Reconstitution water, also called bacteriostatic water, is sterile water containing 0.9% benzyl alcohol as a preservative. It is the standard solvent used to reconstitute lyophilized (freeze-dried) peptide and protein research compounds into solution form. The benzyl alcohol acts as a bacteriostatic agent, inhibiting microbial growth and extending the usable life of reconstituted solutions. It is supplied in a sealed, sterile vial for laboratory use.

Bacteriostatic water is widely used across research and pharmaceutical settings as the standard reconstitution solvent for lyophilized compounds. Its role in research is primarily as a laboratory reagent rather than an active compound. Studies have validated benzyl alcohol at 0.9% concentration as effective for microbial growth inhibition while maintaining compatibility with peptide stability. It is referenced in USP standards for sterile preparations.

Reconstitution water should be stored at controlled room temperature (20-25°C / 68-77°F) in its original sealed vial, protected from light. Once opened, it should be used within 28 days. Avoid freezing. Always use sterile technique when accessing the vial — swab the septum with an alcohol wipe before each needle insertion. Discard if the solution appears cloudy or contains particulate matter.

All products from Peptide.co undergo rigorous third-party laboratory testing to verify identity and purity. Certificates of Analysis (COAs) are available at coa.peptide.co as batches are tested. Testing includes HPLC purity analysis, mass spectrometry identity confirmation, heavy metals screening, and microbial limits testing. All products are manufactured in FDA-registered facilities in the United States.

Bacteriostatic water contains 0.9% benzyl alcohol as a preservative, which inhibits microbial growth. Sterile water for injection (SWFI) contains no preservative and is intended for single-use only. For reconstituting lyophilized peptides in a research setting, bacteriostatic water is preferred because it allows multiple withdrawals from the same vial over up to 28 days while maintaining sterility. Sterile water must be discarded after a single use as it has no antimicrobial protection.

The volume of bacteriostatic water used for reconstitution depends on the peptide quantity and the desired concentration. Common reconstitution volumes range from 1 mL to 3 mL per vial. For precise calculations based on your specific compound and desired concentration, use the free Peptide Reconstitution Calculator available on Peptide.co. When adding water to the vial, direct the stream gently along the inside wall — do not spray directly onto the lyophilized powder.