What Is Bacteriostatic Water and Why Peptides Use It
Bacteriostatic water, sterile water and saline are not interchangeable.
By PX1 Research Team · August 4, 2026
What Is Bacteriostatic Water and Why Peptides Use It
Definition
Bacteriostatic water is sterile water containing 0.9% benzyl alcohol as a preservative, which inhibits bacterial growth and enables multi-dose vial use for up to 28 days.
Versus sterile water
Sterile water has no preservative — a vial reconstituted with it is single-use. Saline contains sodium chloride and can affect certain peptide solubility profiles.
The 28-day rule
The benzyl alcohol preservative system is validated for 28 days of in-use time under refrigeration. Label the vial with the reconstitution date.
How PX1 documents every lot
Every PX1 lot ships with HPLC purity, LC-MS identity, residual solvent, moisture (Karl Fischer), sterility and endotoxin data. Lot documentation is published at /purity-reports, /endotoxin-reports and /coa. Synthesis, purification, lyophilization and vial fill happen in U.S. facilities — see /manufacturing-process.
Research use only. PX1 Research supplies compounds for laboratory and in-vitro research. Nothing here is medical advice, a dosing recommendation, or an offer for human or veterinary use. Figures cited are reported from published laboratory literature.