Free research tool
Peptide Reconstitution Calculator
Work out the concentration of a reconstituted research peptide and the volume to withdraw for a given amount. Enter the peptide mass in the vial, the bacteriostatic water you added, and your target amount per draw.
Inputs
Total mass of lyophilised peptide, from the label or COA.
Volume of solvent used to reconstitute the vial.
The amount of peptide you want in a single withdrawal.
Common vial sizes
Result
Volume to withdraw
0.05mL
5units · U-100 syringe
Concentration
5 mg/mL
5,000 mcg/mL
Draws per vial
≈ 40
at this amount
For laboratory research use only. This tool performs a volume/concentration calculation and is not dosing guidance, medical advice, or a recommendation of any amount. Always follow the guidance for your specific compound and your laboratory protocols.
How the calculation works
Reconstituting a lyophilised peptide is a two-step calculation. First, the concentration of the solution is the peptide mass divided by the volume of bacteriostatic water you added:
concentration (mg/mL) = peptide mass (mg) ÷ water volume (mL)
Then the volume to withdraw for a target amount is that amount divided by the concentration:
volume to draw (mL) = target amount ÷ concentration
For example, a 10 mg vial reconstituted with 2 mL of bacteriostatic water gives a concentration of 5 mg/mL (5,000 mcg/mL). To obtain 250 mcg you would withdraw 0.05 mL — which reads as 5 units on a U-100 insulin syringe (where 100 units = 1 mL).
Before you reconstitute
Research peptides ship as a lyophilised (freeze-dried) powder and are dissolved in the laboratory before use. Bacteriostatic water is the standard solvent. For the full handling process — adding the solvent gently, swirling rather than shaking, and storage — see our guides.
Frequently asked questions
- How does the peptide reconstitution calculator work?
- It divides the peptide mass in the vial by the volume of bacteriostatic water added to give the solution concentration (mg/mL and mcg/mL), then divides your target amount per draw by that concentration to give the volume to withdraw — shown in millilitres and in units on a standard U-100 insulin syringe.
- What is the formula for reconstituting a peptide?
- Concentration = peptide mass (mg) ÷ water volume (mL). Volume to draw = target amount ÷ concentration. For example, 10 mg reconstituted in 2 mL gives 5 mg/mL (5000 mcg/mL); to obtain 250 mcg you withdraw 0.05 mL, which is 5 units on a U-100 syringe.
- Why are draw volumes shown in insulin syringe units?
- A U-100 insulin syringe is the standard fine-measurement tool in the laboratory, where 100 units equals 1 mL. Showing units alongside millilitres makes a small volume easier to measure accurately.
- What water should I use to reconstitute a research peptide?
- Bacteriostatic water — sterile water containing 0.9% benzyl alcohol — is the standard solvent for reconstituting lyophilised research peptides in the laboratory.
For laboratory research use only. Not for human or veterinary use, consumption, or therapeutic application. This calculator is general information for researchers, not medical advice or dosing guidance.