What the studies show
TRANSCEND-T2D-1, a published 40-week phase 3 trial in 537 adults with type 2 diabetes uncontrolled by diet and exercise: HbA1c fell 1.69–1.94 percentage points across doses versus 0.81 on placebo. The earlier phase 2 trial agreed.
“For the treatment regimen estimand, the mean change from baseline in HbA1c concentration was -1·69% (SE 0·11) with retatrutide 4 mg, -1·86% (0·10) with 9 mg, and -1·94% (0·08) with 12 mg, versus -0·81% (0·12) with placebo, resulting in estimated treatment differences versus placebo of -0·88% (95% CI -1·18 to -0·59) with retatrutide 4 mg, -1·04% (-1·32 to -0·76) with 9 mg, and -1·12% (-1·39 to -0·85) with 12 mg (all p<0·0001).”
Several well-run randomised trials in people, pointing the same way. You can plan around this. It still says nothing about whether the effect is worth the side effects for you.
- 1Bajaj HS, et al. Efficacy and safety of retatrutide in people with type 2 diabetes inadequately controlled with diet and exercise (TRANSCEND-T2D-1): a double-blind, randomised, phase 3 trial.Lancet, 2026;407:2402–2413537 randomised, 40 weeks. The first published phase 3 trial of retatrutide.
- 2Rosenstock J, et al. Retatrutide, a GIP, GLP-1 and glucagon receptor agonist, for people with type 2 diabetes: a randomised, double-blind, placebo and active-controlled, phase 2 trial.Lancet, 2023;402:529–544Phase 2 in type 2 diabetes; agrees with the phase 3 on glycaemic effect.
In context
Retatrutide is an investigational once-weekly peptide that activates three receptors at once: GIP, GLP-1 and glucagon. In TRIUMPH-1, a 2,339-person phase 3 trial published in September 2026, adults with obesity lost 25.0% of body weight at 80 weeks on the top dose against 3.9% on placebo; in adults who also have type 2 diabetes the figure was 18.8% (TRIUMPH-2). A separate published trial cut HbA1c by up to 1.9 percentage points. It is not approved anywhere, and no legitimate supply exists outside clinical trials.
Retatrutide is investigational. Legal status differs by country — see the regulation section or the jurisdiction pages.
Questions
Is Retatrutide proven to help with blood glucose?
What studies are behind the grade?
Is Retatrutide approved for this?
Other outcomes for Retatrutide
- ABody weight2 phase 3 + 1 phase 2 RCT published; 2 phase 3 topline
- BKnee osteoarthritis pain1 phase 3 RCT published (subgroup n=574); 1 phase 3 topline
- BObstructive sleep apnoea1 phase 3 RCT (subgroup n=243)
- AGI side effectsadverse2 phase 3 + 1 phase 2 RCT published; phase 3 topline
- BDysesthesia (skin sensation changes)adverse1 phase 3 RCT published; phase 3 topline
Written and maintained by LYO Research — how pages are written and checked. Reviewed 7 October 2026. Grades count human evidence only; see how LYO grades. Not medical advice. Correct this page →