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.
Open the pocket version (works offline on your phone) →
Each one is preset to that peptide’s usual vial and water, with a full reconstitution chart for the common combinations and the questions people actually ask.
A 5 mg vial with 2 mL of bacteriostatic water is 2.5 mg/mL. A 250 mcg draw is 0.1 mL, which is 10 units. Add 3 mL instead and the same 250 mcg becomes 15 units — the peptide has not changed, only how much of it is in each tick of the syringe. If you want the long version with the mistakes to avoid, read How to Reconstitute Peptides: The Math, Made Simple.
Units to draw for the round-number targets most research references use.
| Vial + water | Concentration | 100 mcg | 250 mcg | 500 mcg | 1 mg | 2 mg |
|---|---|---|---|---|---|---|
| 5 mg vial + 1 mL water | 5 mg/mL | 2 u | 5 u | 10 u | 20 u | 40 u |
| 5 mg vial + 2 mL water | 2.5 mg/mL | 4 u | 10 u | 20 u | 40 u | 80 u |
| 5 mg vial + 3 mL water | 1.66667 mg/mL | 6 u | 15 u | 30 u | 60 u | 120 u |
| 10 mg vial + 1 mL water | 10 mg/mL | 1 u | 2 u | 5 u | 10 u | 20 u |
| 10 mg vial + 2 mL water | 5 mg/mL | 2 u | 5 u | 10 u | 20 u | 40 u |
| 10 mg vial + 3 mL water | 3.33333 mg/mL | 3 u | 8 u | 15 u | 30 u | 60 u |
It divides the vial strength (mg) by the water you add (mL) to get a concentration in mg/mL, then divides your target draw by that concentration to get millilitres, and multiplies by 100 to convert to units on a U-100 insulin syringe. Every peptide reconstitution calculator does exactly this.
Any volume works mathematically; what changes is how many units each draw is. Researchers usually choose a volume that makes the intended draw land on an easy-to-read syringe line (10, 20, 25, 50 units) and stays under one full syringe. The per-peptide charts on this site show the common combinations.
A U-100 insulin syringe is marked in units: 100 units = 1 mL, so each unit is 0.01 mL. Mixing the two up is the most common reconstitution error.
Yes — free, no sign-up, and there is a downloadable offline version. It is for research and educational purposes only.
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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.
🎁 Send me the free cheat sheet →Every cheat sheet in the shop includes the Universal Excel Logbook — it auto-calculates reconstitution and tick marks for 38+ peptides and keeps a dated record of each vial.
Browse the cheat sheets on Etsy →