About Bacteriostatic Water
Bacteriostatic Water for Injection (BAC Water) is sterile water that contains 0.9% benzyl alcohol as a preservative. Unlike plain sterile water for injection — which is intended for a single use and must be discarded after one puncture — the benzyl alcohol in BAC water inhibits bacterial growth, allowing a single 10mL vial to be safely punctured and used multiple times over the course of several weeks.
In a research setting, BAC water is the standard diluent used to reconstitute lyophilized (freeze-dried) peptides into a liquid solution suitable for precise volumetric dosing with an insulin syringe. Each 10mL multi-use vial is manufactured to USP standards and is sterile-filtered and sealed under aseptic conditions. Because almost every lyophilized peptide vial requires reconstitution before use, BAC water is one of the most frequently re-ordered items for any research peptide protocol.
Why Bacteriostatic Water?
Lyophilized peptides are freeze-dried to maximize shelf stability during storage and shipping, but must be returned to a liquid state before they can be measured and administered with a syringe. Bacteriostatic water is preferred over plain sterile water for this purpose because its benzyl alcohol content allows the same vial to be reused across an entire research protocol, rather than requiring a fresh single-use vial of sterile water for every reconstitution.