Large Phase 3 human trials now exist. A peer-reviewed Phase 3 diabetes trial showed substantial improvements in blood sugar and body weight, while several obesity Phase 3 results are still available mainly as sponsor or congress reports. Retatrutide remains investigational and is not approved.
Still uncertain: Long-term heart and other major health outcomes, the final Phase 3 benefit-risk picture, an approved regimen, and whether non-trial products are equivalent in identity or purity.
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STUDY DATA VISUAL
Phase 3 study snapshot: mean body-weight change
TRANSCEND-T2D-1 · adults with type 2 diabetes · N=537 · 40 weeks · treatment-regimen estimand · mean percentage body-weight change from baseline
This chart describes one Phase 3 diabetes trial. It does not establish an approved obesity indication or long-term cardiovascular benefit. Bars use a common 0–25% weight-change scale across these WhichPeps charts. Separate trials are not head-to-head comparisons; populations, estimands and designs can differ.
View chart values as text
Phase 3 study snapshot: mean body-weight change table
Group
Mean body-weight change
Placebo
−2.6%
4 mg
−11.5%
9 mg
−13.9%
12 mg
−15.3%
Phase 3 study snapshot: mean body-weight change table
Peer-reviewed Phase 3 TRANSCEND-T2D-1 demonstrated glycaemic and body-weight efficacy in adults with type 2 diabetes. Positive TRIUMPH Phase 3 obesity results have also been reported, although several remain sponsor/congress reports rather than full peer-reviewed publications.
Regulatory status
Not approved by any regulatory agency. Lilly reported in July 2026 that it plans a U.S. Biologics License Application submission in Q1 2027.
Main limitations
Retatrutide is not yet approved; source maturity differs across Phase 3 results, and long-term cardiovascular, renal and rare-event safety outcomes remain incomplete.
Safety
Gastrointestinal adverse effects and dose-related tolerability issues remain important; heart-rate increases have been observed. Longer-term and rare-event safety continue to be studied.
Evidence reviewed
2026-09-20
i
Retatrutide now has multiple positive Phase 3 trials across obesity and type 2 diabetes. TRANSCEND-T2D-1 is peer reviewed; several TRIUMPH results remain sponsor/congress topline data. It remains investigational.
Outcome-level evidence
Evidence is not one score.
Each record below answers a narrower question about an outcome, population or context. Evidence status and the study finding are shown separately so strong evidence is not mistaken for a positive effect.
Glycaemic control and body weight in type 2 diabetes
Human evidence
Randomized Phase 3 human evidence
Context: Adults with type 2 diabetes inadequately controlled with diet and exercise alone
Finding: TRANSCEND-T2D-1 (n=537) reported substantial HbA1c reductions and mean body-weight changes of -11.5% to -15.3% across retatrutide groups versus -2.6% with placebo at 40 weeks.
Regulatory / scope context: This trial does not establish long-term cardiovascular outcomes or an approved retatrutide product/regimen.
Mean HbA1c change was -1.69%, -1.86% and -1.94% with retatrutide 4/9/12 mg versus -0.81% with placebo; mean body-weight change was -11.5%, -13.9% and -15.3% versus -2.6%.
Lilly reported positive weight and glycaemic outcomes and stated that it plans a U.S. BLA submission in Q1 2027. Full peer-reviewed reports remain relevant.
Gastrointestinal adverse effects and dose-related tolerability issues remain important; heart-rate increases have been observed. Longer-term and rare-event safety continue to be studied.
GI symptoms, dose-related tolerability issues, heart-rate increase; long-term risk profile remains under study.
Technical details
Mechanism / biologyActivates GIP, GLP-1 and glucagon receptors, affecting appetite, glycaemia and energy balance.
Route / formulation boundaryEvidence applies to trial-grade retatrutide, not to unverified research-market vials or pens.
Identity / data-quality noteUse the canonical compound identity and studied formulation when interpreting evidence.
Study / label regimen evidenceVerified study/label regimen evidence is available. Published Phase 2 human trial regimen. Open descriptive regimen evidence →
WhichPeps does not rely on a single headline study when the evidence base is broader. Primary research, registries, regulators and supporting records are kept distinct.
3structured study records
2outcome records
8linked source records
How to read these counts: they show evidence coverage, not evidence strength. One large, well-designed study can be more informative than several weak or indirect records.
Show supporting and discovery sources
Study pages above contain the records used for public evidence summaries. The links below include supporting, regulatory and literature-discovery sources; a registry or search result is not treated as proof of benefit.
Evidence rule: WhichPeps keeps human, animal, laboratory, regulatory and product/formulation evidence distinct. Common names help people find the page; they do not change the underlying scientific identity.
