Tirzepatide 20 mg reconstituted with 1.5 mL
Concentration
13.33mg/mL
- Per insulin unit
- 133.3 mcg
- Solution in vial
- 150 u
- 12.5 mg draw
- 93.8 u
Math utility only — not medical advice. Not a recommended dose.
Units per dose at 13.33 mg/mL
Insulin syringes are graduated in hundredths of a millilitre, so units = mL × 100 on a U-100, U-50 or U-30 barrel alike.
| Dose | Volume | U-100 units | Fits | Doses per vial |
|---|---|---|---|---|
| 2.5 mg | 0.188 mL | 18.8 u | U-30 | 8 |
| 5 mg | 0.375 mL | 37.5 u | U-50 | 4 |
| 7.5 mg | 0.563 mL | 56.3 u | U-100 | 2 |
| 10 mg | 0.75 mL | 75 u | U-100 | 2 |
| 12.5 mg | 0.938 mL | 93.8 u | U-100 | 1 |
| 15 mg | 1.125 mL | 112.5 u | split draw | 1 |
Amber rows exceed 100 units — more than one full U-100 barrel. That dose needs a larger draw or a stronger mix (less water).
How this is calculated
1 · Concentration
20 mg ÷ 1.5 mL = 13.33 mg/mL
The peptide mass never changes — bacteriostatic water only sets how concentrated the solution is, and therefore how far the plunger travels.
2 · Volume for a 12.5 mg dose
12.5 mg ÷ 13.33 mg/mL = 0.938 mL
3 · Insulin units
0.938 mL × 100 = 93.8 units
Every unit on the barrel carries 133.3 mcg at this concentration, so misreading by one unit is a 133.3 mcg error.
See it on a real syringe
The interactive calculator draws this 13.33 mg/mL mix on a scaled U-100 barrel, shows when a draw lands exactly on a printed tick, and works backwards from a target dose to the water volume that makes it land cleanly.
Open the interactive calculator →Common questions
- How much bacteriostatic water for a 20 mg Tirzepatide vial?
- Adding 1.5 mL of bacteriostatic water to a 20 mg Tirzepatide vial yields 13.33 mg/mL — 133.3 mcg in every insulin unit. The reconstituted vial holds 150 units of solution in total.
- How many units is a 12.5 mg dose of Tirzepatide at 20 mg in 1.5 mL?
- 12.5 mg is 0.938 mL of this mix, which is 93.8 units on a U-100 insulin syringe (a U-100 barrel is enough).
- How many 12.5 mg doses does a 20 mg vial give?
- A 20 mg vial contains 1 full 12.5 mg doses. Using more or less bacteriostatic water changes the units you draw, never the number of doses in the vial.