The peptide reconstitution calculator below works out the concentration of a reconstituted research peptide and the exact number of insulin-syringe units that correspond to a target amount — so your laboratory measurements are consistent from vial to vial. Enter the milligrams of peptide in the vial, the volume of bacteriostatic water you added, and the amount you want to measure.
Enter the peptide amount and water volume to see the concentration and syringe units.
Units are shown for a U-100 insulin syringe (1 mL = 100 units). For research reconstitution calculations only — see the disclaimer below.
How the calculation works
Reconstitution is simple arithmetic once you know two numbers: how much peptide is in the vial and how much liquid you dissolved it in.
- Concentration (mg/mL) = peptide (mg) ÷ bacteriostatic water (mL)
- Concentration (mcg/mL) = concentration (mg/mL) × 1000
- Volume to draw (mL) = target amount (mcg) ÷ concentration (mcg/mL)
- Insulin units (U-100) = volume to draw (mL) × 100 (because a U-100 syringe marks 100 units per 1 mL)
Worked example
Suppose a vial contains 10 mg of peptide and you add 2 mL of bacteriostatic water:
- Concentration = 10 ÷ 2 = 5 mg/mL (5,000 mcg/mL)
- To measure 250 mcg: 250 ÷ 5,000 = 0.05 mL = 5 units on a U-100 syringe
- Portions per vial: 10,000 mcg ÷ 250 mcg = 40
Reconstitution best practice
Add the bacteriostatic water slowly down the inside wall of the vial rather than directly onto the lyophilised pellet, and let it dissolve without shaking. For step-by-step technique see our peptide reconstitution guide, and for keeping reconstituted material stable see the peptide storage guide. Every peptide in the BioSequence Labs catalog ships with a lot-specific Certificate of Analysis so you know the identity and purity of what you are reconstituting.
Frequently asked questions
What is a peptide reconstitution calculator?
It converts a vial of lyophilised (freeze-dried) peptide and a chosen volume of bacteriostatic water into a concentration, then tells you how many insulin-syringe units correspond to a target amount in micrograms — removing manual arithmetic errors in the lab.
What does U-100 mean?
U-100 describes an insulin syringe calibrated so that 1 mL equals 100 units. It is the most common syringe used for measuring small liquid volumes; the calculator reports results in these units.
How much bacteriostatic water should I add?
Any volume works — more water simply makes a more dilute solution that is easier to measure in small amounts, while less water makes a concentrated solution. Enter your chosen volume and the calculator shows the resulting concentration.
Research Use Only. This calculator is provided solely for laboratory research calculations. BioSequence Labs products are sold strictly for in-vitro research and development and are not for human or animal consumption. Nothing here is medical, dosing, or clinical guidance.