This peptide reconstitution calculator shows how many units to draw after mixing a peptide vial with bacteriostatic (BAC) water. Enter the amount on the vial label, the water you added, and your dose.
How to use the Peptide Reconstitution Calculator
- Enter the peptide in vial, or tap a preset.
- Enter the bac water added, or tap a preset.
- Enter the desired dose and choose mcg or mg.
- Choose the syringe type.
- Read the result card. It updates as you type, and you can copy or share it.
About this calculator
Lyophilized (freeze-dried) peptides arrive as a powder. Adding bacteriostatic (BAC) water dissolves the powder into a solution with a known concentration. Once you know the concentration, any dose can be converted to a volume and then to the unit markings on an insulin syringe.
Insulin syringe units measure volume, not drug amount. On a standard U-100 scale, 1 unit is 0.01 mL, so 100 units fill 1 mL. U-50 and U-30 syringes use the same scale with a smaller barrel, which makes small volumes easier to read.
Frequently asked questions
Does the amount of BAC water change my dose?
No. Water only changes the concentration. More water means each unit holds less peptide, so you draw more units for the same dose.
Why do my results show a fraction of a unit?
Most insulin syringes are marked in 1- or 2-unit steps. If the result lands between marks, round to the nearest line you can read, or change the water volume so the dose lands on a whole number.
Can I use sterile water instead of BAC water?
Sterile water has no preservative, so a multi-dose vial mixed with it is usually used immediately or within a short period. BAC water contains 0.9% benzyl alcohol, which slows bacterial growth for multi-dose use.
Sources
- ISO 8537: Sterile single-use syringes for insulin. International Organization for Standardization.
- General Chapter <797> Pharmaceutical Compounding: Sterile Preparations. U.S. Pharmacopeia.
- SI units and prefixes. National Institute of Standards and Technology.
Related calculators
- Reverse Reconstitution Calculator: This reverse reconstitution calculator works backward from a target syringe mark to tell you how much BAC water to add, so every dose lands on an easy-to-read line.
- Insulin Syringe Units Calculator: This insulin syringe units calculator converts any dose and concentration into the units and milliliters to draw, with a syringe diagram showing the fill line.
- Doses per Vial Calculator: This doses per vial calculator divides the amount in your vial by your dose to show how many full doses you get and what is left over.
- Peptide Concentration Calculator: This peptide concentration calculator shows how strong your solution is after reconstitution, in mg/mL, mcg/mL, and mcg per insulin syringe unit.
Medical disclaimer. This calculator is for educational purposes only and is not medical advice. Results are mathematical estimates based on the values you enter. Many peptides listed here are not approved by the FDA for human use. Confirm every dose with a licensed healthcare provider or your approved study protocol, and follow the product label.
