Cartridge pens and insulin syringes are marked in units on a U-100 scale. Understanding what a unit is makes the mg and ml math straightforward.
What a unit is
On a U-100 scale, 1 unit = 0.01 ml. So 10 units is 0.10 ml, 50 units is 0.50 ml, and the full 100 units is 1.00 ml. A standard 3 ml cartridge therefore holds 300 units of liquid volume. The Gansulin pen dials from 1 to 60 units, one click each.
Units measure volume, not strength
A unit is a volume, not an amount of compound. How much compound is in that volume depends on the concentration you mixed. Concentration is simply the milligrams of powder divided by the milliliters of diluent you added.
From units to milligrams
Here is a worked example. Suppose you reconstitute a 10 mg vial with 1 ml of bacteriostatic water:
- Concentration = 10 mg ÷ 1 ml = 10 mg/ml.
- Draw 10 units = 0.10 ml = 0.10 × 10 = 1 mg.
- Draw 5 units = 0.05 ml = 0.5 mg.
Change the water volume and the concentration changes with it. Add 2 ml instead of 1 ml and the same vial becomes 5 mg/ml, so 10 units now equals 0.5 mg.
Let the calculator do it
Our free reconstitution calculator converts between mg, ml and units instantly, and the protocol planner estimates how many vials a schedule needs. Pair it with the right bacteriostatic water and cartridges.
PreppinPeppers sells laboratory hardware and consumables for research, educational, and demonstration use only. This article is general educational information about equipment and does not describe, recommend, or instruct the use of any peptide or other substance in humans or animals. Nothing here is medical advice.