Retatrutide
Also called LY3437943
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In 30 seconds
An experimental peptide that switches on three hormone receptors: GIP, GLP-1 and glucagon.[5]
Phase 3 trials are published, including TRIUMPH-1 with 2,339 adults.[6]
How far has the research gotten?
People in its biggest studies
How many people each study enrolled, as reported.Research over time
Papers on PubMed each year that mention Retatrutide.59 papers in 2025DailyMed lists retatrutide pens from another company as "Export only", with no FDA approval number.[2]
What studies used
What each paper reports. A record of published research, not a recommendation.The TRIUMPH-1 phase 3 trial compared retatrutide with placebo for body-weight change in 2339 adults with obesity without diabetes, with subgroups assessing knee osteoarthritis pain and obstructive sleep apnea.
N Engl J Med · 2026 · PubMed 42814954What the paper reports
4 mg, 9 mg or 12 mg once weekly subcutaneously for 80 weeks
Who: humanThe TRIUMPH-2 phase 3 trial compared retatrutide with placebo for body-weight change in 1152 adults with obesity or overweight and type 2 diabetes.
Lancet · 2026 · PubMed 42810372What the paper reports
4 mg, 9 mg or 12 mg once weekly by subcutaneous injection, with the primary endpoint at week 80
Who: humanThe TRANSCEND-T2D-1 phase 3 trial compared retatrutide alone with placebo for change in HbA1c in 537 adults with type 2 diabetes not controlled by diet and exercise.
Lancet · 2026 · PubMed 42250575What the paper reports
4 mg, 9 mg or 12 mg once weekly by subcutaneous injection for 40 weeks
Who: humanThis phase 2 trial compared several retatrutide doses with placebo for body-weight change in 338 adults with obesity or overweight.
N Engl J Med · 2023 · PubMed 37366315What the paper reports
1 mg, 4 mg (starting at 2 mg or 4 mg), 8 mg (starting at 2 mg or 4 mg) or 12 mg (starting at 2 mg) subcutaneously once weekly for 48 weeks
Who: humanWhat it is, in full 4
Retatrutide is an experimental single peptide that switches on three hormone receptors at once: the GIP, GLP-1 and glucagon receptors[5].
Eli Lilly is developing it and sponsors its trials, where it appears under the code name LY3437943[10][11].
Lilly scientists published its discovery and first single-dose human results in 2022, reporting weight loss in obese mice and a blood-level profile in people compatible with once-weekly dosing[4].
No FDA-approved retatrutide product was found in Drugs@FDA, and its most advanced registered trials are phase 3[1][9].
Regulatory details 3
No retatrutide application was found in Drugs@FDA via openFDA; DailyMed does list several retatrutide products from a labeler other than the trial sponsor (Guangzhou Yixin Cross-Border E-Commerce Co., Ltd.) (for example 'SALKALLI') under the marketing category 'Export only', with no NDA or BLA number (source[2]).[1]
Checked 2026-10-06Retatrutide does not appear in Category 1, 2 or 3 of FDA's list of bulk drug substances nominated for 503A compounding (version updated May 14, 2026).[3]
Checked 2026-10-06Retatrutide is not named on the 2026 Prohibited List or Monitoring Program; the List's S0 section bans any substance not covered elsewhere that lacks current government approval for human therapeutic use (including drugs in clinical development), but the List does not say whether retatrutide falls under it (Monitoring Program checked at source[13]).[12]
Checked 2026-10-06Human trials on ClinicalTrials.gov
An intervention search for retatrutide on ClinicalTrials.gov returned 33 registered records (including one expanded-access listing), the most advanced being phase 3 (14 studies tagged phase 3, among them the TRIUMPH program)[9].
All sources 13
- Drugs@FDA (openFDA) search by active ingredient: retatrutide (no matches)U.S. FDA (openFDA)
- SALKALLI (retatrutide pen 30 mg) listing, marketing category 'Export only'DailyMed (U.S. National Library of Medicine)
- Bulk Drug Substances Nominated for Use in Compounding Under Section 503A (updated May 14, 2026)U.S. FDA
- Coskun T et al. LY3437943, a novel triple glucagon, GIP, and GLP-1 receptor agonist for glycemic control and weight loss: From discovery to clinical proof of concept. Cell Metab 2022PubMed
- Jastreboff AM et al. Triple-Hormone-Receptor Agonist Retatrutide for Obesity - A Phase 2 Trial. N Engl J Med 2023PubMed
- Jastreboff AM et al. Retatrutide, a Triple Hormone Receptor Agonist, for Treatment of Obesity. N Engl J Med 2026 (TRIUMPH-1)PubMed
- Bellido V et al. Retatrutide in adults with obesity and type 2 diabetes (TRIUMPH-2). Lancet 2026PubMed
- Bajaj HS et al. TRANSCEND-T2D-1. Lancet 2026PubMed
- ClinicalTrials.gov intervention search: retatrutideClinicalTrials.gov (U.S. National Library of Medicine)
- NCT05929066: A Study of Retatrutide (LY3437943) in Participants Who Have Obesity or Overweight (TRIUMPH-1)ClinicalTrials.gov (U.S. National Library of Medicine)
- NCT04881760: A Study of LY3437943 in Participants Who Have Obesity or Are Overweight (sponsor Eli Lilly and Company)ClinicalTrials.gov (U.S. National Library of Medicine)
- World Anti-Doping Code International Standard: Prohibited List 2026World Anti-Doping Agency
- The 2026 Monitoring ProgramWorld Anti-Doping Agency
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