Peptide Reconstitution Calculator
Enter your vial size and BAC water volume to calculate solution concentration, exact draw volume in mL, and insulin syringe units. Results update instantly.
Enter your vial amount, how much BAC water you'll add, and the peptide amount in mcg. We'll tell you exactly how much to draw.
Printed on your vial label
Volume of diluent added
Research amount in micrograms
2.50 mg/mL
2500 mcg/mL
0.100 mL
100.0 µL
10.0 units
On a 100-unit insulin syringe
How to use this calculator
- 1Enter the total peptide content of your vial in milligrams (mg). This is the amount printed on the vial label, not the vial volume.
- 2Enter the volume of bacteriostatic water (BAC water) you will inject into the vial in milliliters (mL). This determines your final solution concentration.
- 3Select the peptide amount for your research protocol in micrograms (mcg).
- 4The calculator outputs the resulting concentration in mcg/mL, the exact draw volume in mL, and the corresponding graduation on a 100-unit insulin syringe.
- 5Switch to the Reverse tab if you know the syringe units already drawn and need to verify the resulting peptide amount.
Research Use Only
This tool is provided for in-vitro laboratory research planning only. All compounds sold by Pure Peptides are strictly for laboratory research use. This calculator does not constitute medical advice and must not be used to guide human administration of any substance.
Common reconstitution volumes
Reconstitution FAQs
What is bacteriostatic water and why is it used for reconstitution?
Bacteriostatic water (BAC water) is sterile water for injection containing 0.9% benzyl alcohol. The benzyl alcohol functions as a preservative by inhibiting microbial proliferation, which allows a reconstituted peptide solution to remain usable for up to 28 days when stored refrigerated at 2 to 8 degrees Celsius. It is the standard diluent for research peptide reconstitution and is compatible with virtually all lyophilized peptide compounds.
How do I reconstitute a lyophilized peptide vial?
Draw the required volume of BAC water into a syringe. Insert the needle through the rubber stopper and direct the stream slowly down the inside wall of the vial rather than squirting it directly onto the lyophilized cake. This minimizes foaming and mechanical stress on the peptide. Once all the solvent is in, gently swirl the vial until the powder fully dissolves. Do not shake. The resulting solution should be clear and colorless. If you see particulates or cloudiness, do not use the solution.
What does the syringe units reading mean?
A standard U-100 insulin syringe is graduated in units, where 100 units equals 1 mL. Each unit therefore equals 0.01 mL (10 microliters). The calculator converts your required draw volume in mL to the corresponding unit graduation on the syringe scale. This eliminates the need for manual conversion and reduces the risk of measurement error when working with small volumes.
How should I store a reconstituted peptide solution?
Store reconstituted solutions refrigerated at 2 to 8 degrees Celsius. At this temperature, benzyl alcohol-preserved solutions remain stable for up to 28 days. Do not freeze a reconstituted solution. Ice crystal formation during freezing can denature the peptide and compromise compound integrity. If your research timeline extends beyond 28 days, reconstitute only the volume needed for the immediate protocol and store the remaining lyophilized powder at -20 degrees Celsius for long-term stability.
What concentration should I target when reconstituting?
The optimal concentration depends on the compound and the volumes practical for your protocol. A common approach is to target a concentration where each individual research amount corresponds to a draw volume of 0.05 to 0.20 mL (5 to 20 units on a U-100 syringe). Volumes below 0.01 mL introduce significant measurement error; volumes above 0.5 mL per draw may be impractical for certain administration routes. Use the calculator to test different BAC water volumes and find the concentration that fits your protocol.
Can sterile water be substituted for bacteriostatic water?
Sterile water for injection can be used as a diluent but contains no preservative. A vial reconstituted with plain sterile water should be treated as a single-use preparation and used within 24 hours to minimize contamination risk. For any research protocol requiring multiple draws from the same vial over days or weeks, bacteriostatic water is the required diluent. Using sterile water in a multi-use context introduces unacceptable microbiological risk.
Does adding more BAC water change the total peptide content?
No. The total amount of peptide in the vial is fixed by the label weight and is independent of how much BAC water you add. Adding more BAC water produces a lower concentration solution; adding less produces a higher concentration solution. The peptide content does not change. The BAC water volume only determines the concentration of the resulting solution, which in turn affects the draw volume required for a given research amount.
What if my peptide does not fully dissolve?
Most lyophilized research peptides dissolve readily in BAC water. If you observe incomplete dissolution after gentle swirling, allow the vial to sit refrigerated for 15 to 30 minutes and swirl again. Peptides with high hydrophobic content may require initial dissolution in a small volume of dilute acetic acid (0.1% to 1% in water) or acetonitrile before diluting with BAC water to the target concentration. Check the compound-specific handling notes on the product COA or contact us if dissolution issues persist.
Need bacteriostatic water?
We stock pharmaceutical-grade bacteriostatic water in 30 mL multidose vials, shipped with cold-chain packaging as standard.
Shop Bacteriostatic Water