Retatrutide Research Guide — Triple GIP/GLP-1/Glucagon Agonist

## Introduction

Retatrutide (LY-3437943) is an investigational triple receptor agonist representing the next frontier in incretin-based metabolic research. Developed by Eli Lilly, this synthetic peptide simultaneously activates GIP, GLP-1, and glucagon receptors—adding a third mechanism absent in dual agonists. Phase 2 data demonstrated up to 24.2% mean body weight reduction at 48 weeks, exceeding any previously studied incretin compound.

With 77 PubMed-verified studies, retatrutide is supplied as high-purity research material (≥98%) for laboratory investigation only.

## Mechanism of Action

Retatrutide’s triple receptor agonism provides three distinct axes of metabolic action.

**GIP Receptor Activation:** Enhances glucose-dependent insulin secretion, promotes adipose tissue remodeling, improves energy partitioning.

**GLP-1 Receptor Activation:** Glucose-dependent insulin secretion, glucagon suppression, delayed gastric emptying, central appetite suppression.

**Glucagon Receptor Activation:** The key differentiating feature. Increases hepatic energy expenditure through enhanced fatty acid oxidation, stimulates thermogenesis in brown adipose tissue, and promotes lipolysis.

## Research Applications

**Phase 2 Data (NCT04881760):** Up to 24.2% mean body weight reduction at 48 weeks. Marked reductions in liver fat content, HbA1c improvements, and favorable lipid profile changes.

**Current Status:** Phase 3 development underway (ATTAIN for obesity, ACHIEVE for T2D). Research-grade material is for laboratory studies only.

## Dosage & Administration

Phase 2 titration: 1mg → 2mg → 4mg → 6mg → 9mg → 12mg at 4-week intervals. SubQ once weekly.

## Reconstitution Guide

Reconstitute with 1-2mL bacteriostatic water. Swirl gently. Store at 2-8°C; use within 30 days.

## Safety & Side Effects

Common: nausea, vomiting, diarrhea, constipation. Dose-dependent. Mild increase in heart rate (2-4 bpm). No clinically significant hypoglycemia.

## References

- PeptideWiki

- PubMed: 77+ studies

- Phase 2 trial (NCT04881760)