How do I convert mg or mcg into units on a U-100 syringe?
Updated: 2026-09-09 · Reconstitution and syringes
Short answer
A U-100 syringe holds 100 units in 1 ml, so each unit is 0.01 ml. The conversion takes two steps: work out the vial concentration in mg per ml, then divide the amount you want to draw by that concentration to get millilitres, and multiply by 100 to get units.
In plain English
- 1 ml = 100 units. 0.1 ml = 10 units.
- U-100 'units' are syringe volume graduations (100 marks per ml), not universal dose units for any peptide or drug.
- 1 mg = 1000 mcg — the most common 1000x error.
- Concentration = vial mg ÷ ml of water.
- Units = (desired mg ÷ concentration) × 100.
What we know
- Arithmetic example: a 10 mg vial with 2 ml is 5 mg/ml; drawing 0.5 mg equals 0.1 ml, or 10 units.
- The site calculator runs these steps with your vial's real concentration.
What we don't know yet
- How many milligrams suit a specific person — this page does not calculate doses.
The example is conversion arithmetic, not a recommended dose.