Retatrutide for Diabetes: What the Evidence Shows
What human and animal studies show about Retatrutide for diabetes, how strong that evidence is, and what is still unproven.
- Strongest evidence
- Human RCT
- Human studies
- 53
- PubMed records, our ledger
- Animal studies
- 6
- PubMed records, our ledger
- Studies we summarised
- 5
- with an outcome for diabetes
Evidence for diabetes
Each row is an outcome related to diabetes from a published study, strongest design first. Animal and cell results are labelled and are not human results. User reports are not counted as evidence here.
| Outcome | Result | Study type | Source |
|---|---|---|---|
| Body weight at week 80 (primary) | At week 80 body weight changed by -18·8% with 12 mg, -16·8% with 9 mg and -11·9% with 4 mg, versus -5·1% with placebo. | Human RCTn = 1152 | Lancet 2026, PMID 42810372 |
| Glycaemic control | Retatrutide was associated with improved glycaemic control in obesity with type 2 diabetes (no HbA1c figure in the abstract). | Human RCTn = 1152 | Lancet 2026, PMID 42810372 |
| HbA1c at week 40 (primary) | HbA1c changed by -1·94% with 12 mg, -1·86% with 9 mg and -1·69% with 4 mg, versus -0·81% with placebo. | Human RCTn = 537 | Lancet 2026, PMID 42250575 |
| Body weight at week 40 | Body weight changed by -15·3% with 12 mg, -13·9% with 9 mg and -11·5% with 4 mg, versus -2·6% with placebo. | Human RCTn = 537 | Lancet 2026, PMID 42250575 |
| HbA1c at 24 weeks (primary) | HbA1c changed by -2·02% with 12 mg escalation, versus -0·01% with placebo and -1·41% with 1·5 mg dulaglutide. | Human RCTn = 281 | Lancet 2023, PMID 37385280 |
| Body weight at 36 weeks | At 36 weeks body weight fell by 16·94% with 12 mg escalation, versus 3·00% with placebo and 2·02% with 1·5 mg dulaglutide. | Human RCTn = 281 | Lancet 2023, PMID 37385280 |
| HbA1c (placebo-adjusted) | Placebo-adjusted HbA1c fell by -1·4% (3 mg), -1·6% (3/6 mg) and -1·2% (3/6/9/12 mg) in the three highest dose groups. | Human RCTn = 72 | Lancet 2022, PMID 36354040 |
| Body weight and glycaemic control in obese mice | In obese mice, LY3437943 (retatrutide) decreased body weight and improved glycaemic control. | Animal · mouse (plus a human phase 1 single-ascending-dose study reported in the same paper) (not a human result) | Cell metabolism 2022, PMID 35985340 |
PubMed records for Retatrutide and diabetes: 53 human, 6 animal (search counts, not studies we reviewed). Grades follow our .
How strong is it?
A human randomized trial outweighs any number of animal studies. Animal and cell results show a mechanism worth testing, not that it works in people.
Type 2 diabetes and the retatrutide trials built around it
MedlinePlus calls type 2 diabetes the most common form, one in which the body may still make insulin but its cells respond poorly to it.[9]
The phase 2 diabetes trial enrolled adults aged 18 to 75 with type 2 diabetes and an HbA1c of 7.0 to 10.5%.[6]
In its registry entry, one 12 mg arm of that phase 2 trial is described as a 2 mg starting dose followed by 4 mg, then 8 mg, then 12 mg, all by weekly subcutaneous injection.[10]
What happened to blood sugar in the studies
In the phase 2 diabetes trial, the 12 mg escalation group's HbA1c fell by 2.02% from baseline at 24 weeks, against 0.01% on placebo and 1.41% on 1.5 mg dulaglutide.[6]
As a monotherapy in adults whose type 2 diabetes was inadequately controlled by diet and exercise, the 12 mg group's HbA1c fell 1.94% against 0.81% on placebo.[5]
An early 12-week phase 1b trial under the name LY3437943 found placebo-adjusted mean daily plasma glucose lower by 2.8, 3.1 and 2.9 mmol/L in its three highest dose groups.[7]
In obese mice, LY3437943 lowered body weight and improved glycemic control; this is animal data.[8]
Safety in the diabetes populations
In the monotherapy diabetes trial, 2-5% of retatrutide recipients stopped because of adverse events (0% on placebo), and no severe hypoglycaemia was reported.[5]
In TRIUMPH-2, the adults with obesity and type 2 diabetes who stopped for adverse events or death numbered 12% on 9 mg and 8% on 12 mg, versus 4% on 4 mg and 5% on placebo.[4]
The phase 2 diabetes trial reported no severe hypoglycaemia and no deaths.[6]
How much diabetes research exists
A PubMed search of retatrutide with diabetes terms (2026-10-02) found 53 human-only papers and 6 under the animal filter; 6 carried a randomized-trial tag.
Calculated from pubmed query (retatrutide[tiab] OR LY3437943[tiab]) AND (diabet*[tiab] OR "insulin resistance"[tiab] OR "insulin sensitivity"[tiab] OR glycemic[tiab] OR glycaemic[tiab] OR HbA1c[tiab] OR hyperglyc*[tiab] OR "glucose tolerance"[tiab]); date 2026-10-02; human only count 53; animal filter count 6; randomized filter count 6. Formula: counts as recorded in the goals.json ledger (PubMed [tiab] query with the human-only, animal and RCT filters shown)
Other peptides people research for diabetes
All peptides for diabetes, comparedCommon questions
Does Retatrutide help with diabetes?
The strongest study we summarise for diabetes is human rct evidence, across 5 studies with an outcome for diabetes. A trial result is not an approval; see the legal status.
Is Retatrutide approved for diabetes?
No. Retatrutide is not FDA approved for any use, including diabetes.
What is the best peptide for diabetes?
There is no single answer. Our diabetes overview compares each candidate by evidence grade and legal status rather than by popularity.
Does retatrutide lower blood sugar?
In people with type 2 diabetes, the trial authors report glycaemic improvements with retatrutide, and the phase 2 trial compared HbA1c changes with placebo and dulaglutide.[5]
Is there a retatrutide trial in type 1 diabetes?
The trial abstracts cached for this page describe adults with type 2 diabetes; none of them reports a retatrutide study in type 1 diabetes.[6]
What was the main outcome of the phase 2 retatrutide diabetes trial?
The registry describes the phase 2 diabetes trial's primary outcome as the HbA1c change from baseline in the retatrutide groups relative to placebo.[10]
More on Retatrutide
Sources
- 1Triple-Hormone-Receptor Agonist Retatrutide for Obesity: A Phase 2 Trial (Jastreboff AM et al.)New England Journal of Medicine · 2023PMID 37366315Accessed 2 Oct 2026
- 2Retatrutide, a Triple Hormone Receptor Agonist, for Treatment of Obesity (TRIUMPH-1; Jastreboff AM et al.)New England Journal of Medicine · 2026PMID 42814954Accessed 2 Oct 2026
- 3A Phase 2 Study of Once-Weekly LY3437943 Compared With Placebo in Participants Who Have Obesity or Are Overweight With Weight-Related Comorbidities (NCT04881760; arms and posted results)ClinicalTrials.gov (U.S. National Library of Medicine) · 2021clinicaltrials.govAccessed 2 Oct 2026
- 4Retatrutide in adults with obesity and type 2 diabetes (TRIUMPH-2): a double-blind, parallel-group, randomised, placebo-controlled, phase 3 trial.Lancet (London, England) · 2026PMID 42810372Accessed 2 Oct 2026
- 5Efficacy and safety of retatrutide, a GIP, GLP-1, and glucagon receptor agonist, in people with type 2 diabetes and inadequate glycaemic control with diet and exercise (TRANSCEND-T2D-1): a double-blind, randomised, phase 3 trial.Lancet (London, England) · 2026PMID 42250575Accessed 2 Oct 2026
- 6Retatrutide, a GIP, GLP-1 and glucagon receptor agonist, for people with type 2 diabetes: a randomised, double-blind, placebo and active-controlled, parallel-group, phase 2 trial conducted in the USA.Lancet (London, England) · 2023PMID 37385280Accessed 2 Oct 2026
- 7LY3437943, a novel triple GIP, GLP-1, and glucagon receptor agonist in people with type 2 diabetes: a phase 1b, multicentre, double-blind, placebo-controlled, randomised, multiple-ascending dose trial.Lancet (London, England) · 2022PMID 36354040Accessed 2 Oct 2026
- 8LY3437943, a novel triple glucagon, GIP, and GLP-1 receptor agonist for glycemic control and weight loss: From discovery to clinical proof of concept.Cell metabolism · 2022PMID 35985340Accessed 2 Oct 2026
- 9Official web pageOfficial web page · web page
- 10A Phase 2 Study of Once-Weekly LY3437943 Compared With Placebo and Dulaglutide in Participants With Type 2 DiabetesClinicalTrials.gov (U.S. National Library of Medicine) · 2021clinicaltrials.govAccessed 2 Oct 2026
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