Retatrutide Reconstitution Calculator
BAC water, concentration & dose-to-units charts for Reta
Work out how much bacteriostatic water to add to a retatrutide ("Reta") vial and what each dose becomes in syringe units, using the charts below — for example, a 10 mg vial in 2 mL of water is 5 mg/mL, so a 2 mg dose is 0.4 mL, or 40 units on a U-100 syringe. Retatrutide is investigational; always confirm against the product label and your prescriber before injecting.
How retatrutide reconstitution works
Retatrutide is supplied as a freeze-dried (lyophilized) powder that you dissolve with bacteriostatic water before measuring a dose. The resulting concentration is simply the vial strength divided by the water you add — a 10 mg vial in 2 mL of water is 5 mg/mL.
Once you know the concentration, your dose volume is the dose divided by the concentration, and on a U-100 insulin syringe that volume × 100 gives the number of unit marks to draw. Adding more water lowers the concentration and makes each dose a larger, easier-to-measure volume — useful for small early doses like 1–2 mg.
Reconstitution chart: concentration by retatrutide vial size and water added
| Vial size | +1 mL | +2 mL | +3 mL | +5 mL |
|---|---|---|---|---|
| 5 mg | 5 mg/mL | 2.5 mg/mL | 1.67 mg/mL | 1 mg/mLBest |
| 10 mg | 10 mg/mL | 5 mg/mL | 3.33 mg/mL | 2 mg/mL |
| 15 mg | 15 mg/mL | 7.5 mg/mL | 5 mg/mL | 3 mg/mL |
| 20 mg | 20 mg/mL | 10 mg/mL | 6.67 mg/mL | 4 mg/mL |
| 30 mg | 30 mg/mL | 15 mg/mL | 10 mg/mL | 6 mg/mL |
Retatrutide dose to syringe units (by concentration)
| Weekly dose | 5 mg/mL | 10 mg/mL | 15 mg/mL |
|---|---|---|---|
| 1 mg | 0.2 mL → 20 | 0.1 mL → 10 | 0.07 mL → 7Best |
| 2 mg | 0.4 mL → 40 | 0.2 mL → 20 | 0.13 mL → 13 |
| 4 mg | 0.8 mL → 80 | 0.4 mL → 40 | 0.27 mL → 27 |
| 6 mg | 1.2 mL → 120* | 0.6 mL → 60 | 0.4 mL → 40 |
| 8 mg | 1.6 mL → 160* | 0.8 mL → 80 | 0.53 mL → 53 |
| 12 mg | 2.4 mL → 240* | 1.2 mL → 120* | 0.8 mL → 80 |
How to reconstitute a retatrutide vial
Dosing, storage & safety
Retatrutide is a once-weekly injection that is escalated slowly to limit nausea — Phase 3 TRIUMPH protocols stepped up over several months toward 8–12 mg. This calculator only does the reconstitution and unit math; it does not decide your titration schedule, which should come from a clinician.
Bacteriostatic water contains benzyl alcohol as a preservative, so a reconstituted vial can be used for multiple draws; keep it refrigerated and labeled with its concentration and date. Because retatrutide is investigational and not approved, only obtain and use it under appropriate medical or research supervision, and ask your pharmacist when in doubt.
Frequently Asked Questions
It depends on the concentration you want. 10 mg in 1 mL gives 10 mg/mL; in 2 mL gives 5 mg/mL; in 3 mL gives about 3.33 mg/mL. For small early doses like 1–2 mg, more water (a lower concentration) makes the dose an easier number of units to measure. Use the reconstitution chart above.
At 5 mg/mL, 2 mg is 0.4 mL, or 40 units on a U-100 insulin syringe. At 10 mg/mL it is 0.2 mL (20 units). Units = (dose ÷ concentration) × 100.
Add bacteriostatic water down the vial wall, swirl gently until clear (do not shake), then label with the concentration and date and refrigerate. Use the step-by-step guide and chart above, and confirm against the product label.
There is no single best concentration — pick one that keeps your usual dose under 100 units (a full 1 mL syringe). Higher doses (8–12 mg) usually need a higher concentration like 10–15 mg/mL so the volume stays measurable.
No. As of 2026 retatrutide is investigational and only studied in clinical trials. This page provides reconstitution math for educational purposes and does not endorse non-prescribed use.
Yes. Shotlee stores your vial concentration, logs each dose and side effect, and sends reminders so you do not have to recompute every week. It is free.
Save Your Retatrutide Plan in Shotlee
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