Units measure volume
Almost all insulin syringes sold today are U-100, which means 100 units fill 1 mL. One unit is 0.01 mL. The marks say nothing about how much drug is in the liquid. That depends on the concentration of your vial.
The three common sizes
Reading the draw
- Hold the syringe at eye level with the needle pointing up.
- Tap out air bubbles. A bubble takes the place of liquid and shortens the dose.
- Read the edge of the rubber stopper nearest the needle.
- Count from the nearest numbered line. Check whether each small line is 1 unit or 2.
Picking a size
Use the smallest syringe that holds your draw. Smaller syringes have wider spacing between marks, so the same error in where you stop is a smaller error in dose.
To turn a dose into units, use the peptide calculator.
Common questions
How many units are in 1 mL?
On a U-100 insulin syringe, 100 units is 1 mL. So 10 units is 0.1 mL and 1 unit is 0.01 mL.
Is a 0.5 mL syringe the same as a 50-unit syringe?
Yes, for U-100 syringes. A 0.3 mL syringe holds 30 units, a 0.5 mL syringe holds 50 units, and a 1 mL syringe holds 100 units.
Which part of the plunger do I read?
Read the edge of the rubber stopper nearest the needle, where it meets the liquid, with the syringe at eye level.