What is the current state of retatrutide evidence?
The distinction between a completed trial and a published trial does more work here than anywhere else in this library. A trial is 'completed' when the last participant has finished the last scheduled visit. Its results become citable evidence only when they are posted to the registry as structured data, or published in a peer-reviewed journal where independent reviewers have examined the methods and analysis. Several TRIUMPH trials have reached the first milestone. Two, TRIUMPH-1 and TRIUMPH-2, had reached the second by 14 October 2026. [12][13]
Press releases and conference presentations frequently report topline figures ahead of publication. Those figures are not peer-reviewed and are not cited as evidence in this library.
What did the published phase 2 trials find?
HUMAN — PHASE 2 RANDOMISED TRIALS
| Study design | Detail |
|---|---|
| Participants | 338 adults with obesity |
| Duration | 48 weeks, with the primary endpoint at 24 weeks |
| Arms | Four retatrutide dose groups versus placebo |
| Primary endpoint | Percent change in body weight at 24 weeks |
| Endpoint | Result |
| Weight change at 48 weeks | −8.7%, −17.1%, −22.8% and −24.2% across the four dose groups |
| Placebo at 48 weeks | −2.1% |
| Most common adverse events | Gastrointestinal, generally dose-related |
The 48-week figures above are the ones usually quoted, but the trial's primary endpoint was measured at 24 weeks. That distinction matters because a primary endpoint is pre-specified and the trial is statistically sized to detect it; later timepoints are secondary and carry more uncertainty, partly because more participants have discontinued by then. Both sets of numbers are real; only the 24-week result carries the trial's full statistical weight. [1]
A second phase 2 trial studied retatrutide in people with type 2 diabetes and was published in The Lancet in 2023. It used a different population and different endpoints from the obesity trial, so its results should not be merged with them. [2]
Phase 2 exists to identify which doses are worth carrying forward, not to establish a treatment. A 338-participant trial cannot characterise uncommon adverse events, and 48 weeks cannot describe what happens over years.
What is the TRIUMPH phase 3 programme?
HUMAN — PHASE 3, TRIUMPH-1 AND TRIUMPH-2 PUBLISHED; OTHERS ONGOING [12][13]
TRIUMPH is the name given to retatrutide's phase 3 development programme. Phase 3 trials are large, long, and designed to confirm effects seen in phase 2 in populations closer to real-world use. The table below records each registered trial with the enrolment figure and status shown on ClinicalTrials.gov when checked on September 18, 2026.
| Trial | Registry ID | Enrolment | Status |
|---|---|---|---|
| TRIUMPH-1 | NCT05929066 | 2,335 actual | Completed |
| TRIUMPH-2 | NCT05929079 | 1,152 actual | Completed |
| TRIUMPH-3 | NCT05882045 | 1,946 actual | Completed |
| TRIUMPH-4 | NCT05931367 | 445 actual | Completed |
| TRIUMPH-5 | NCT06662383 | 800 estimated | Active, not recruiting |
| TRIUMPH-Outcomes | NCT06383390 | 10,000 estimated | Active, not recruiting |
| TRIUMPH-6 (weight maintenance) | NCT06859268 | 643 estimated | Active, not recruiting |
Two entries in that table deserve separate mention. TRIUMPH-5 is registered with tirzepatide as an active comparator, which would make it the first head-to-head trial between the two compounds if and when results are published. TRIUMPH-Outcomes is a cardiovascular outcomes trial with an estimated enrolment of 10,000, the kind of study that takes years to accumulate enough events to analyse. [6][7]
A design and rationale paper for the TRIUMPH programme was published in Diabetes, Obesity and Metabolism in 2025. A design paper describes how trials were planned and what they will measure; it does not report what they found. [10]
For the receptor biology behind the programme, see How does retatrutide work?.
How should these registry records be read?
ClinicalTrials.gov is a public registry where sponsors are required to record trials before they begin and update them as they progress. That pre-registration is what makes it valuable: it creates a record of what a trial intended to measure, before anyone knows the answer, which makes it much harder to quietly change the endpoint after the fact.
Registry fields carry specific meanings. 'Estimated' enrolment is a target; 'actual' enrolment is what was achieved. 'Active, not recruiting' means participants are still being followed but no new ones are being enrolled. 'Completed' means follow-up has finished. A separate field records whether results have been posted, and for every retatrutide trial listed above that field was false on the date checked.
- As of 14 October 2026 none of the phase 3 trials has posted registry results on ClinicalTrials.gov; efficacy and safety outcomes for TRIUMPH-1 and TRIUMPH-2 are in peer-reviewed publications, and the other trials have not yet published full results. [12][13]
- Registry entries are maintained by the sponsor and can be updated at any time, so figures here should be re-checked against the live records.
- All published retatrutide trials to date were sponsored by the manufacturer.
- Retatrutide is not approved for any indication. Regulatory status can change, and any statement about it should be dated.
Frequently Asked Questions
Is retatrutide approved?
No. Retatrutide is an investigational compound and is not approved by any regulator for any indication as of September 2026.
How many phase 3 retatrutide trials are there?
At least seven trials are registered on ClinicalTrials.gov under the TRIUMPH programme, including TRIUMPH-1 to TRIUMPH-6 and a cardiovascular and kidney outcomes trial. Four are recorded as completed and none had posted results when checked on September 18, 2026.
Have phase 3 retatrutide results been published?
Partly. TRIUMPH-1 (New England Journal of Medicine, 29 September 2026) and TRIUMPH-2 (The Lancet, online 29 September 2026) have been published. TRIUMPH-3 topline results were announced by the sponsor in July 2026, and other phase 3 trials are ongoing. [12][13] A design and rationale paper describing how the programme was planned was published in 2025, but it reports no outcomes.
What weight change did the phase 2 obesity trial report?
At 48 weeks, average weight change was −8.7%, −17.1%, −22.8% and −24.2% across the four dose groups, against −2.1% on placebo, in 338 participants. The trial's pre-specified primary endpoint was measured at 24 weeks.
