Printable reference
Retatrutide Dosage Chart
Retatrutide has no approved label and therefore no approved dose, starting dose or escalation schedule. What this sheet gives you is the conversion arithmetic — mg to mL to units — plus the doses that were administered in the published phase 2 trial. Printable.
- Approval status
- None, anywhere
- U-100 barrel
- 100 units = 1 mL
- At 10 mg/mL
- 1 unit = 0.1 mg
- Phase 2 obesity trial
- 1, 4, 8, 12 mg weekly
Start with what this chart does not contain. Retatrutide (LY3437943) is an investigational triple GIP, GLP-1 and glucagon receptor agonist. No regulator anywhere has approved it, so there is no label, and with no label there is no approved dose, no approved starting dose, no approved escalation schedule, no approved interval between steps and no approved concentration. This sheet does not print any of those, because printing one would mean inventing it. If you came here for a titration ladder, the honest answer is that none exists to give you.
What it does print is arithmetic. The first table converts a dose in milligrams into a mark on a U-100 insulin barrel, at each concentration a vial of lyophilised powder commonly works out to; the second reads the same relationship backwards, from a mark you have already drawn to the milligrams it delivers; the third shows what each vial-and-water combination produces. Find your concentration along the top — it is the milligrams in the vial divided by the millilitres of bacteriostatic water you added — and read down. This conversion is dimensional analysis. It is right or wrong regardless of whether the compound should be used at all, and a ten-fold slip in it is the difference between 4 mg and 40 mg.
A U-100 barrel is graduated so 100 units equals exactly 1 mL, not 100 mg. That is the error this page exists to prevent. Any figure above 100 units is greyed: it will not fit a 1 mL insulin barrel in one draw, which is a signal that the vial was reconstituted too dilute for that figure rather than an instruction to inject twice.
The fourth table is different in kind from the other three. It reports the dose arms of a named, published clinical trial — a record of what 338 supervised participants received, with the results and the placebo arm alongside. Reporting that a trial administered 8 mg once weekly is not telling anyone to take 8 mg once weekly. Those participants were screened for eligibility, monitored throughout, and given material manufactured to pharmaceutical standard. None of those three things applies to a vial bought online.
Milligrams to units on a U-100 syringe
Read down for a dose in milligrams, across for the concentration your vial works out to. Every cell is units on a U-100 insulin barrel, with the volume beneath. These cells are identical to the ones the retatrutide calculator produces — the same function, called with the same arguments.
| Dose | 2.5 mg/mLe.g. 5 mg + 2 mL | 5 mg/mLe.g. 10 mg + 2 mL | 7.5 mg/mLe.g. 15 mg + 2 mL | 10 mg/mLe.g. 10 mg + 1 mL | 15 mg/mLe.g. 30 mg + 2 mL |
|---|---|---|---|---|---|
| 0.5 mg | 20 u0.20 mL | 10 u0.10 mL | 6.75 u0.07 mL | 5 u0.05 mL | 3.25 u0.03 mL |
| 1 mg | 40 u0.40 mL | 20 u0.20 mL | 13.25 u0.13 mL | 10 u0.10 mL | 6.75 u0.07 mL |
| 2 mg | 80 u0.80 mL | 40 u0.40 mL | 26.75 u0.27 mL | 20 u0.20 mL | 13.25 u0.13 mL |
| 3 mg | 120 u1.20 mL — won't fit | 60 u0.60 mL | 40 u0.40 mL | 30 u0.30 mL | 20 u0.20 mL |
| 4 mg | 160 u1.60 mL — won't fit | 80 u0.80 mL | 53.25 u0.53 mL | 40 u0.40 mL | 26.75 u0.27 mL |
| 6 mg | 240 u2.40 mL — won't fit | 120 u1.20 mL — won't fit | 80 u0.80 mL | 60 u0.60 mL | 40 u0.40 mL |
| 8 mg | 320 u3.20 mL — won't fit | 160 u1.60 mL — won't fit | 106.75 u1.07 mL — won't fit | 80 u0.80 mL | 53.25 u0.53 mL |
| 10 mg | 400 u4.00 mL — won't fit | 200 u2.00 mL — won't fit | 133.25 u1.33 mL — won't fit | 100 u1.00 mL | 66.75 u0.67 mL |
| 12 mg | 480 u4.80 mL — won't fit | 240 u2.40 mL — won't fit | 160 u1.60 mL — won't fit | 120 u1.20 mL — won't fit | 80 u0.80 mL |
Rows run from 0.5 mg to 12 mg because that span covers every dose administered in either published phase 2 trial — 1, 4, 8 and 12 mg in the obesity trial, and 0.5 mg as the lowest arm of the type 2 diabetes trial — plus the intermediate figures needed to read a vial. Tabulating a figure is not recommending it, and no row on this table is a dose anyone should select. Greyed cells exceed the 100 units a 1 mL U-100 barrel holds.
Units back to milligrams — what the mark you drew delivers
The same relationship in reverse, for checking a draw rather than planning one. Find the mark on the barrel down the left and your concentration across the top; the cell is milligrams. Use it to check a figure someone else gave you before you inject it.
| Units drawn | 2.5 mg/mLmg delivered | 5 mg/mLmg delivered | 7.5 mg/mLmg delivered | 10 mg/mLmg delivered | 15 mg/mLmg delivered |
|---|---|---|---|---|---|
| 1 u0.01 mL | 0.025 | 0.05 | 0.075 | 0.1 | 0.15 |
| 2 u0.02 mL | 0.05 | 0.1 | 0.15 | 0.2 | 0.3 |
| 3 u0.03 mL | 0.075 | 0.15 | 0.225 | 0.3 | 0.45 |
| 4 u0.04 mL | 0.1 | 0.2 | 0.3 | 0.4 | 0.6 |
| 5 u0.05 mL | 0.125 | 0.25 | 0.375 | 0.5 | 0.75 |
| 6 u0.06 mL | 0.15 | 0.3 | 0.45 | 0.6 | 0.9 |
| 8 u0.08 mL | 0.2 | 0.4 | 0.6 | 0.8 | 1.2 |
| 10 u0.10 mL | 0.25 | 0.5 | 0.75 | 1 | 1.5 |
| 12 u0.12 mL | 0.3 | 0.6 | 0.9 | 1.2 | 1.8 |
| 15 u0.15 mL | 0.375 | 0.75 | 1.125 | 1.5 | 2.25 |
| 20 u0.20 mL | 0.5 | 1 | 1.5 | 2 | 3 |
| 25 u0.25 mL | 0.625 | 1.25 | 1.875 | 2.5 | 3.75 |
| 30 u0.30 mL | 0.75 | 1.5 | 2.25 | 3 | 4.5 |
| 35 u0.35 mL | 0.875 | 1.75 | 2.625 | 3.5 | 5.25 |
| 40 u0.40 mL | 1 | 2 | 3 | 4 | 6 |
| 50 u0.50 mL | 1.25 | 2.5 | 3.75 | 5 | 7.5 |
| 60 u0.60 mL | 1.5 | 3 | 4.5 | 6 | 9 |
| 70 u0.70 mL | 1.75 | 3.5 | 5.25 | 7 | 10.5 |
| 80 u0.80 mL | 2 | 4 | 6 | 8 | 12 |
| 90 u0.90 mL | 2.25 | 4.5 | 6.75 | 9 | 13.5 |
| 100 u1.00 mL | 2.5 | 5 | 7.5 | 10 | 15 |
A unit is a volume, never a dose. The identical mark on the identical barrel delivers a different number of milligrams from every vial in this table, which is why any instruction phrased only in units — "draw 25" — is meaningless until the concentration is stated alongside it.
Reconstitution — what each vial and water volume produces
Vial mass divided by the bacteriostatic water added gives the concentration; everything else on the row follows from it. This table selects nothing. It tells you what you have made.
| Vial + BAC water | Concentration | 1 unit mark | 10 unit marks | Whole vialunits | Most one barrel can drawat 100 u |
|---|---|---|---|---|---|
| 5 mg + 1 mL | 5 mg/mL | 0.05 mg | 0.5 mg | 100 uone barrel | 5 mg |
| 5 mg + 2 mL | 2.5 mg/mL | 0.025 mg | 0.25 mg | 200 umore than one barrel | 2.5 mg |
| 5 mg + 3 mL | 1.67 mg/mL | 0.0167 mg | 0.1667 mg | 300 umore than one barrel | 1.67 mg |
| 10 mg + 1 mL | 10 mg/mL | 0.1 mg | 1 mg | 100 uone barrel | 10 mg |
| 10 mg + 2 mL | 5 mg/mL | 0.05 mg | 0.5 mg | 200 umore than one barrel | 5 mg |
| 10 mg + 3 mL | 3.33 mg/mL | 0.0333 mg | 0.3333 mg | 300 umore than one barrel | 3.33 mg |
| 15 mg + 1 mL | 15 mg/mL | 0.15 mg | 1.5 mg | 100 uone barrel | 15 mg |
| 15 mg + 2 mL | 7.5 mg/mL | 0.075 mg | 0.75 mg | 200 umore than one barrel | 7.5 mg |
| 15 mg + 3 mL | 5 mg/mL | 0.05 mg | 0.5 mg | 300 umore than one barrel | 5 mg |
| 20 mg + 1 mL | 20 mg/mL | 0.2 mg | 2 mg | 100 uone barrel | 20 mg |
| 20 mg + 2 mL | 10 mg/mL | 0.1 mg | 1 mg | 200 umore than one barrel | 10 mg |
| 20 mg + 3 mL | 6.67 mg/mL | 0.0667 mg | 0.6667 mg | 300 umore than one barrel | 6.67 mg |
| 30 mg + 1 mL | 30 mg/mL | 0.3 mg | 3 mg | 100 uone barrel | 30 mg |
| 30 mg + 2 mL | 15 mg/mL | 0.15 mg | 1.5 mg | 200 umore than one barrel | 15 mg |
| 30 mg + 3 mL | 10 mg/mL | 0.1 mg | 1 mg | 300 umore than one barrel | 10 mg |
Vial masses here are sizes this material is commonly supplied in. They are not label strengths, because there is no label, and they are not recommendations — compounded retatrutide has no approved concentration either. The last column is a ceiling imposed by the instrument, not a maximum dose: it is simply what 100 units holds at that concentration. The lyophilised cake displaces a negligible volume at these masses, so the final volume is taken to be the water added — the one place this arithmetic is an approximation, and it is stated rather than hidden. How much water you add changes no milligram figure: more water spreads a given dose over more marks, less water keeps the injection volume down.
Doses administered in the phase 2 obesity trial
A transcription of published results, not a dosing table. The left column is the dose group as the paper reports it; the second column is how the arms were randomised, in the paper’s own bracket notation. The syringe columns are there so a reported figure can be located on the tables above.
| Dose group | Randomised asNEJM 2023, verbatim | Weight changeLS mean, 24 weeks | Weight changeLS mean, 48 weeks | Unitsat 5 mg/mL | Unitsat 10 mg/mL |
|---|---|---|---|---|---|
| 1 mgonce weekly | 1 mg | -7.2% | -8.7% | 20 u0.20 mL | 10 u0.10 mL |
| 4 mgonce weekly | 4 mg [initial dose, 2 mg] and 4 mg [initial dose, 4 mg] | -12.9% | -17.1% | 80 u0.80 mL | 40 u0.40 mL |
| 8 mgonce weekly | 8 mg [initial dose, 2 mg] and 8 mg [initial dose, 4 mg] | -17.3% | -22.8% | 160 u1.60 mL — won't fit | 80 u0.80 mL |
| 12 mgonce weekly | 12 mg [initial dose, 2 mg] | -17.5% | -24.2% | 240 u2.40 mL — won't fit | 120 u1.20 mL — won't fit |
| Placeboonce weekly | placebo | -1.6% | -2.1% | — | — |
Doses and outcomes from Jastreboff AM, et al. Triple-Hormone-Receptor Agonist Retatrutide for Obesity — A Phase 2 Trial. N Engl J Med 2023;389(6):514–526 (PMID 37366315). Retatrutide is investigational and is not approved for use anywhere. The 4 mg and 8 mg rows are pooled: each dose was studied with two different initial doses and the paper reports the combined groups. The abstract states the initial dose of each arm but no interval between steps, and the ClinicalTrials.gov record for NCT04881760 describes the sequence of the 12 mg arm without stating one either — so no escalation schedule, step interval or titration ladder is given on this page. There is none to give.
Frequently asked questions
- What is the recommended dose of retatrutide?
- There is not one, and any page that gives you a figure has made it up. A recommended dose is something a regulator approves when it approves a label, and retatrutide has no label — no FDA approval, no EMA authorisation, nothing anywhere in the world, for any indication. What exists is a record of what was given in clinical trials: in the phase 2 obesity trial, once-weekly subcutaneous maintenance doses of 1 mg, 4 mg, 8 mg or 12 mg over 48 weeks. That is a description of a study, given under supervision to 338 screened participants, and it is not a recommendation to anyone outside it.
- Is there a retatrutide titration or escalation schedule?
- No approved one exists, so this chart does not print one. The published phase 2 trial does report initial doses — the paper labels its arms "4 mg [initial dose, 2 mg]", "8 mg [initial dose, 4 mg]", "12 mg [initial dose, 2 mg]" and so on — and the ClinicalTrials.gov record for NCT04881760 says the 12 mg arm received "2 mg LY3437943 starting dose followed by 4 mg LY3437943, 8 mg LY3437943 and then 12 mg LY3437943". Neither source states how long each step lasted. A ladder without intervals is not a schedule, and filling the intervals in from a different drug’s label would be inventing the most important part of it.
- Is retatrutide FDA approved? There are retatrutide entries in DailyMed.
- It is not approved, and those entries are not what they look like. As of September 2026 DailyMed carries ten retatrutide SPLs, all ten filed by one registrant — Guangzhou Yixin Cross-border E-commerce Co., Ltd. — and all ten under the marketing category "Export only". An export-only listing registers a product that may not be lawfully sold in the United States; FDA does not review or approve its content, and the registrant writes the text. One of those listings contains a four-step weekly titration headed "Typical weekly dosing schedule (example shown — follow your prescriber)". Those steps appear in no published trial. This page does not reproduce them, and a DailyMed entry is not evidence of approval.
- How many units is 4 mg of retatrutide?
- It depends entirely on the concentration, which is why a unit figure quoted without one is worthless. At 5 mg/mL — a 10 mg vial reconstituted with 2 mL — 4 mg is 0.80 mL, which is 80 units. At 10 mg/mL, the same 10 mg vial with 1 mL, the same 4 mg becomes 40 units. Identical milligrams, half the marks. Work out your own concentration first: milligrams in the vial divided by millilitres of bacteriostatic water added.
- How much bacteriostatic water should I add to a retatrutide vial?
- No volume is correct, because there is no approved concentration for retatrutide and none for compounded retatrutide either. The water changes the concentration and nothing else — the milligrams in the vial are fixed the moment it is filled. The trade-off is only about readability on the barrel: at 2.5 mg/mL, 12 mg works out to 480 units, 4.80 mL, nearly five full barrels and undrawable in one go; at 15 mg/mL the same 12 mg is 80 units. Dilute enough that your figure lands on marks you can read, concentrated enough that it fits one barrel.
- How do I convert retatrutide milligrams to syringe units?
- Three steps. Divide the vial mass in milligrams by the bacteriostatic water in millilitres to get the concentration in mg/mL. Divide your figure in milligrams by that concentration to get the volume in millilitres. Multiply by 100, because a U-100 barrel is graduated so 100 units equals 1 mL. A 10 mg vial in 2 mL is 5 mg/mL, so one unit mark carries 0.05 mg and 4 mg is 0.80 mL — 80 units. The single most expensive mistake is reading the barrel as if 100 units were 100 mg; it is a hundredfold error.
- Is retatrutide stronger than tirzepatide or semaglutide?
- Nobody knows, because no trial has compared them head to head. Retatrutide’s phase 2 obesity trial reported least-squares mean weight change at 48 weeks of −22.8% in the combined 8 mg group and −24.2% in the 12 mg group, against −2.1% for placebo. Those numbers are larger than the figures published for approved agents, but comparing across separate trials with different populations, durations and endpoints is not a valid comparison and cannot support a ranking. Semaglutide and tirzepatide also carry phase 3 programmes, approved labels and post-marketing surveillance behind them. Retatrutide carries a phase 2 result and nothing else.
- How long does a reconstituted retatrutide vial last?
- This chart answers the arithmetic half of that question and refuses the other half. How many whole doses a vial contains is vial mass divided by dose, rounded down, and the water volume makes no difference to it. How long the solution remains usable after water is added is a beyond-use date, and a beyond-use date is established by stability testing on a specific formulation in a specific container. No such data has been published for retatrutide, so no figure in days is given here. Anyone quoting you one — 28 days, 56 days — is quoting it from a different drug.
Sources
- [1]Jastreboff AM, Kaplan LM, Frías JP, et al. Triple-Hormone-Receptor Agonist Retatrutide for Obesity — A Phase 2 Trial. N Engl J Med. 2023;389(6):514–526. PMID 37366315. Dose arms and weight-change figures taken verbatim from the abstract
- [2]ClinicalTrials.gov, NCT04881760 — A Study of LY3437943 in Participants Who Have Obesity or Are Overweight. Arm descriptions, including the starting-dose sequence of the 12 mg arm
- [3]Rosenstock J, Frias J, Jastreboff AM, et al. Retatrutide, a GIP, GLP-1 and glucagon receptor agonist, for people with type 2 diabetes: a phase 2 trial. Lancet. 2023;402(10401):529–544. PMID 37385280. Source of the 0.5 mg arm, the lowest dose studied
- [4]DailyMed SPL — SALKALLI (RETATRUTIDE LYOPHILIZED POWDER 10MG), Guangzhou Yixin Cross-border E-commerce Co., Ltd., set id 4302eb14-2065-d22b-e063-6394a90a9dcf. Marketing category "Export only": not an FDA-approved label
- [5]DailyMed SPL search, drug_name=retatrutide — the full set of ten listings, all from the same registrant
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Educational reference, not medical advice, and not a dosing protocol. Retatrutide is investigational and approved by no regulator anywhere; no approved dose, starting dose, escalation schedule or concentration exists, and none is stated here. This sheet converts units of measurement and reports doses administered in a published trial. Confirm the scale printed on your barrel and the mass printed on your vial before drawing. alphahealthfinder.com