Peptide Graded

Retatrutide

Does Retatrutide work?

Partly: some human trials, with gaps: a 338-adult trial, with larger trials not yet fully published.

BSome human evidenceIn clinical trialsas of 2026-10-26

There is one published randomized phase 2 trial in obesity (338 adults, 48 weeks), a 98-person liver fat substudy of that trial, and one published phase 3 trial, TRIUMPH-2, in 1,152 adults with obesity and type 2 diabetes over 80 weeks; other phase 3 results exist only as press releases. Multiple randomized trials point the same way, but the drug is not approved, most of the roughly 5,800-person TRIUMPH program is unpublished, and there is no long-term safety data, so the grade is B and not A. 2347

The phase 2 obesity trial randomized 338 adults without diabetes. They got one of four retatrutide doses or placebo for 48 weeks. Mean weight loss at 48 weeks was 8.7 percent at the lowest dose. It was 17.1 percent at the next, 22.8 percent at the next, and 24.2 percent at the highest. Placebo lost 2.1 percent. At the two higher doses, every participant lost at least 5 percent. More than 80 percent lost at least 15 percent. Weight was still falling at 48 weeks and had not leveled off. 2

A substudy of that trial had 98 participants with fatty liver disease. At 24 weeks, liver fat fell by 43 to 82 percent across the dose range, versus no change on placebo. By then, 86 percent of those on the highest dose had normal liver fat. 3

Evidence checklist

  • Randomised controlled trial Phase 2 and TRIUMPH-2 placebo-controlled
  • Human study over 100 people Phase 2: 338; TRIUMPH-2: 1,152
  • More than one research group All trials by Eli Lilly
  • Clinical outcomes, not surrogate markers Weight and liver fat, not clinical outcomes
  • Human safety data beyond case reports Trial data; no long-term safety

Read the full Retatrutide page

More on Retatrutide

Citations

  1. StatPearls: GLP-1 receptor agonists ncbi.nlm.nih.gov
  2. Jastreboff 2023, N Engl J Med: triple-hormone-receptor agonist retatrutide for obesity, phase 2 trial pubmed.ncbi.nlm.nih.gov
  3. Sanyal 2024, Nat Med: retatrutide for metabolic dysfunction-associated steatotic liver disease, phase 2a substudy pubmed.ncbi.nlm.nih.gov
  4. Lancet 2026: TRIUMPH-2, retatrutide in adults with obesity and type 2 diabetes doi.org
  5. Eli Lilly Q2 2026 earnings release (SEC filing): retatrutide filing plans sec.gov
  6. FDA: concerns with unapproved GLP-1 drugs used for weight loss fda.gov
  7. Diabetes Obes Metab 2026: rationale and design of the TRIUMPH registrational trials pubmed.ncbi.nlm.nih.gov
  8. Eli Lilly press release, July 2026: TRIUMPH-2 and TRIUMPH-3 topline results biospace.com
  9. ClinicalTrials.gov: retatrutide trial listings clinicaltrials.gov

Reference information only, not medical advice. Drawn from the Retatrutide article, fact-checked against the cited sources. No dosing anywhere on this site.