basics4 minupdated 2026-05-14
Reading a U-100 insulin syringe
Units, mL, and micrograms — how the tick marks on a 0.3 mL or 0.5 mL insulin syringe translate to a research dose.
Unit conversion
U-100 means 100 units per 1 mL. 1 unit = 0.01 mL.
10 units = 0.1 mL. 25 units = 0.25 mL. 50 units = 0.5 mL.
Micrograms delivered = units × 0.01 × concentration (mg/mL) × 1000.
Example: 20 units of a 2.5 mg/mL solution = 20 × 0.01 × 2.5 × 1000 = 500 mcg.
Syringe sizing
0.3 mL syringes have the finest gradations (half-unit marks common) — best for microdoses under 30 units.
0.5 mL syringes are the everyday workhorse for research volumes up to 50 units.
1 mL insulin syringes exist but the tick spacing is coarser — save them for larger volume draws.
Research use only
This guide is educational reference material — not medical advice, not a prescription, and not an endorsement of self-administration.