§ Glossary · lab supply

Bacteriostatic water

Sterile water containing 0.9% benzyl alcohol as a bacteriostatic preservative.

Bacteriostatic water for injection (BWFI) is sterile water containing 0.9% benzyl alcohol (a bacteriostatic agent that inhibits bacterial growth without killing existing bacteria). It's the standard diluent for reconstituting research peptides because it permits multi-dose drawdown over time without risk of microbial contamination from repeated needle entry. Once mixed, BWFI-reconstituted peptide solutions are typically stable refrigerated for ~4 weeks. Sterile water (without benzyl alcohol) is single-use only.

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