Short answer: 2 mL of bacteriostatic water in a 15 mg retatrutide vial makes 7.5 mg/mL. On a U-100 insulin syringe (1 mL = 100 units), every 10 units then holds 750 mcg. More water gives a weaker solution and a bigger draw for the same amount; the amount in the vial stays 15 mg.
| Water added | Concentration | Per 10 units | Per 1 unit |
|---|---|---|---|
| 1 mL | 15 mg/mL | 1.5 mg | 150 mcg |
| 2 mL | 7.5 mg/mL | 750 mcg | 75 mcg |
| 3 mL | 5 mg/mL | 500 mcg | 50 mcg |
| 5 mL | 3 mg/mL | 300 mcg | 30 mcg |
The amounts below are examples to show the conversion, not doses. How much to take is a decision for you and your prescriber.
| Water added | 1 mg | 2 mg | 4 mg |
|---|---|---|---|
| 1 mL | 6.7 units | 13.3 units | 26.7 units |
| 2 mL | 13.3 units | 26.7 units | 53.3 units |
| 3 mL | 20 units | 40 units | 80 units |
| 5 mL | 33.3 units | 66.7 units | over 1 mL |
A 15 mg vial holds 15 draws of 1 mg, 7.5 draws of 2 mg, 3.8 draws of 4 mg, no matter how much water you add.
15 mg ÷ 2 mL = 7.5 mg/mLamount ÷ 7.5 mg/mL = mLmL × 100 = unitsFor a different water volume or amount, the free peptide reconstitution calculator works backwards from the amount you want and suggests a water volume that lands on a clean syringe mark.
Retatrutide 5 mg · Retatrutide 10 mg · Retatrutide 20 mg · Retatrutide 30 mg · Retatrutide 60 mg
Half-life, time to peak and sources are on the main Retatrutide guide.