Reading a U-100 insulin syringe
What the 'units' on an insulin syringe measure and how they relate to mL.
Research peptides are usually measured with U-100 insulin syringes. The markings are in units, and on a U-100 syringe 100 units = 1 mL, so 10 units = 0.1 mL and 1 unit = 0.01 mL.
Syringe units are only volume. How much peptide 10 units holds depends on the concentration of the vial, which depends on how much water was added (see the reconstitution lesson). Syringes come in 0.3 mL (30-unit), 0.5 mL (50-unit) and 1 mL (100-unit) sizes; smaller syringes have finer markings and make small volumes easier to read.
Don't confuse U-100 with U-40 syringes (used for some veterinary insulins), where the markings mean something different.
- U-100: 100 units = 1 mL.
- Units are volume; the amount of peptide depends on concentration.
- Smaller syringes make small volumes easier to read.
Quick check
100 units = 1 mL, so 25 units = 0.25 mL.
Reconstitution calculator · Mixing guides
General education, not medical advice. Nothing here recommends using any compound or amount.