How does the peptide reconstitution calculator work?

It divides the peptide mass in the vial by the volume of solvent added to give the solution concentration (mg/mL and mcg/mL), then divides your target aliquot mass by that concentration to give the volume to aliquot — shown in millilitres and on a 100-graduation (0.01 mL) scale.

What is the formula for reconstituting a peptide?

Concentration = peptide mass (mg) ÷ solvent volume (mL). Volume to aliquot = target aliquot mass ÷ concentration. For example, 10 mg reconstituted in 2 mL gives 5 mg/mL (5000 mcg/mL); to obtain a 250 mcg aliquot you measure 0.05 mL, which is 5 graduations on a 0.01 mL scale.

Why are volumes shown on a 100-graduation scale?

A 100-graduation scale (where 100 graduations equal 1 mL, or 0.01 mL per graduation) is a convenient fine-measurement reference in the laboratory. Showing graduations alongside millilitres makes a small volume easier to measure accurately.

What solvent 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.

Free research tool

Peptide Reconstitution Calculator

Work out the concentration of a reconstituted research peptide and the volume to aliquot for a given mass. Enter the peptide mass in the vial, the solvent volume you added, and your target aliquot mass.

Inputs

Peptide in vial

Total mass of lyophilised peptide, from the label or COA.

Bacteriostatic water added

Volume of solvent used to reconstitute the vial.

Target aliquot mass

The mass of peptide contained in a single aliquot of solution.

Common vial sizes

Result

Volume to aliquot

0.05mL

5graduations · 0.01 mL scale

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 aliquot for a target mass is that mass divided by the concentration:

volume to aliquot (mL) = target aliquot mass ÷ 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 a 250 mcg aliquot you would measure 0.05 mL — which reads as 5 graduations on a 0.01 mL scale (where 100 graduations = 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.

How to reconstitute peptides View bacteriostatic water

Frequently asked questions

How does the peptide reconstitution calculator work?: It divides the peptide mass in the vial by the volume of solvent added to give the solution concentration (mg/mL and mcg/mL), then divides your target aliquot mass by that concentration to give the volume to aliquot — shown in millilitres and on a 100-graduation (0.01 mL) scale.
What is the formula for reconstituting a peptide?: Concentration = peptide mass (mg) ÷ solvent volume (mL). Volume to aliquot = target aliquot mass ÷ concentration. For example, 10 mg reconstituted in 2 mL gives 5 mg/mL (5000 mcg/mL); to obtain a 250 mcg aliquot you measure 0.05 mL, which is 5 graduations on a 0.01 mL scale.
Why are volumes shown on a 100-graduation scale?: A 100-graduation scale (where 100 graduations equal 1 mL, or 0.01 mL per graduation) is a convenient fine-measurement reference in the laboratory. Showing graduations alongside millilitres makes a small volume easier to measure accurately.
What solvent 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.