Peptide Reconstitution Calculator
Vial amount, water volume, target dose — get the concentration, the mL to draw, and the exact mark on an insulin syringe. The math is shown, not hidden.
10 mg in 2 mL of bacteriostatic water = 5000 mcg/mL
500 mcg → 0.1 mL → 10 units
Draw to the 10-unit mark on your U-100 syringe. One vial lasts about 20 days at 1× per day.
Research use only — not medical advice. Store reconstituted vials refrigerated, 2–8 °C (36–46 °F). mg vs mcg: 1 mg = 1,000 mcg; mixing them up is a thousand-fold error. Always double-check the unit label and the decimal place before drawing.
Quick reference: common vials
Concentrations for the vial-and-water combinations people use most, plus the draw for a 500 mcg dose.
| Vial | BAC water | Concentration | 500 mcg dose | U-100 units |
|---|---|---|---|---|
| 5 mg | 1 mL | 5,000 mcg/mL | 0.100 mL | 10.0 |
| 5 mg | 2 mL | 2,500 mcg/mL | 0.200 mL | 20.0 |
| 10 mg | 2 mL | 5,000 mcg/mL | 0.100 mL | 10.0 |
| 10 mg | 3 mL | 3,333.333 mcg/mL | 0.150 mL | 15.0 |
| 20 mg | 4 mL | 5,000 mcg/mL | 0.100 mL | 10.0 |
| 20 mg | 8 mL | 2,500 mcg/mL | 0.200 mL | 20.0 |
| 30 mg | 3 mL | 10,000 mcg/mL | 0.050 mL | 5.0 |
| 30 mg | 6 mL | 5,000 mcg/mL | 0.100 mL | 10.0 |
How to reconstitute, step by step
- Let the vial and the bacteriostatic water come to the same temperature before you start.
- Wipe the vial stopper and the water vial top with an alcohol swab.
- Draw your chosen volume of bacteriostatic water and inject it slowly down the side of the peptide vial — don't blast the powder directly.
- Swirl gently until the powder dissolves. Don't shake — shaking can degrade peptides.
- Use the calculator above (or the quick-reference table) to work out your draw, and double-check the unit — mg and mcg differ a thousand-fold.
- Store the reconstituted vial in the refrigerator, 2–8 °C (36–46 °F), and use it within about a month, or whatever the vial label states. Cloudiness or particles after mixing means don't use it.
Common questions
How do I calculate units on an insulin syringe?
U-100 insulin syringes hold 100 units per 1 mL. Work out the concentration (vial amount in mcg divided by the mL of bacteriostatic water added), divide your dose in mcg by that concentration to get mL, then multiply by 100 to get units. The calculator above does exactly this.
How much bacteriostatic water should I add?
There is no single right amount — the water sets the concentration, and the dose stays the same either way. More water means a lower concentration and a larger, easier-to-measure draw; less water means a smaller, harder-to-measure draw. Common choices are 1–3 mL for a 5–10 mg vial.
How long does a reconstituted vial last?
Commonly given guidance is to store reconstituted vials refrigerated — 2–8 °C, that is 36–46 °F — and use them within about a month, following the vial label where it states one. The calculator shows how many days your dosing schedule takes to finish a vial.
Why does my dose look different from someone else's?
The same dose in mcg can require very different draw volumes depending on how much water was added. Always recalculate for your own vial and water amount rather than copying a units number — and double-check whether a figure is in mg or mcg, since mixing them up is a thousand-fold error.