Eli Lilly announced results on July 23, 2026 from two additional Phase 3 trials of retatrutide, its investigational triple-hormone-receptor agonist, expanding the drug's evidence base beyond the general-obesity population covered in the earlier TRIUMPH-1 trial. TRIUMPH-2 and TRIUMPH-3 each tested retatrutide in a more specific, higher-risk population, and both reported weight loss and metabolic results that were broadly consistent with, and in some cases larger than, what TRIUMPH-1 showed.
What TRIUMPH-2 Tested
TRIUMPH-2 enrolled adults with type 2 diabetes who also had obesity or were overweight, a population that historically loses less weight on incretin therapies than people without diabetes. According to Lilly's release, participants on the 4 mg dose lost an average of 12.7% of body weight (about 29.8 lbs) and saw A1C fall by 1.4 percentage points. At 9 mg, weight loss reached 19.1% (45.4 lbs) with a 1.6-point A1C reduction, and at the highest tested dose of 12 mg, average weight loss reached 20.8% (22.5 kg, or 49.6 lbs) alongside a 1.5-point A1C reduction.
What TRIUMPH-3 Tested
TRIUMPH-3 focused on adults with severe obesity who also had established cardiovascular disease, a group where weight-loss drug trials pay particularly close attention to cardiovascular safety signals alongside efficacy. Lilly reported that participants on the 9 mg dose lost an average of 21.6% of body weight (52.7 lbs), and those on 12 mg lost 22.6% (25.3 kg, or 55.8 lbs).
How This Fits With Retatrutide's Broader Program
Retatrutide is designed to activate three separate hormone receptors, GLP-1, GIP, and glucagon, an approach Lilly and outside researchers have argued could produce larger metabolic effects than drugs that act on GLP-1 alone or on two of the three receptors, such as tirzepatide. The site's earlier coverage of TRIUMPH-1's headline results and of how retatrutide compares with tirzepatide covers that broader context in more depth. TRIUMPH-2 and TRIUMPH-3 add evidence that the effect holds up, and in the cardiovascular-disease population may be even larger, in patients whose health profiles differ meaningfully from a general obesity trial population.
Regulatory Status
Retatrutide remains investigational and is not approved by the FDA for any use. Lilly has stated it intends to submit a Biologics License Application for retatrutide to the FDA in the first quarter of 2027, which would start, not finish, the formal review process; a filing does not guarantee approval or set a firm approval date. Readers curious about why some peptide drugs go through a Biologics License Application rather than the New Drug Application pathway used for semaglutide and tirzepatide can find that distinction explained in this site's guide to what a Biologics License Application is.
What the Data Does and Doesn't Show
These are large, randomized, controlled human clinical trials, the strongest form of evidence a drug can generate before approval, and both are meaningfully sized studies rather than small early-phase signals. That said, the results released so far come from a company announcement rather than a full peer-reviewed publication with complete safety tables, discontinuation rates, and adverse-event breakdowns, which typically follow later at a medical conference or in a journal. Longer-term safety and durability of weight loss beyond the trial period also remain open questions for any investigational drug at this stage, regardless of how strong the topline efficacy numbers look.
Anyone following retatrutide's development for its own health should treat trial results as evidence about a drug still under review, not as a treatment currently available by prescription, and should discuss any questions about diabetes or weight-loss treatment options that are actually FDA-approved with a licensed physician.