How to reconstitute Retatrutide
Retatrutide is sold as a freeze-dried powder, most often in 5 mg, 10 mg, 20 mg, 30 mg vials. Add bacteriostatic water, let it dissolve without shaking, and the concentration is the vial amount divided by the water: 10 mg in 2 mL is 5 mg/mL. On a U-100 insulin syringe one unit is 0.01 mL, so each unit carries 50 mcg, and a 2 mg dose is 40 units.
Not approved anywhere. Phase 2 trial arms used 1 mg to 12 mg once weekly with a 2 mg to 4 mg starting dose. Nothing on this page is a dosing recommendation; the calculator converts a dose you already have into syringe units.
Retatrutide doses in syringe units (10 mg vial, 2 mL water)
| Dose | Units | mL | Doses per vial |
|---|---|---|---|
| 1 mg | 20 | 0.2 | 10 |
| 2 mg | 40 | 0.4 | 5 |
| 4 mg | 80 | 0.8 | 2 |
| 8 mg | 160 | 1.6 | 1 |
| 12 mg | 240 | 2.4 | 0 |
Vial sizes at 2 mg per dose
| Vial | Water | Concentration | Units per dose | Doses |
|---|---|---|---|---|
| 5 mg | 2 mL | 2.5 mg/mL | 80 | 2 |
| 10 mg | 2 mL | 5 mg/mL | 40 | 5 |
| 20 mg | 2 mL | 10 mg/mL | 20 | 10 |
| 30 mg | 2 mL | 15 mg/mL | 13.3 | 15 |
The dose column is in mg. Doubling the water halves the concentration and doubles the units per dose; the number of doses in the vial never changes. If a dose comes out under 5 units, use less water so it is easier to measure. If it exceeds the syringe, use more water or a bigger syringe.
Worked example
10 mg / 2 mL = 5 mg/mL = 5,000 mcg/mL. One unit = 0.01 mL = 50 mcg. 2,000 mcg / 50 mcg per unit = 40 units. The vial holds 10,000 / 2,000 = 5 doses, which at 1 per week is about 35 days.
See the general peptide calculator for the formulas, syringe sizes, and the common mg versus mcg mistakes.