Peptide Reconstitution Calculator
Enter the vial mass, the volume of bacteriostatic water added, and the target amount per administration in your research protocol — the calculator returns the solution concentration, the exact volume to draw (in mL and U-100 insulin syringe units), and the number of doses per vial. All arithmetic follows standard laboratory concentration math: concentration = mass ÷ volume.
For laboratory research calculations only. Verify all arithmetic independently — vial contents include water and counterions, so exact quantitative work applies the net peptide content correction from the batch certificate of analysis.
How the Math Works
Every output derives from four identities of dilution arithmetic. Nothing here is peptide-specific — the same math applies to any mass dissolved in any solvent.
- Concentration
- concentration (mcg/mL) = vial mass (mg) × 1,000 ÷ diluent volume (mL)
- Draw volume per dose
- draw (mL) = target amount (mcg) ÷ concentration (mcg/mL)
- Syringe units (U-100)
- units = draw (mL) × 100
- Doses per vial
- doses = vial mass (mcg) ÷ target amount (mcg)
"Target syringe units" mode runs the same identities in reverse, solving the diluent volume that makes one dose land on a chosen syringe marking: diluent (mL) = vial mass (mcg) × target draw (mL) ÷ target amount (mcg).
Worked Example
A 5 mg vial reconstituted with 2 mL of bacteriostatic water yields a concentration of 5,000 mcg ÷ 2 mL = 2,500 mcg/mL. For a target amount of 250 mcg, the draw volume is 250 ÷ 2,500 = 0.1 mL, which is 10 units on a U-100 syringe, and the vial contains 5,000 ÷ 250 = 20 doses.
Open this example pre-filled in the calculator — every calculation produces a shareable link with the values encoded in the URL.
Frequently Asked Questions
How do you calculate peptide concentration after reconstitution?
Concentration is vial mass divided by diluent volume. A 5 mg vial reconstituted with 2 mL of bacteriostatic water gives 2.5 mg/mL, or 2,500 mcg/mL. The arithmetic assumes the labeled mass is entirely peptide; vial contents also include water and counterions, so exact quantitative work applies a net peptide content correction from the batch certificate of analysis.
What are 'units' on an insulin syringe?
Standard U-100 insulin syringes are graduated so that 100 units equal 1 mL — one unit is 0.01 mL (10 microliters). A 2,500 mcg/mL solution therefore contains 25 mcg per unit, and a 250 mcg amount corresponds to a 10-unit draw. The calculator converts between mL and units automatically.
How much bacteriostatic water should be added to a vial?
There is no single correct volume — it is chosen so the resulting draw per dose is practical to measure. Draws under about 5 units are difficult to read accurately on a U-100 syringe, while volumes above ~3 mL exceed a standard research vial. The calculator's 'Target syringe units' mode solves the diluent volume directly: enter the vial mass, the target amount per dose, and the desired draw size, and it returns the water volume to add.
Is this calculator medical or dosing advice?
No. It performs concentration arithmetic for laboratory research solutions and nothing else. It does not recommend amounts, routes, or schedules, and it is not guidance for human or veterinary use. All outputs should be verified independently before use in any experimental protocol.
Related Guides
- Peptide Reconstitution, Storage & Stability — solvent selection, technique, and degradation pathways
- Research Peptide Safety — evidence tiers and class-level safety patterns
- How to Evaluate Research Peptide Suppliers — reading COAs and the net peptide content correction
This calculator performs concentration arithmetic for laboratory research solutions. It is provided for educational purposes only, is not medical advice, and is not guidance for human or veterinary use. See the disclaimer for details.