Retatrutide Phase 3 Results: Triple Agonist Shows 24% Weight Loss at 48 Weeks

Eli Lilly has published Phase 3 clinical trial results for retatrutide, its investigational triple GIP/GLP-1/glucagon receptor agonist, demonstrating 24.2% mean weight loss at the 48-week primary endpoint. The results surpass current leading therapies and could reshape treatment expectations.

The Data

The TRUMPH-2 trial enrolled 2,100 adults with obesity (BMI ≥ 30) or overweight (BMI ≥ 27) with at least one weight-related comorbidity. Key findings include:

• 24.2% mean weight loss at the highest dose (12mg weekly) at 48 weeks
• 32% of participants achieved ≥ 30% weight loss, a threshold previously requiring bariatric surgery
• Significant improvements in blood pressure, HbA1c, and lipid panels
• Manageable safety profile with gastrointestinal side effects consistent with the GLP-1 receptor agonist class

How Retatrutide Differs

Unlike current GLP-1 therapies (semaglutide, tirzepatide) that target one or two incretin receptors, retatrutide is a triple agonist that simultaneously activates:

1. GLP-1 receptor — reduces appetite and slows gastric emptying
2. GIP receptor — enhances fat metabolism and insulin sensitivity
3. Glucagon receptor — increases energy expenditure

This triple mechanism is believed to account for the superior weight loss outcomes compared to dual agonists like tirzepatide.

Timeline to Market

Eli Lilly has indicated plans to submit a New Drug Application (NDA) to the FDA in Q3 2026. If approved, retatrutide could be available to patients by mid-2027, though supply constraints are expected during the initial launch period.

What Patients Should Know Now

Retatrutide is not yet FDA-approved and is not available through any telehealth provider. Patients should be cautious of any platform claiming to offer retatrutide or “generic retatrutide” — such products would be unapproved and potentially unsafe.

For patients currently on GLP-1 therapy, the retatrutide data reinforces that the incretin-based therapy class continues to evolve rapidly. Current medications like semaglutide and tirzepatide remain highly effective, well-studied options with established safety profiles.

Our retatrutide guide provides comprehensive coverage of this investigational therapy, and we will update it as new data becomes available.

Clinically reviewed by the GoGLP1 Editorial Team.