Retatrutide is an investigational compound being developed by Eli Lilly. It acts at three receptors: glucose-dependent insulinotropic polypeptide (GIP), glucagon-like peptide-1 (GLP-1) and glucagon. Lilly’s retatrutide overview describes this mechanism and its clinical development.
What the 40-week trial studied
TRANSCEND-T2D-1, published in The Lancet in 2026, was a 40-week Phase 3 trial involving adults with type 2 diabetes inadequately controlled by diet and exercise alone. Participants were randomly assigned to retatrutide or placebo in a double-blind study.
The main outcome was the change in HbA1c, a measure of blood glucose control, over 40 weeks. Change in body weight was a secondary outcome. The original TRANSCEND-T2D-1 publication reports the study methods, outcomes, adverse events and funding.
How to interpret the evidence
When reading a clinical study, consider who participated, what was compared, how long follow-up lasted and which outcomes were measured. Those details define the questions the research can answer.
The findings concern the intervention and participants studied. They do not verify the identity, purity, formulation or suitability of separately supplied products bearing the same molecule name. A commercial label or analytical certificate cannot establish that a product is equivalent to the material used in a clinical trial.
Research status
As checked on 5 November 2026, Lilly describes retatrutide as investigational and states that it has not received regulatory approval. Clinical publications should be read alongside current development information, with attention to the distinction between an experimental compound and an approved medicine.