What is the retatrutide dosing schedule in Phase 3 trials?

Per Lilly (May 21, 2026), participants started at 2 mg once weekly and stepped up every 4 weeks: 2 → 4 mg for the 4 mg arm, 2 → 4 → 6 → 9 mg for the 9 mg arm and 2 → 4 → 6 → 9 → 12 mg for the 12 mg arm. The Phase 2 obesity trial used 2 → 4 → 8 → 12 mg.

Can the weeks per step be changed?

Yes, the calculator accepts any number of weeks per step. The published trial protocol uses 4 weeks per step; other values are for modeling only.

Does the table show doses or dates first?

Each row is one week: week number, the Monday-to-Sunday dates from your start date, and the weekly dose. Step changes are highlighted, and the first date of each new step is listed separately.

Where can I see how a ladder changes modeled levels?

Open the same ladder in the Retatrutide plotter: it draws each step above the modeled amount so you can see the build-up after each increase.

Is retatrutide FDA approved?

No. As of Oct 19, 2026 retatrutide is investigational. Lilly reported Phase 3 results in 2026 and said it plans to submit to the FDA in the first quarter of 2027. It is legally available only to participants in Lilly clinical trials.

Retatrutide Titration Schedule Calculator

Short answer

Week of step k = 1 + weeks per step × (k − 1). Starting Jan 5, 2026, the 12 mg arm reaches 12 mg in week 17 (Apr 27) after 4-week steps at 2, 4, 6 and 9 mg. It shows the published Phase 3 trial ladder, not a recommendation; retatrutide is investigational. Dates as of Oct 19, 2026.

5 steps.

2 mg from week 1 (Jan 5, 2026)
4 mg from week 5 (Feb 2, 2026)
6 mg from week 9 (Mar 2, 2026)
9 mg from week 13 (Mar 30, 2026)
12 mg from week 17 (Apr 27, 2026)

Each tread is one step; width is weeks held, height is the weekly dose.

Phase 3 12 mg arm: week-by-week from Jan 5, 2026
Week	Dates	Weekly dose
1	Jan 5, 2026 – Jan 11, 2026	2 mg
2	Jan 12, 2026 – Jan 18, 2026	2 mg
3	Jan 19, 2026 – Jan 25, 2026	2 mg
4	Jan 26, 2026 – Feb 1, 2026	2 mg
5	Feb 2, 2026 – Feb 8, 2026	4 mg (step up)
6	Feb 9, 2026 – Feb 15, 2026	4 mg
7	Feb 16, 2026 – Feb 22, 2026	4 mg
8	Feb 23, 2026 – Mar 1, 2026	4 mg
9	Mar 2, 2026 – Mar 8, 2026	6 mg (step up)
10	Mar 9, 2026 – Mar 15, 2026	6 mg
11	Mar 16, 2026 – Mar 22, 2026	6 mg
12	Mar 23, 2026 – Mar 29, 2026	6 mg
13	Mar 30, 2026 – Apr 5, 2026	9 mg (step up)
14	Apr 6, 2026 – Apr 12, 2026	9 mg
15	Apr 13, 2026 – Apr 19, 2026	9 mg
16	Apr 20, 2026 – Apr 26, 2026	9 mg
17	Apr 27, 2026 – May 3, 2026	12 mg (step up)
18	May 4, 2026 – May 10, 2026	12 mg
19	May 11, 2026 – May 17, 2026	12 mg
20	May 18, 2026 – May 24, 2026	12 mg

Math, parameters and sources: model card.

Where the ladders come from

Retatrutide ladders in this calculator
Ladder	Steps (mg, weekly)	Source
Phase 3 12 mg arm	2 → 4 → 6 → 9 → 12	Eli Lilly, May 21, 2026
Phase 3 9 mg arm	2 → 4 → 6 → 9	Eli Lilly, May 21, 2026
Phase 3 4 mg arm	2 → 4	Eli Lilly, May 21, 2026
Phase 2 12 mg arm	2 → 4 → 8 → 12	Eli Lilly, hosted on ClinicalTrials.gov, Aug 29, 2022
Phase 2 8 mg arm (2 mg start)	2 → 4 → 8	Eli Lilly, hosted on ClinicalTrials.gov, Aug 29, 2022
Phase 2 8 mg arm (4 mg start)	4 → 8	Eli Lilly, hosted on ClinicalTrials.gov, Aug 29, 2022

The Phase 3 TRIUMPH trials started every arm at 2 mg and stepped up every 4 weeks (4, 6, 9, 12 mg). The earlier Phase 2 obesity trial used 2, 4, 8 and 12 mg. A common online preset, 2 → 4 → 8 → 12, is therefore the Phase 2 ladder, not the Phase 3 one.

Frequently asked questions

What is the retatrutide dosing schedule in Phase 3 trials?: Per Lilly (May 21, 2026), participants started at 2 mg once weekly and stepped up every 4 weeks: 2 → 4 mg for the 4 mg arm, 2 → 4 → 6 → 9 mg for the 9 mg arm and 2 → 4 → 6 → 9 → 12 mg for the 12 mg arm. The Phase 2 obesity trial used 2 → 4 → 8 → 12 mg.
Can the weeks per step be changed?: Yes, the calculator accepts any number of weeks per step. The published trial protocol uses 4 weeks per step; other values are for modeling only.
Does the table show doses or dates first?: Each row is one week: week number, the Monday-to-Sunday dates from your start date, and the weekly dose. Step changes are highlighted, and the first date of each new step is listed separately.
Where can I see how a ladder changes modeled levels?: Open the same ladder in the Retatrutide plotter: it draws each step above the modeled amount so you can see the build-up after each increase.
Is retatrutide FDA approved?: No. As of Oct 19, 2026 retatrutide is investigational. Lilly reported Phase 3 results in 2026 and said it plans to submit to the FDA in the first quarter of 2027. It is legally available only to participants in Lilly clinical trials.

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.
Study Protocol J1I-MC-GZBF(b) for NCT04881760 (Prot_000.pdf). Eli Lilly and Company, hosted on ClinicalTrials.gov, Aug 29, 2022. Accessed Oct 19, 2026.

Printed from GLP Ladder. To recreate this result, open https://glpladder.com/tools/retatrutide-titration/

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