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How to Reconstitute Peptides
Step-by-step guide to mixing bacteriostatic water, calculating concentrations, and storing reconstituted solutions.
What You Need
To reconstitute a lyophilised peptide the following is required: (1) the peptide vial (lyophilised powder), (2) bacteriostatic water (BAC water — sterile water containing 0.9% benzyl alcohol), (3) sterile laboratory transfer equipment, and (4) alcohol swabs. Bacteriostatic water is the standard reconstitution solvent because the benzyl alcohol inhibits bacterial growth, allowing the reconstituted solution to be stored for multiple uses over 28+ days.
Step-by-Step Reconstitution
Standard laboratory reconstitution procedure: (1) Wipe both vial stoppers (peptide and BAC water) with alcohol swabs. (2) Using sterile laboratory equipment, measure the desired volume of BAC water (typically 1–2mL). (3) Transfer the water into the peptide vial through the rubber stopper. (4) SLOWLY add the water down the side of the vial — do not direct it onto the powder. (5) Gently swirl the vial until the powder is fully dissolved. NEVER shake the vial — shaking can denature the peptide and destroy its biological activity. (6) Once dissolved, the solution should be clear. If cloudy or particulate, discard and reconstitute a new vial.
Calculating Concentration
If 2mL of BAC water is added to a 5mg peptide vial, the concentration is 5mg / 2mL = 2.5mg per mL = 2,500mcg per mL. A reconstitution calculator is available at /tools/reconstitution for automatic concentration calculation.
Storage After Reconstitution
Once reconstituted, store the vial upright in the refrigerator (2–8°C). Do not freeze reconstituted peptide — freeze-thaw cycles degrade most peptides irreversibly. With bacteriostatic water, most peptides remain stable for 28–42 days when refrigerated. Always label the vial with the reconstitution date and discard after the recommended period. Use our Storage Calculator at /tools/storage for peptide-specific shelf life data.
Common Mistakes to Avoid
(1) Spraying water directly onto the powder — this creates foam and can denature the peptide. Always run the water down the glass wall. (2) Shaking the vial — swirl gently only. (3) Using sterile water instead of BAC water for multi-use — sterile water has no preservative, so bacterial contamination is a risk after the stopper is first punctured. (4) Storing at room temperature — reconstituted peptides degrade rapidly above 8°C. (5) Reusing laboratory equipment — always use fresh sterile equipment for each transfer.
Research Disclaimer: All content on this page is provided for educational and informational purposes only and relates strictly to published preclinical research. Silver Peptide products are supplied for in vitro laboratory research use only. They are not approved by the MHRA, FDA, or any regulatory body for human consumption, injection, or veterinary use. They are not medicines and must not be used as such. Nothing on this page constitutes medical advice.