P21 (P021) Dosing & Reconstitution Chart
How many insulin-syringe units to draw for P21 (P021), based on how much bacteriostatic water you add to a 5 mg vial. Every number below is on a U-100 (100 units = 1 mL) syringe and matches our calculator.
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| Water added | Concentration | 250 mcg dose | 500 mcg dose | 800 mcg dose | 1000 mcg dose |
|---|---|---|---|---|---|
| 1 mL | 5 mg/mL | 5 u | 10 u | 16 u | 20 u |
| 2 mL | 2.5 mg/mL | 10 u | 20 u | 32 u | 40 u |
| 3 mL | 1.667 mg/mL | 15 u | 30 u | 48 u | 60 u |
| 5 mL | 1 mg/mL | 25 u | 50 u | 80 u | 100 u |
Cells show units to draw on a U-100 insulin syringe.
Calculate your exact P21 (P021) dose
Pre-filled with P21 (P021)’s commonly cited vial and dose. Change any field to match your vial — it shows the exact units, concentration, and doses per vial.
Add 2 mL of bacteriostatic water to your 5 mg vial. That gives you about 10 doses of 500 mcg. For each dose, draw 20 units into a 100-unit insulin syringe.
P21 (P021) dosing FAQ
How many units of P21 (P021) should I draw?
Reconstituting a 5 mg vial of P21 (P021) with 2 mL of bacteriostatic water gives 2.5 mg/mL. A 500 mcg dose is about 20 units on a U-100 insulin syringe, roughly 10 doses per vial. This is a commonly cited example for context, not medical advice.
How much bacteriostatic water do I add to P21 (P021)?
There is no single correct amount. More water makes each dose a larger, easier-to-measure volume; less water makes it more concentrated. The chart above shows the units for 1–5 mL — 2 mL is a common choice for a 5 mg vial.
How many doses are in a 5 mg P21 (P021) vial?
At a 500 mcg dose, a 5 mg vial holds about 10 doses. Larger doses mean fewer doses per vial, and the amount of water you add does not change this.