effects

  • Nausea
  • Diarrhea
  • Vomiting
  • Constipation
  • Decreased appetite

Contraindications

  • Not yet approved - investigational only

FDA Legal Status

United States — FDA

In Clinical Trials

This peptide is currently investigational and not approved for clinical use.

Related Peptides

Semaglutide

FDA Approved

GLP-1 Receptor Agonists

Semaglutide is a glucagon-like peptide-1 (GLP-1) receptor agonist used for type 2 diabetes management and chronic weight...

Tirzepatide

FDA Approved

GLP-1 Receptor Agonists

Tirzepatide is a first-in-class dual GIP and GLP-1 receptor agonist used for type 2 diabetes and chronic weight manageme...

Head-to-head comparisons:

Retatrutide vs Semaglutide

Frequently Asked Questions

When will retatrutide be approved?
Retatrutide is currently in Phase 3 clinical trials. If successful, FDA approval could come in late 2026 or 2027. Eli Lilly has not announced a specific timeline.
How much weight loss does retatrutide cause?
In Phase 2 trials, the highest dose (12mg) produced 24.2% body weight loss at 48 weeks — more than any other anti-obesity medication tested to date.
How is retatrutide different from semaglutide?
Semaglutide activates only GLP-1 receptors, while retatrutide activates three receptors (GLP-1, GIP, and glucagon). This triple agonism may produce greater weight loss and additional metabolic benefits including liver fat reduction.

Quick Facts

Legal Status (USA)
In Clinical Trials
Evidence Rating
BModerate Evidence (Some Human Data)
Class / Subclass
GLP-1 Receptor Agonists / Weight Management
Administration
subcutaneous
Typical Dosage
1mg–12mg weekly (Phase 2 dosing)
Half-Life
~6 days
Year Discovered
2021

Sources

PubMed 37385275NCT05929066

Last updated: 2026-04-01

Sources & references

Primary sources used for the dosing, mechanism, side-effect, and regulatory claims on this page. Verify time-sensitive information (regulatory status, prescribing details) on the source before relying on it for medical decisions. See our disclaimer.

  1. PubMed PMID 37385275 — peer-reviewed primary literature on Retatrutide.
  2. ClinicalTrials.gov NCT05929066 — registered clinical trial; protocol, dosing, and outcome reporting per FDA / NIH standards.
  3. FDA Federal Register — official notice record for FDA regulatory actions and Category 1 / 503A bulk-substance updates.