Retatrutide Shows 28% Weight Loss in Phase 3 Trial

Nearly half of participants receiving the highest dose achieved at least 30% body weight reduction.

By
Kathryn Wighton
May 21, 2026
2 min

MDSpire News

Objective:

To evaluate the efficacy and safety of retatrutide, a triple hormone receptor agonist, in adults with obesity or overweight and at least one weight-related comorbidity.

Key Findings:

Participants on retatrutide 12 mg experienced a mean body weight reduction of 28.3% (70.3 pounds).
45.3% of participants on 12 mg achieved at least 30% body weight reduction.
65.3% of participants on 12 mg achieved a BMI below 30 by week 80.
At 104 weeks, participants on 12 mg had a mean weight reduction of 30.3% (85.0 pounds).
Retatrutide treatment led to reductions in waist circumference, triglycerides, systolic blood pressure, and other health markers.

Interpretation:

Retatrutide demonstrates significant weight loss and health improvements in adults with obesity, with a favorable efficacy profile compared to placebo.

Limitations:

Adverse events were primarily gastrointestinal, with discontinuation rates higher in retatrutide groups compared to placebo.
Long-term safety and efficacy data beyond 104 weeks are still pending.