Published by Peptide Protocols · Reviewed September 2026 · How we make these pages · Educational & research purposes only — not medical advice.
1 mL = 100 units on a U-100 insulin syringe. Formula: mg ÷ mL = mg/mL; (mcg ÷ 1000) ÷ mg/mL = mL; mL × 100 = units.
Units to draw on a U-100 insulin syringe for the common vial sizes and water volumes. Pick the row that matches your vial and the water you added.
| Vial + water | Concentration | 2.5 mg | 5 mg | 7.5 mg | 10 mg | 12.5 mg | 15 mg | 17.5 mg |
|---|---|---|---|---|---|---|---|---|
| 100 mg vial + 2 mL water | 50 mg/mL | 5 u | 10 u | 15 u | 20 u | 25 u | 30 u | 35 u |
| 100 mg vial + 5 mL water | 20 mg/mL | 12 u | 25 u | 38 u | 50 u | 62 u | 75 u | 88 u |
| 100 mg vial + 10 mL water | 10 mg/mL | 25 u | 50 u | 75 u | 100 u | 125 u | 150 u | 175 u |
| 500 mg vial + 2 mL water | 250 mg/mL | 1 u | 2 u | 3 u | 4 u | 5 u | 6 u | 7 u |
| 500 mg vial + 5 mL water | 100 mg/mL | 2 u | 5 u | 8 u | 10 u | 12 u | 15 u | 18 u |
| 500 mg vial + 10 mL water | 50 mg/mL | 5 u | 10 u | 15 u | 20 u | 25 u | 30 u | 35 u |
| 1000 mg vial + 2 mL water | 500 mg/mL | 0 u | 1 u | 2 u | 2 u | 2 u | 3 u | 4 u |
| 1000 mg vial + 5 mL water | 200 mg/mL | 1 u | 2 u | 4 u | 5 u | 6 u | 8 u | 9 u |
| 1000 mg vial + 10 mL water | 100 mg/mL | 2 u | 5 u | 8 u | 10 u | 12 u | 15 u | 18 u |
Worked example: a 100 mg vial with 2 mL of bacteriostatic water is 50 mg/mL. A 100 mg draw is 2.00 mL, which is 200 units. Change the water and every number on the syringe changes — which is the single most common reconstitution mistake. The full explanation is in How to Reconstitute Peptides.
A 500 mg vial with 5 mL of water is 100 mg/mL, so 100 mg = 1 mL = a full 100-unit syringe. With 2 mL in a 100 mg vial (50 mg/mL) it is 2 mL — two syringes. NAD+ draws are large; the water volume matters more here than for any other peptide.
Because the amounts are in milligrams, not micrograms. A 100 mg draw from a 1,000 mg vial with 10 mL of water (100 mg/mL) is exactly 1 mL; the same draw from a 100 mg vial with 2 mL would be the whole vial.
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The one formula, a BAC-water chart, and the 10 most-researched beginner peptides — the math done for you. Print it for the fridge.
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