Insulin Syringe Units Explained (U-100, 0.3/0.5/1 ml)
Updated 2026-08-20
What a unit actually is
On a U-100 syringe, 100 units = 1 ml. A unit is a volume marking, nothing more: 10 units = 0.1 ml, 50 units = 0.5 ml. How many mcg of peptide that volume contains depends entirely on your reconstitution — which is why the same '10 units' can be 125 mcg for one person and 500 mcg for another.
0.3, 0.5 and 1 ml syringes
All three use the same U-100 scale — a dose of 10 units is the identical volume on each. Smaller syringes (0.3 ml = 30 units max) just have a shorter, finer scale that is easier to read for small doses. For typical peptide doses under 30 units, a 0.3 or 0.5 ml syringe with half-unit markings gives the most precision.
Converting units to mcg
mcg per unit = (vial mg × 1000) ÷ (water ml × 100). Example: 5 mg vial + 2.5 ml water → 5000 ÷ 250 = 20 mcg per unit. A 300 mcg dose is then 15 units. Our calculator shows the mcg-per-unit figure for every combination so you can sanity-check any dose in your head.
Educational reference only — not medical advice. Consult a licensed healthcare provider.