The short version
- TRIUMPH-1 and TRIUMPH-2 test retatrutide 4, 9 and 12 mg once weekly against placebo; TRIUMPH-3 and TRIUMPH-4 test 9 and 12 mg. Together they enrolled more than 5,800 participants.
- Every TRIUMPH arm uses 16 weeks of fixed dose escalation and 64 weeks of maintenance, with the primary weight endpoint at week 80 (week 68 in TRIUMPH-4).
- The registry lists all four TRIUMPH trials as completed (primary completion November 2025 to June 2026); peer-reviewed results had not been published as of September 2026.
- TRANSCEND-T2D-1, the first phase 3 paper (Lancet, June 2026), used 4, 9 and 12 mg for 40 weeks in 537 adults with type 2 diabetes.
The phase 3 doses: 4, 9 and 12 mg
The phase 3 program narrowed the retatrutide ladder to three maintenance doses. The TRIUMPH design paper (Giblin and colleagues, Diabetes, Obesity and Metabolism, 2025) states it in one sentence: "TRIUMPH-1 and TRIUMPH-2 evaluate retatrutide in doses of 4, 9 and 12 mg and placebo comparator given subcutaneously once weekly, while TRIUMPH-3 and TRIUMPH-4 are evaluating retatrutide in weekly doses of 9 and 12 mg and placebo comparator." The diabetes trial TRANSCEND-T2D-1 used the same 4, 9 and 12 mg set. The 1 mg and 8 mg doses from phase 2 were not carried forward, and 0.5 mg was dropped from the diabetes program.
Phase 3 tests three doses: 4, 9 and 12 mg a week. The 8 mg dose from phase 2 was dropped.
Why 4, 9 and 12?
The papers give the method rather than the arithmetic. The Lancet phase 2 diabetes paper ends its interpretation with "these phase 2 data also informed dose selection for the phase 3 programme", and the TRIUMPH paper says doses and escalation "were selected based on safety and efficacy data as well as exposure-response modelling from phase 1 and 2 retatrutide studies".
What the phase 2 data showed is on the record: 8 mg and 12 mg produced near-identical results on HbA1c (-1.99 and -2.02), on weight in diabetes (16.81% and 16.94%) and on liver fat (81.4% and 82.4%), while in obesity 12 mg added 1.4 points over 8 mg at 48 weeks. A 9 mg arm sits in the flat part of that curve with a wider margin below the ceiling; that reading is this site's inference, not a quotation. The per-dose numbers are in the results page.
The four TRIUMPH trials
| Trial | Registry | Population | Doses (weekly) | Enrolled | Primary endpoint |
|---|---|---|---|---|---|
| TRIUMPH-1 | NCT05929066 | obesity or overweight, no type 2 diabetes; OSA and knee OA baskets | 4, 9, 12 mg vs placebo (1:1:1:1) | 2,335 | % weight change, week 80; AHI and WOMAC pain in baskets |
| TRIUMPH-2 | NCT05929079 | type 2 diabetes with obesity or overweight; OSA basket | 4, 9, 12 mg vs placebo (1:1:1:1) | 1,152 | % weight change, week 80; AHI in basket |
| TRIUMPH-3 | NCT05882045 | severe obesity with established cardiovascular disease | 9, 12 mg vs placebo (1:1:2) | 1,946 | % weight change, week 80 |
| TRIUMPH-4 | NCT05931367 | obesity or overweight with knee osteoarthritis | 9, 12 mg vs placebo (1:1:1) | 445 | WOMAC pain and % weight change, week 68 |
The program is a "basket" design: TRIUMPH-1 and TRIUMPH-2 nest obstructive sleep apnoea and knee osteoarthritis sub-studies inside the weight-management trials, so one randomisation serves several questions, with the type I error split across them.
The registry entries give the enrolment figures above and describe every retatrutide arm as "administered SC"; the design paper describes the trials as running in 13 countries, with all participants receiving individual lifestyle counselling alongside drug or placebo. Note the 4 mg dose appears only in TRIUMPH-1 and TRIUMPH-2, and the trials in populations with cardiovascular disease and osteoarthritis test the two higher doses only.
Escalation and maintenance in phase 3
Every TRIUMPH arm follows the same shape: a "fixed dose escalation regimen" of 16 weeks, then maintenance at the assigned dose for 64 weeks (52 in TRIUMPH-4), then a 4-week safety follow-up. The design paper does not print the intermediate steps of the 16-week climb, and this site does not fill that gap with a guess.
It does print the exceptions: a permanent dose reduction is allowed for gastrointestinal events or inadequate oral intake that persist after a de-escalation and re-escalation attempt, and for participants who reach a BMI of 22 or below or perceive excessive weight loss.
Compared with phase 2, where escalation was completed by week 12, the phase 3 climb is a third longer. The titration evidence that motivated the change is in the titration guide, and the schedules of every trial are laid out in the dosing schedule guide.
TRANSCEND-T2D-1: the first phase 3 results
The diabetes program runs under the TRANSCEND name, and its first trial is the first retatrutide phase 3 paper in print: Bajaj and colleagues, The Lancet, June 2026. 537 adults with type 2 diabetes on diet and exercise alone were randomised to 4, 9 or 12 mg once weekly or placebo for 40 weeks. HbA1c fell 1.69, 1.86 and 1.94 percentage points (placebo 0.81) and weight fell 11.5%, 13.9% and 15.3% (placebo 2.6%).
Discontinuation for adverse events was 2 to 5% with retatrutide and 0% with placebo, with no severe hypoglycaemia. The registry entry (NCT06354660) confirms the four arms and completed status. The diabetes dose picture across phase 2 and 3 is in the type 2 diabetes dose guide.
Status, and what is still pending
As of September 2026 the registry lists TRIUMPH-4 with primary completion in November 2025, TRIUMPH-1 in April 2026, TRIUMPH-3 in April 2026 and TRIUMPH-2 in June 2026, all marked completed. Their peer-reviewed publications have not appeared.
That means the largest and longest retatrutide dose data, 80 weeks at 4, 9 and 12 mg in thousands of people, is not yet citable, and any figure attributed to TRIUMPH that lacks a DOI should be treated as a press report until the paper exists. This page will carry the numbers, dose by dose, when a journal prints them. Until then the dose range with published human data remains 0.5 to 12 mg, summarised on the retatrutide dosage guide.
Questions readers ask
What doses are used in the retatrutide phase 3 trials?
4, 9 and 12 mg once weekly in TRIUMPH-1, TRIUMPH-2 and TRANSCEND-T2D-1; 9 and 12 mg in TRIUMPH-3 and TRIUMPH-4. All subcutaneous, all compared with placebo.
Why did phase 3 drop the 8 mg dose?
The Lancet phase 2 authors state their data informed phase 3 dose selection, and the TRIUMPH design paper says doses and escalation were chosen from phase 1 and 2 safety, efficacy and exposure-response modelling. The papers do not print the specific reasoning for 9 rather than 8 mg.
How long are the TRIUMPH trials?
80 weeks of treatment (16 weeks of escalation plus 64 of maintenance) for TRIUMPH-1, 2 and 3, and 68 weeks for TRIUMPH-4, each followed by a 4-week safety period. A TRIUMPH-1 subset continues to week 104.
Have the TRIUMPH results been published?
Not in a peer-reviewed journal as of September 2026. The registry marks the trials completed. This site adds numbers only when they carry a DOI.
Sources
Reviewed against the primary sources on 21 Sep 2026. Every DOI resolves on CrossRef and every NCT number on ClinicalTrials.gov.
- Giblin A, et al. Retatrutide for the treatment of obesity, obstructive sleep apnea and knee osteoarthritis: Rationale and design of the TRIUMPH registrational clinical trials. Diabetes, Obesity and Metabolism. 2025;28:83-93. doi.org/10.1111/dom.70209
- ClinicalTrials.gov. TRIUMPH-1: retatrutide once weekly in participants without type 2 diabetes who have obesity or overweight. Phase 3; 2,335 participants; primary endpoint at week 80. clinicaltrials.gov/study/NCT05929066
- ClinicalTrials.gov. TRIUMPH-2: retatrutide once weekly in participants with type 2 diabetes who have obesity or overweight. Phase 3; 1,152 participants; primary endpoint at week 80. clinicaltrials.gov/study/NCT05929079
- ClinicalTrials.gov. TRIUMPH-3: retatrutide once weekly in participants with severe obesity and established cardiovascular disease. Phase 3; 1,946 participants; primary endpoint at week 80. clinicaltrials.gov/study/NCT05882045
- ClinicalTrials.gov. TRIUMPH-4: retatrutide once weekly in participants with obesity or overweight and knee osteoarthritis. Phase 3; 445 participants; primary endpoints at week 68. clinicaltrials.gov/study/NCT05931367
- Bajaj HS, Welch M, Shah P, et al. Efficacy and safety of retatrutide, a GIP, GLP-1, and glucagon receptor agonist, in people with type 2 diabetes and inadequate glycaemic control with diet and exercise (TRANSCEND-T2D-1): a double-blind, randomised, phase 3 trial. The Lancet. 2026;407(10546):2402-2413. doi.org/10.1016/S0140-6736(26)00967-0
- ClinicalTrials.gov. TRANSCEND-T2D-1: retatrutide once weekly compared with placebo in adults with type 2 diabetes on diet and exercise alone. Phase 3; 537 participants; 40 weeks. clinicaltrials.gov/study/NCT06354660
- Rosenstock J, Frias J, Jastreboff AM, et al. Retatrutide, a GIP, GLP-1 and glucagon receptor agonist, for people with type 2 diabetes: a randomised, double-blind, placebo and active-controlled, parallel-group, phase 2 trial conducted in the USA. The Lancet. 2023;402(10401):529-544. doi.org/10.1016/S0140-6736(23)01053-X