Retatrutide (LY3437943) is an investigational peptide from Eli Lilly that activates three receptors: GIP, GLP-1 and glucagon. It is one of the most closely followed compounds in metabolic research. This update covers where its clinical development stands as of September 2026. For background on how it works, see What Is Retatrutide? and Semaglutide vs Tirzepatide vs Retatrutide.
From Phase 2 to Phase 3
Phase 2 results for retatrutide were published in 2023, in studies of adults with obesity and of adults with type 2 diabetes. These results led Lilly to start TRIUMPH, a Phase 3 programme of several large trials in different populations, alongside other late-stage studies.
Trials that have reported
- TRIUMPH-4 (December 2025): the first Phase 3 readout. It studied adults with obesity or overweight and knee osteoarthritis over 68 weeks, and Lilly reported that it met its primary endpoints.
- TRIUMPH-1 (May 2026): the main obesity trial, with 2,339 adults with obesity or overweight and at least one related condition (without diabetes), over 80 weeks. Lilly reported that all study arms met the primary and key secondary endpoints, with an extension period running to 104 weeks.
Full data from these trials are being presented at scientific meetings and in peer-reviewed publications, which are the best place to read the detailed findings, including safety and tolerability data.
What is still to come
- TRIUMPH-2 is studying adults with obesity or overweight and type 2 diabetes.
- TRIUMPH-3 is studying adults with obesity or overweight and established cardiovascular disease.
- Further late-stage readouts are expected by the end of 2026.
Regulatory status
Retatrutide is not approved by Health Canada, the FDA or any other regulator. It remains investigational, and commentators do not expect an approval decision before 2027 at the earliest.
Why it matters for research
As the first triple agonist to reach Phase 3, retatrutide gives researchers a way to study how glucagon receptor activity combines with incretin signalling. Comparing it with single (semaglutide) and dual (tirzepatide) agonists helps separate the role of each pathway in metabolic models.
Research material
ReVICO supplies Retatrutide (10mg) and Retatrutide (20mg) as lyophilized powder for laboratory research, with independent Janoshik reports on each product page.
Sources
- Eli Lilly: TRIUMPH-1 topline release (May 2026)
- Eli Lilly: TRIUMPH-4 topline release (December 2025)
- Rationale and design of the TRIUMPH registrational trials (PubMed)
All ReVICO Labs products are supplied for laboratory research use only. They are not for human or veterinary consumption and are not approved by Health Canada for therapeutic or diagnostic use.
