Retatrutide reports 28.3% mean weight loss in phase 3 TRIUMPH-1
Eli Lilly’s topline results show all three doses of the GIP/GLP-1/glucagon triple agonist met their endpoints at 80 weeks in adults with obesity or overweight without diabetes. The 12 mg dose produced a mean 28.3% weight loss, and 45.3% of participants lost at least 30% of body weight.
EVIDENCE
Human RCT · topline
WHY IT MATTERS
These are the largest average losses yet seen with a medicine at phase 3 scale, approaching what surgery achieves. The figures are company-reported; we will update this page when the full paper is peer-reviewed.
The details
TRIUMPH-1 randomized 2,339 adults to retatrutide 4 mg, 9 mg or 12 mg, or placebo, escalating every four weeks. Absolute losses at 80 weeks were 21.4 kg, 29.2 kg and 31.9 kg on the three doses, versus 2.5 kg on placebo, and no weight-loss plateau was seen by the end of the trial.
Results from TRIUMPH-2 (obesity with type 2 diabetes) and TRIUMPH-3 (established cardiovascular disease) are expected later in 2026. Retatrutide is not FDA-approved and should only be used inside a clinical trial.
PRIMARY SOURCE
Eli Lilly press release, May 21, 2026; presented at the ADA Scientific Sessions, June 2026
TRIUMPH-1 · NCT05929066
Educational summary only. It is not medical advice and does not replace a conversation with your clinician.