Retatrutide
A next-generation triple agonist targeting GLP-1, GIP, and glucagon receptors, showing unprecedented 24.2% weight loss in clinical trials. Expected FDA approval in 2027.
Also referenced as: LY3437943
This compound has a genuine development or study trail, but it is not an approved routine drug.
This profile is grouped by its dominant research and market lane, not by vendor shelf placement.
LY3437943
FDA label signal · 34 trials · 131 PubMed results
What is Retatrutide?
Retatrutide is Eli Lilly’s next-generation obesity drug — a triple agonist that simultaneously targets three receptors: GLP-1, GIP, and glucagon. While semaglutide (Ozempic/Wegovy) hits one receptor and tirzepatide (Mounjaro/Zepbound) hits two, retatrutide hits all three. The result? Record-setting weight loss in clinical trials.
How It Works
The triple agonism provides three distinct mechanisms:
- GLP-1 receptor: Suppresses appetite, slows gastric emptying, improves insulin sensitivity
- GIP receptor: Enhances insulin secretion, may improve fat metabolism
- Glucagon receptor: Increases energy expenditure, promotes fat oxidation, lowers fasting glucose
The glucagon component is the key differentiator. While GLP-1 and GIP primarily reduce calorie intake, glucagon actively increases calorie burning — essentially attacking obesity from both sides.
Clinical Trial Results
Phase 2 data showed 24.2% average body weight loss at the highest dose (12mg) over 48 weeks. To put that in perspective:
- Semaglutide (Wegovy): ~15% weight loss
- Tirzepatide (Zepbound): ~22.5% weight loss
- Retatrutide: ~24.2% weight loss
The TRIUMPH Phase 3 program has enrolled 3,000+ participants across multiple trials.
Current Status
Retatrutide is not yet FDA approved. Eli Lilly has targeted an NDA filing in late 2026, with an expected FDA decision in 2027. Currently, access is limited to compounding pharmacies at a cost of approximately $200-500/month.
Side Effects
The side effect profile is similar to other GLP-1 agonists but slightly more pronounced:
- Nausea (most common, usually subsides with dose titration)
- Diarrhea
- Decreased appetite
- Vomiting
- Slightly elevated heart rate (due to glucagon component)
The Bottom Line
Retatrutide represents the cutting edge of obesity pharmacology. If the Phase 3 data holds up, it will likely become the most effective FDA-approved weight loss drug on the market. For those willing to access it through compounding ahead of approval, the cost savings are significant — but you’re accepting more risk with less long-term safety data.