Published trial ladder
Retatrutide Phase 3 4 mg arm: published ladder and modeled levels
Short answer
Retatrutide Phase 3 4 mg arm: 2/4 mg weekly, 4 weeks per step (Eli Lilly, May 21, 2026). The final 4 mg step begins in week 5. With t½ 6 days and R = 1.8033, the modeled amount peaks at 6.56 mg-eq. As published, not a recommendation; as of Oct 19, 2026.
- Weeks per step
- 4 2 steps
- Final step
- 4 mg from week 5
- Modeled peak
- 6.56 mg-eq
- Accumulation R
- 1.8033 t½ 6 d
- Weekly dose (published steps)
- Modeled amount (mg-eq)
- Stable window
| Weeks | Weekly dose | First week starts |
|---|---|---|
| 1–4 | 2 mg | Jan 5, 2026 |
| 5 onward | 4 mg | Feb 2, 2026 |
Weekly modeled amounts
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24 weeks. Highlighted rows start a new dose step. Model details: model card.
| Week | Starts | Dose mg | Peak | Trough | Average |
|---|---|---|---|---|---|
| 1 | Jan 5, 2026 | 2 | 1.782 | 0 | 1.287 |
| 2 | Jan 12, 2026 | 2 | 2.608 | 0.921 | 1.945 |
| 3 | Jan 19, 2026 | 2 | 2.978 | 1.331 | 2.238 |
| 4 | Jan 26, 2026 | 2 | 3.144 | 1.514 | 2.368 |
| 5 | Feb 2, 2026 | 4 | 4.993 | 1.595 | 3.713 |
| 6 | Feb 9, 2026 | 4 | 5.857 | 2.553 | 4.397 |
| 7 | Feb 16, 2026 | 4 | 6.244 | 2.979 | 4.701 |
| 8 | Feb 23, 2026 | 4 | 6.417 | 3.169 | 4.837 |
| 9 | Mar 2, 2026 | 4 | 6.494 | 3.254 | 4.898 |
| 10 | Mar 9, 2026 | 4 | 6.528 | 3.291 | 4.924 |
| 11 | Mar 16, 2026 | 4 | 6.543 | 3.308 | 4.936 |
| 12 | Mar 23, 2026 | 4 | 6.55 | 3.316 | 4.942 |
| 13 | Mar 30, 2026 | 4 | 6.553 | 3.319 | 4.944 |
| 14 | Apr 6, 2026 | 4 | 6.554 | 3.32 | 4.945 |
| 15 | Apr 13, 2026 | 4 | 6.555 | 3.321 | 4.946 |
| 16 | Apr 20, 2026 | 4 | 6.555 | 3.321 | 4.946 |
| 17 | Apr 27, 2026 | 4 | 6.555 | 3.321 | 4.946 |
| 18 | May 4, 2026 | 4 | 6.555 | 3.321 | 4.946 |
| 19 | May 11, 2026 | 4 | 6.555 | 3.322 | 4.946 |
| 20 | May 18, 2026 | 4 | 6.555 | 3.322 | 4.946 |
| 21 | May 25, 2026 | — | 3.452 | 1.545 | 2.373 |
| 22 | Jun 1, 2026 | — | 1.538 | 0.688 | 1.057 |
| 23 | Jun 8, 2026 | — | 0.685 | 0.307 | 0.471 |
| 24 | Jun 15, 2026 | — | 0.305 | 0.137 | 0.21 |
Sources
- 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.
- 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.
- 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.
- 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.