Retatrutide has no label. It is the most-searched dosage term on this site without one, and the gap is filled online by figures that range from a quarter of a milligram to twelve. This page separates the figures with a checkable source, which are the trial protocols and Lilly's own trial releases, from the figures without one, and then converts the sourced figures into syringe units for the vial sizes the research market sells.
Retatrutide (LY3437943) is an investigational once-weekly peptide from Eli Lilly that acts at the GIP, GLP-1 and glucagon receptors. Medibact's Retatrutide guide covers the molecule and its evidence; this page stays with dosing figures. The dosage hub lists every compound.
What the sources state
| Source | Kind | Figure | Date read |
|---|---|---|---|
| DailyMed SPL search | Label search | No FDA-approved product; ten records, all "Export only" listings from one e-commerce labeler, marketing start late October 2025 | 2026-09-18 |
| Phase 2, NCT04881760 (338 participants; results posted 2023-09-13) | Trial protocol | 1, 4, 8, 12 mg once weekly for 48 weeks; escalation arms started at 2 or 4 mg | 2026-09-18 |
| Jastreboff et al., NEJM 2023 (PMID 37366315) | Trial publication | Weight change at 48 weeks: -8.7% (1 mg), -17.1% (4 mg), -22.8% (8 mg), -24.2% (12 mg), -2.1% (placebo) | 2026-09-18 |
| TRIUMPH-1, NCT05929066 (2,335 enrolled; completed 2026-04-30) | Trial protocol | Three dose groups, 80-week treatment period, 24-week extension | 2026-09-18 |
| Lilly release, 2026-05-21 (TRIUMPH-1) | Sponsor release | 4, 9, 12 mg: -19.0%, -25.9%, -28.3% at 80 weeks vs -2.2%; 12 mg -30.3% at 104 weeks (BMI ≥ 35 extension); steps of 2, 4, 6, 9 mg | 2026-09-18 |
| Lilly release, 2026-07-23 (TRIUMPH-2 and -3) | Sponsor release | Start 2 mg once weekly, increase every four weeks; T2D: -12.7%, -19.1%, -20.8% vs -4.0%; CVD: -21.6%, -22.6% vs -3.2% | 2026-09-18 |
| Forum and vendor pages | Commonly cited | 0.25 to 0.5 mg a week rising to 1.5 to 4 mg over 8 to 12 weeks; also trial-mirroring 2 to 12 mg schedules | 2026-09-18 |
The trial rows agree with one another: every escalation arm in every registered trial began at 2 mg or 4 mg, and no arm was ever below 1 mg. The last row is the only one that contradicts them, and it has no source behind it that can be opened.
The export-only listings, explained
DailyMed indexes labelling documents that companies file for many kinds of product, including drugs made for export that are not marketed in the United States. On 2026-09-18 all ten retatrutide records came from one labeler, Guangzhou Yixin Cross-border E-commerce Co., Ltd., under the marketing category "Export only", with marketing start dates of 29 and 30 October 2025. Each carries its own dosing table, running from 2.5 mg a week to 10 mg a week. Those tables are the labeler's own text; no regulator reviewed them, and they should not be read as a label in the sense the Zepbound or Wegovy documents are. They are reported here so that a reader who finds them on DailyMed knows what they are.
Units per dose at each research-vial size
Research-market retatrutide is supplied in 5 mg, 10 mg and 20 mg vials. The table takes each at 1, 2 and 3 mL of water, gives the resulting concentration, and converts the trial figures into U-100 syringe units (100 units = 1 mL). A cell over 100 units does not fit one syringe at that concentration.
| Vial | Water added | Concentration | 1 mg | 2 mg | 4 mg | 6 mg | 8 mg | 9 mg | 12 mg |
|---|---|---|---|---|---|---|---|---|---|
| 5 mg | 1 mL | 5 mg/mL | 20 | 40 | 80 | 120 (>1 syringe) | 160 (>1 syringe) | 180 (>1 syringe) | 240 (>1 syringe) |
| 5 mg | 2 mL | 2.5 mg/mL | 40 | 80 | 160 (>1 syringe) | 240 (>1 syringe) | 320 (>1 syringe) | 360 (>1 syringe) | 480 (>1 syringe) |
| 5 mg | 3 mL | 1.67 mg/mL | 60 | 120 (>1 syringe) | 240 (>1 syringe) | 360 (>1 syringe) | 480 (>1 syringe) | 540 (>1 syringe) | 720 (>1 syringe) |
| 10 mg | 1 mL | 10 mg/mL | 10 | 20 | 40 | 60 | 80 | 90 | 120 (>1 syringe) |
| 10 mg | 2 mL | 5 mg/mL | 20 | 40 | 80 | 120 (>1 syringe) | 160 (>1 syringe) | 180 (>1 syringe) | 240 (>1 syringe) |
| 10 mg | 3 mL | 3.33 mg/mL | 30 | 60 | 120 (>1 syringe) | 180 (>1 syringe) | 240 (>1 syringe) | 270 (>1 syringe) | 360 (>1 syringe) |
| 20 mg | 1 mL | 20 mg/mL | 5 | 10 | 20 | 30 | 40 | 45 | 60 |
| 20 mg | 2 mL | 10 mg/mL | 10 | 20 | 40 | 60 | 80 | 90 | 120 (>1 syringe) |
| 20 mg | 3 mL | 6.67 mg/mL | 15 | 30 | 60 | 90 | 120 (>1 syringe) | 135 (>1 syringe) | 180 (>1 syringe) |
The pattern the table makes visible: a 5 mg vial cannot deliver the 8, 9 or 12 mg trial amounts in one syringe at any of the three water volumes, because the whole vial is 5 mg. The 20 mg vial at 1 mL is the only row in which every trial figure sits under 100 units. The retatrutide calculator works any combination entered, including units back to milligrams for the "units to mg" question, and the retatrutide reconstitution page covers the water volumes per vial size in full.
Units to milligrams
The reverse conversion is the one people search for after the fact. Milligrams = units ÷ 100 × concentration in mg/mL. Forty units at 10 mg/mL is 0.4 mL and 4 mg; the same forty units at 2.5 mg/mL is 1 mg, and at 20 mg/mL it is 8 mg. A syringe reading carries no information about milligrams until the concentration is known, and the concentration is known only from the vial size and the water added to it.
What the figures omit
The trial figures come with a weekly interval, four-week steps, durations of 48 to 104 weeks, and populations defined by BMI, diabetes or cardiovascular disease. TRIUMPH-1 also came with discontinuation rates for adverse events of 4.1%, 6.9% and 11.3% across the three doses against 4.9% on placebo, which is as much a part of the record as the weight figures. A research vial carries none of those conditions, and the arithmetic above moves only the milligram figures, not their context. There is no label to supply a maximum, an indication or a stated concentration, and the export-only listings on DailyMed do not fill that gap.
Related pages
Tirzepatide dosage is the labelled comparison on this site, and semaglutide dosage the other. Cagrilintide dosage covers the other investigational incretin-era compound with a phase 3 record and no label. The store's comparison of tirzepatide and retatrutide puts the two molecules side by side, and medibact.com documents the general mixing procedure on its how to reconstitute peptides page.
The insulin syringe units how-to explains the U-100 and U-40 scales and how a milligram figure becomes a syringe reading.
What this page does not do
This page reports what the registry, the published phase 2 trial, Lilly's two 2026 releases and the public web state about retatrutide dosing, each dated, and converts the sourced figures into syringe units for three vial sizes. It does not recommend an amount, a starting point, a step or a schedule, and the trial protocols are reported as history, not as a plan. The figures without a source are labelled as such and nothing more.
Sources and dates
Opened 2026-09-18: the DailyMed SPL search for retatrutide (ten records, all "Export only", one labeler) and one of those records read in full; NCT04881760 and NCT05929066 on ClinicalTrials.gov; PMID 37366315 (Jastreboff et al., NEJM 2023); Eli Lilly's releases of 2026-05-21 and 2026-07-23 as distributed by PR Newswire; and a read of forum and vendor pages for the figures in circulation. Corrections go to the contact page.