Pharmaceutical-Grade BAC Water | Houston, TX | HPLC-Tested | COA Every Order
What Is Bacteriostatic Water?
Bacteriostatic water is sterile water containing 0.9% benzyl alcohol, a preservative that inhibits bacterial growth without killing existing bacteria. Unlike single-use sterile water for injection, bacteriostatic water is formulated for multi-dose use — allowing a single vial to be accessed multiple times over 28 days without contamination risk.
Why Is Benzyl Alcohol Used?
Benzyl alcohol at 0.9% concentration creates an inhospitable environment for bacterial growth. It acts as a bacteriostatic agent — it does not kill bacteria on contact, but prevents their reproduction and proliferation in the vial after the rubber stopper has been punctured. This is what makes bacteriostatic water the standard choice for peptide reconstitution protocols requiring repeated access to the same vial.
Bacteriostatic Water vs Sterile Water for Injection
The critical difference is multi-dose vs single-dose use. Sterile water for injection (SWFI) contains no preservative and must be used immediately after first entry — once opened, it cannot be safely accessed again. Bacteriostatic water’s benzyl alcohol preservative allows 28-day multi-draw use from the same vial. For most peptide research protocols requiring repeated reconstitution from the same vial, bacteriostatic water is the appropriate choice.
What Does USP-Grade Mean?
USP-grade means the product meets standards set by the United States Pharmacopeia — the official compendia defining quality, purity, and identity requirements for pharmaceutical ingredients and products. USP-grade bacteriostatic water must meet specifications for pH (4.5–7.0), benzyl alcohol concentration (0.9%), sterility, and pyrogen/endotoxin content. Renew Lab Group’s bacteriostatic water is USP-grade, manufactured under ISO-compliant cleanroom conditions in Houston, TX.
What Is the 28-Day Beyond-Use Date (BUD)?
The beyond-use date (BUD) of bacteriostatic water is 28 days after the first needle entry into the vial. After 28 days, even with the benzyl alcohol preservative, the vial should be discarded regardless of remaining volume. This timeframe is established by USP guidelines and represents the validated safety window for multi-dose preserved water products. Always date your vial on first use.
Frequently Asked Questions
Q: Can bacteriostatic water be used for any peptide?
A: Bacteriostatic water is compatible with most lyophilized peptides used in research. The benzyl alcohol concentration (0.9%) is well within the accepted range for most research applications. Always consult the specific peptide’s handling guidelines.
Q: How should bacteriostatic water be stored?
A: Store unopened vials at room temperature (59–86°F / 15–30°C) away from light. After first use, refrigerate at 36–46°F (2–8°C). Discard 28 days after first entry regardless of remaining volume.
Q: What is the difference between lot-level and batch-level HPLC testing?
A: Lot-level testing means one sample from a production run is tested to represent the entire lot. Batch-level testing means every individual manufactured batch is independently tested before release. Renew Lab Group uses batch-level HPLC testing — every batch, not just representative samples, is verified before it ships.
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Written by
Naomi Crabtree
Quality Assurance Specialist & Research Consultant · Renew Lab Group
Naomi specializes in pharmaceutical quality assurance, HPLC analysis, and USP compendial testing. She oversees Certificate of Analysis verification and research compliance for Renew Lab Group’s bacteriostatic water products.
