Published trial ladder

Retatrutide Phase 3 9 mg arm: published ladder and modeled levels

Updated by the GLP Ladder Editorial Team. Editorial policy.

Short answer

Retatrutide Phase 3 9 mg arm: 2/4/6/9 mg weekly, 4 weeks per step (Eli Lilly, May 21, 2026). The final 9 mg step begins in week 13. With t½ 6 days and R = 1.8033, the modeled amount peaks at 14.75 mg-eq. As published, not a recommendation; as of Oct 19, 2026.

Weeks per step
4 4 steps
Final step
9 mg from week 13
Modeled peak
14.75 mg-eq
Accumulation R
1.8033 t½ 6 d
Retatrutide Phase 3 9 mg arm: steps and modeled amountWeekly doses 2 mg, 4 mg, 6 mg, 9 mg; modeled amount peaks at 14.75 mg-equivalents.stable window05101520mg-eq0481216202428weeks from start2 mg4 mg6 mg9 mg
  • Weekly dose (published steps)
  • Modeled amount (mg-eq)
  • Stable window
Steps start on a Monday (Jan 5, 2026) for illustration. Curve: modeled relative amount, not plasma concentration. Open in the Retatrutide plotter to change dates or doses.
Phase 3 9 mg arm: weeks, weekly dose and dates from a Jan 5, 2026 start (Eli Lilly, May 21, 2026)
WeeksWeekly doseFirst week starts
1–4 2 mg Jan 5, 2026
5–8 4 mg Feb 2, 2026
9–12 6 mg Mar 2, 2026
13 onward 9 mg Mar 30, 2026

Weekly modeled amounts

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28 weeks. Highlighted rows start a new dose step. Model details: model card.

Retatrutide Phase 3 9 mg arm: weekly peak, trough and average (mg-equivalents)
WeekStartsDose mgPeakTroughAverage
1Jan 5, 202621.78201.287
2Jan 12, 202622.6080.9211.945
3Jan 19, 202622.9781.3312.238
4Jan 26, 202623.1441.5142.368
5Feb 2, 202644.9931.5953.713
6Feb 9, 202645.8572.5534.397
7Feb 16, 202646.2442.9794.701
8Feb 23, 202646.4173.1694.837
9Mar 2, 202668.2663.2546.184
10Mar 9, 202669.1344.2126.869
11Mar 16, 202669.5214.6397.174
12Mar 23, 202669.6944.8297.31
13Mar 30, 2026912.434.9149.3
14Apr 6, 2026913.7146.33310.314
15Apr 13, 2026914.2886.96610.766
16Apr 20, 2026914.5447.24710.967
17Apr 27, 2026914.6587.37311.057
18May 4, 2026914.7097.42911.097
19May 11, 2026914.7317.45311.114
20May 18, 2026914.7417.46511.122
21May 25, 2026914.7467.46911.126
22Jun 1, 2026914.7487.47211.127
23Jun 8, 2026914.7497.47311.128
24Jun 15, 2026914.7497.47311.128
25Jun 22, 2026—7.7673.4765.339
26Jun 29, 2026—3.461.5492.378
27Jul 6, 2026—1.5410.691.059
28Jul 13, 2026—0.6860.3070.472

Sources

  1. Lilly's triple agonist, retatrutide, delivered powerful weight loss in pivotal Phase 3 obesity trial. Eli Lilly and Company (via PR Newswire; also investor.lilly.com), May 21, 2026. Accessed Oct 19, 2026.
  2. Retatrutide, a Triple Hormone Receptor Agonist, for Treatment of Obesity. N Engl J Med (abstract via PubMed PMID 42814954; doi:10.1056/NEJMoa2604169), Sep 29, 2026. Accessed Oct 19, 2026.
  3. A Study of Retatrutide (LY3437943) in Participants Who Have Obesity or Overweight (TRIUMPH-1). ClinicalTrials.gov (U.S. NLM), Aug 21, 2026. Accessed Oct 19, 2026.
  4. LY3437943, 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. The Lancet 2022;400(10366):1869-1881 (abstract via PubMed PMID 36354040; doi:10.1016/S0140-6736(22)02033-5), Oct 27, 2022. Accessed Oct 19, 2026.

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