Retatrutide in 2026: Where the Phase 3 Program Stands

What completed in 2026

The first spring milestone came from TRIUMPH-1. NCT05929066 is a Phase 3 trial in obesity and overweight with 2,335 participants. Its registry entry gives April 6, 2026 as the primary completion date and lists the study as completed.

Ten days later, TRIUMPH-3 reached its primary completion date. NCT05882045 enrolled 1,946 participants in a Phase 3 trial in obesity with cardiovascular disease. The registry records primary completion on April 16, followed by study completion on May 14, 2026. The distinction matters: primary completion marks collection of the primary outcome data, while study completion marks collection of the final data specified by the protocol.

TRIUMPH-2 followed in June. NCT05929079 is a Phase 3 trial in type 2 diabetes with obesity that enrolled 1,152 participants. It reached primary completion on June 16, 2026 and is listed as completed.

Completion status alone does not describe a study's findings. The separate TRANSCEND-T2D-1 program supplied the year's clearest publication milestone. NCT06354660 is a randomized, double-blind Phase 3 trial whose full results were published online on June 6, 2026. The paper appeared in The Lancet. The publication moves that study beyond a registry milestone into peer-reviewed reporting, without resolving the questions assigned to the trials that remain underway.

What is still running

The active program includes direct comparison studies. TRANSCEND-T2D-2, NCT06260722, compares retatrutide with semaglutide in an estimated 1,250 participants. It is listed as active and not recruiting, with estimated primary completion in August 2026.

TRIUMPH-5, NCT06662383, compares retatrutide with tirzepatide in an estimated 800 participants. That study is also active and not recruiting. Its estimated primary completion is November 2026. Until those studies complete and report, their registry entries establish design and status, not comparative findings.

The longest horizon belongs to the outcomes program. TRIUMPH-Outcomes, NCT06383390, is a Phase 3 cardiovascular and kidney outcomes trial with an estimated 10,000 participants. It is active and not recruiting, with estimated primary completion in February 2029. This timetable is why the 2026 milestones should be read as a major program update rather than a final accounting. Registry dates marked "estimated" can also change as a study progresses.

Regulatory position

The position is straightforward: retatrutide remains investigational and in active Phase 3 development, and it has no FDA approval. The completed and active Phase 3 registry entries establish an investigational development program, not authorization to market an approved drug. Lilly has not announced a filing that can be confirmed from a primary source, so there is no sound basis for assigning a submission date or forecasting an approval date.

Two federal records get cited in this context and neither one means what it is sometimes taken to mean. The FDA substance registry entry establishes a registered identity and a synonym set, which is a cataloguing act rather than a review. And a Federal Register notice published May 1, 2026 addressed the section 503B bulk drug substances list, proposing not to include semaglutide, tirzepatide and liraglutide. Retatrutide is simply not named in it, which tells you what the notice covered and nothing about retatrutide.

What this means for research material

Clinical development status and research-material documentation answer different questions. A Phase 3 trial is evidence about the material that trial used, made and released under its own controls. A catalogue vial is evidence about itself, and the paperwork that comes with it is what connects the two. Curo supplies RTA-GLP3 under its research use only policy.

For a catalog vial, the relevant evidence is lot-specific. The guide to verifying a certificate of analysis against a vial lot explains how to match the label and report. Curo's quality and testing standard uses exactly three methods: HPLC for chromatographic purity, LC-MS for molecular identity, and endotoxin testing for endotoxin burden. Each answers a different analytical question.

Documentation does not stop at the report. The guide to research-peptide and bacteriostatic-water storage describes how storage conditions relate to material integrity after receipt. These checks keep the commercial record tied to the lot in hand, while the clinical record stays tied to the named study material and protocol.

Cagrilintide is on a different timetable again: a US filing went in during December 2025, and its amylin receptor target sits outside the incretin class entirely. What it contributes to the combination is covered in Inside CagriSema: what cagrilintide contributes.

Common questions

Is retatrutide FDA approved in 2026?

No. It remains investigational and in active Phase 3 development. A registry listing, completed trial, journal publication, or SRS identity entry does not itself create FDA approval.

Which Phase 3 retatrutide trials completed this year?

TRIUMPH-1, TRIUMPH-2, and TRIUMPH-3 reached primary completion between April and June 2026. TRIUMPH-3 also reached study completion in May. TRANSCEND-T2D-1 reached a different kind of milestone when its full Phase 3 results were published in The Lancet in June.

Are the head-to-head studies finished?

Not according to the cited registry entries. TRANSCEND-T2D-2, the semaglutide comparison, and TRIUMPH-5, the tirzepatide comparison, are active and not recruiting. Their primary completion dates remain estimates.

Does a Phase 3 publication establish the quality of RTA-GLP3?

No. A trial publication describes the study material and protocol used in that trial. Quality questions about Curo's RTA-GLP3 should be answered with the certificate and analytical results for the specific catalog lot.