Retatrutide TRIUMPH-2 Results Explained (EASD 2026)
On September 30, 2026, Eli Lilly presented the full results of TRIUMPH-2, a Phase 3 trial of retatrutide in adults with type 2 diabetes and obesity or overweight, at the EASD annual meeting in Milan. The study was published the same week in The Lancet. The short version: it worked, on both weight and blood sugar, in a group of patients for whom weight loss is usually harder.
Key facts
- Who: 1,152 adults with type 2 diabetes and obesity or overweight, across 8 countries. Average BMI 38.2.
- How long: 80 weeks, once-weekly injection, three doses (4 mg, 9 mg, 12 mg) vs placebo.
- Weight: up to 20.8% average weight loss (about 49.6 lbs) at 12 mg, vs 4.0% on placebo, among people who stayed on treatment.
- Blood sugar: A1C fell by up to 1.6 points, and up to 40% of participants reached an A1C below 5.7%, the non-diabetic range.
- Status: retatrutide is not FDA-approved. Lilly plans to submit it to the FDA in the first quarter of 2027.
Why this result matters
People with type 2 diabetes typically lose less weight on GLP-1 medicines than people without diabetes. That pattern held here too: TRIUMPH-1, in people without diabetes, reached 28.3% at the top dose among people who stayed on treatment, the same basis as the 20.8% here. But 20.8% in a diabetes population is a strong number, and it came with a large drop in A1C at the same time.
By the end of the study, 59.5% of participants on 12 mg no longer met the BMI definition of obesity. Among those who started with a BMI of 35 or higher, the 12 mg group lost an average of 23.4% (about 60.8 lbs).
The numbers, by dose
Lilly reports two ways of measuring the result. The “efficacy” figure counts people who stayed on the drug as planned; the “treatment-regimen” figure includes everyone, including those who stopped. Both are honest; they answer different questions.
| Dose | Weight loss (on treatment) | Weight loss (everyone randomized) |
|---|---|---|
| 4 mg | 12.7% (29.8 lbs) | 11.9% |
| 9 mg | 19.1% (45.4 lbs) | 16.8% |
| 12 mg | 20.8% (49.6 lbs) | 18.8% |
| Placebo | 4.0% | 5.1% |
A1C fell by 1.4 to 1.6 points across the three doses, vs 0.2 points on placebo.
Side effects, plainly
The side-effect profile looked like the GLP-1 class: mostly digestive, mostly early, mostly during dose increases.
- Diarrhea 27 to 34% (placebo 13%) and nausea 14 to 28% (placebo 8%).
- Dysesthesia, an unusual skin sensation such as tingling or sensitivity to touch, in 4 to 7% (placebo 1%). This has appeared across the retatrutide program, more at higher doses, and researchers are still characterizing it.
- Low blood pressure in 1 to 6% (placebo under 1%).
- Stopping because of side effects: 4 to 12% (placebo 5%).
These are averages from a supervised trial with slow dose increases. That is part of why this is a medicine to start and adjust with a clinician.
What it means for you
Nothing changes at the pharmacy yet. Retatrutide is investigational, and no legitimate pharmacy can fill a prescription for it today. Products sold online as “research retatrutide” are not the medicine tested in these trials. For the realistic timeline, see When will retatrutide be available?. For how it compares with what you can get now, see Retatrutide vs tirzepatide vs semaglutide.
If you have type 2 diabetes and are thinking about weight medicines, the drugs that are approved today (tirzepatide and semaglutide) are worth a conversation with a licensed provider now. You can also track every regulatory change on our legal status tracker.
Sources
- Pharmacy Times: Retatrutide cuts weight up to 18.8% in adults with T2D, obesity (TRIUMPH-2, The Lancet)
- Eli Lilly: new data on retatrutide at EASD 2026
- ClinicalTrials.gov: NCT05929079 (TRIUMPH-2)
- BioPharma Dive: Lilly to seek FDA approval of retatrutide (Jul 23, 2026)
Educational content only, not medical advice. Retatrutide is an investigational medicine and is not FDA-approved.