40 mg vial
Retatrutide 40 mg vial: how to reconstitute it
What a 40 mg vial of Retatrutide becomes once it is mixed, and what each dose reported in the sources draws to on a syringe. Every figure is arithmetic on the vial size in the heading — none of it is a recommendation, and the doses are the ones our sources describe rather than ones we picked.
Leading with
40 mg + 2 mL bacteriostatic water = 20 mg/mL
Chosen because it puts the reported doses on readable marks of a 1 mL U-100 syringe. Other volumes are perfectly valid — the dilution table further down covers them, and the concentration changes what every dose draws to.
What each reported dose draws to
At 20 mg/mL, on a 1 mL U-100 syringe. Every row names the source it came from, and a trial protocol and a community convention are not the same kind of information.
| Goal | Dose | Units | Doses in this vial | Source |
|---|---|---|---|---|
| Phase 2 starting doseOnce weekly · Subcutaneous | 2 mg | 10 units | 20 | Clinical trial |
| Phase 2 escalation and maintenance armsOnce weekly, escalated in steps · Subcutaneous | 4 mg – 12 mg | 20 units – 60 units | 10 | Clinical trial |
Check every figure against the vial in front of you before drawing. Vials are filled with an overage and labels are not a guarantee. Change any of these numbers in the calculator.
Week by week
Published schedules only. Most compounds on this site have no week-by-week schedule from any source, and where that is the case this section does not appear rather than being filled in.
Reported community progression
Community practice| Week | Dose | Units | Frequency |
|---|---|---|---|
| 1–4 | 2 mg | 10 units | Once daily |
| 5–8 | 4 mg | 20 units | Once daily |
| 9–12 | 6 mg | 30 units | Once daily |
| 13+ | 8 mg | 40 units | Once daily |
A progression described in community sources, not a finding. No dose-ranging study establishes these steps, and the compilation they come from contained arithmetic errors in its own syringe figures — so the doses are reproduced and none of its unit conversions are.
What the whole schedule costs
Vials of this size needed to work through each step, at 2 mL per vial. The dose changes as you go, so this is not one number times a number of weeks — it is each step costed separately and added up.
Reported community progression
| Week | Dose | Doses | 40 mg vials |
|---|---|---|---|
| 1–4 | 2 mg | 28 | 2 |
| 5–8 | 4 mg | 28 | 3 |
| 9–12 | 6 mg | 28 | 5 |
| 13+ | 8 mg | — | ongoing |
Reaching the end of the defined steps takes 10 vials of 40 mg over 12 weeks, and the last step continues indefinitely, so that is a floor rather than a total.
Steps whose dose exceeds this vial are marked rather than counted — at that point a larger vial is the answer, not more small ones. Nothing here accounts for a dropped vial, a held step or a dose your prescriber changes, all of which happen.
If you add a different amount of water
The same 40 mg of compound, at four common volumes. More water means a larger, easier-to-measure draw of a weaker solution; less water means the opposite. The amount of compound you inject is identical in every row — only the volume carrying it changes.
| Water added | Concentration | 2 mg draws to |
|---|---|---|
| 1 mL | 40 mg/mL | 5 units units · 0.05 mL |
| 2 mLshown above | 20 mg/mL | 10 units units · 0.1 mL |
| 3 mL | 13.333 mg/mL | 15 units units · 0.15 mL |
| 5 mL | 8 mg/mL | 25 units units · 0.25 mL |
Storage
Before mixing
Refrigerated at 2–8 °C, protected from light and moisture.
After mixing
Refrigerated at 2–8 °C. Do not freeze.
Other vial sizes
The same compound, different arithmetic.
Arithmetic on the vial size named above and the doses our sources report. Nothing here is a recommendation, a protocol or medical advice, and no clinician has reviewed it. Speak to a licensed healthcare provider before acting on any of it.
Sources for the doses above are listed in full on the Retatrutide profile, each with the trial or label it came from.