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Retatrutide

Retatrutide is an experimental drug from Eli Lilly that activates three hormone receptors: GIP, GLP-1 and glucagon. It is injected under the skin and is in late-stage (phase 3) trials for obesity, type 2 diabetes and related conditions. It is not approved anywhere, so anything sold outside a clinical trial is not a regulated medicine.

In clinical trialsWADA Not named; as an unapproved drug it falls under S0 (prohibited at all times)Checked October 2026
Open the Retatrutide calculatorSources

Approval status

Not approved anywhere. Phase 3 trials (the TRIUMPH and TRANSCEND programs) reported results in 2025 and 2026, and in July 2026 Lilly said it plans to submit it to the FDA in early 2027. FDA has warned companies selling retatrutide falsely labeled "for research purposes" or "not for human consumption".45611

What it’s used or studied for

  • Human studies

    Weight loss in adults with obesity without diabetes: phase 2 and phase 3 (TRIUMPH-1) trials found much larger weight reductions than placebo.78

  • Human studies

    Blood sugar control and weight loss in adults with type 2 diabetes, with or without obesity (TRANSCEND-T2D-1 and TRIUMPH-2 trials).910

  • Human studies

    Less knee pain in people with obesity and knee osteoarthritis (TRIUMPH-4 and a TRIUMPH-1 substudy).711

  • Human studies

    Fewer breathing pauses during sleep in adults with obesity or overweight and moderate to severe obstructive sleep apnea (TRIUMPH-1 and TRIUMPH-2 substudies).12

  • Human studies

    Large drops in liver fat in people with obesity and fatty liver disease (MASLD) in a phase 2 substudy.13

  • Human studies

    Weight loss in adults with severe obesity and heart disease (TRIUMPH-3); this trial did not show a clear effect on heart attacks or strokes.4

Each label shows how strong the evidence is: an approved use, human studies, animal or lab studies only, or a popular claim with no published studies. Being studied is not the same as being proven safe or effective.

Side effects

Common

  • Nausea
  • Diarrhea
  • Vomiting
  • Constipation
  • Dysesthesia (unusual or uncomfortable skin sensations)
  • Faster heart rate, peaking around 6 months and then easing
  • Low blood pressure (less common)

There is no approved label; these come from trials. Stomach and bowel effects were the most common and rose with dose. In TRIUMPH-4, 18% of people on the highest dose stopped because of side effects, versus 4% on placebo.8911

Cautions

  • FDA has warned companies selling retatrutide labeled "for research purposes" and urges people not to buy these products.5
  • A 2026 case report describes a hospital stay for severe, persistent vomiting after injections of an unverified product said to contain retatrutide.14
  • FDA states that retatrutide cannot be used in compounding under federal law.5

Sources

  1. KEGG DRUG: Retatrutide (D12430)
  2. FDA Global Substance Registration System (GSRS): Retatrutide
  3. Coskun T et al. LY3437943, a novel triple glucagon, GIP, and GLP-1 receptor agonist for glycemic control and weight loss (Cell Metab, 2022)
  4. Eli Lilly press release: Retatrutide successful in two additional Phase 3 obesity trials (TRIUMPH-2, TRIUMPH-3), 23 July 2026
  5. FDA: FDA's concerns with unapproved GLP-1 drugs used for weight loss
  6. WADA 2026 Prohibited List
  7. Jastreboff AM et al. Retatrutide, a triple hormone receptor agonist, for treatment of obesity (TRIUMPH-1) (N Engl J Med, 2026)
  8. Jastreboff AM et al. Triple-hormone-receptor agonist retatrutide for obesity: a phase 2 trial (N Engl J Med, 2023)
  9. Bellido V et al. Retatrutide in adults with obesity and type 2 diabetes (TRIUMPH-2) (Lancet, 2026)
  10. Bajaj HS et al. Retatrutide in people with type 2 diabetes inadequately controlled with diet and exercise (TRANSCEND-T2D-1) (Lancet, 2026)
  11. Eli Lilly press release: Retatrutide TRIUMPH-4 results in obesity and knee osteoarthritis, 11 December 2025
  12. Grunstein RR et al. Retatrutide once weekly for treatment of obstructive sleep apnea (N Engl J Med, 2026)
  13. Sanyal AJ et al. Retatrutide for metabolic dysfunction-associated steatotic liver disease: a randomized phase 2a trial (Nat Med, 2024)
  14. Buzzi RM, Huber LC. Refractory nausea associated with peptide injections reported to contain retatrutide (BMJ Case Rep, 2026)

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