Peptide Reconstitution Calculator
Enter how much compound is in the vial and how much diluent you added. The calculator returns the resulting concentration, the volume containing a given quantity of compound, and the equivalent graduations on a U-100 syringe — the arithmetic every lab does by hand when working with lyophilized material.
1 What is in the vial
2 What you want to draw
3 Work backwards optional
Choose the result you want and this tells you how much diluent to add to the vial in step 1.
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Insulin syringes are marked in units: on U-100, 100 units = 1 mL (1 unit = 0.01 mL); on U-40, 40 units = 1 mL (1 unit = 0.025 mL). These are arithmetic conversions for laboratory measurement planning only — not guidance for administration of any kind.
How the arithmetic works
Reconstitution is a dilution problem. A vial holding 10 mg of compound reconstituted with 2 mL of diluent gives 5 mg/mL, or 5000 mcg/mL. To obtain 250 mcg you withdraw 250 ÷ 5000 = 0.05 mL, which is 5 graduations on a U-100 syringe.
The only figure that changes the result is diluent volume: vial mass is fixed, so more diluent gives lower concentration and a larger withdrawal volume for the same quantity. Labs often pick a diluent volume that lands the working volume in an easily measured range rather than an awkward fraction of a graduation.
Practical notes
- Add diluent slowly down the vial wall and swirl — never shake. Foaming causes aggregation and reduces intact peptide.
- Bacteriostatic water (0.9% benzyl alcohol) suits stocks drawn from more than once; sterile water is for single-session preparations.
- Refrigerate reconstituted solutions at 2–8 °C and label aliquots with the lot number so results stay traceable to that batch’s certificate of analysis.
- Poorly soluble sequences may need a small volume of secondary solvent before aqueous dilution — consult solubility data for the specific peptide.
This tool performs unit conversions for laboratory measurement planning. It is not guidance for administration to humans or animals.