The Core Difference

The key distinction is the preservative. Bacteriostatic water contains 0.9% benzyl alcohol, which inhibits bacterial growth and permits multi-dose use. Sterile water for injection contains no preservative and is intended for single-dose use.

When to Use Each

  • Bacteriostatic water: multi-dose reconstitution where you will draw from the vial multiple times.
  • Sterile water: single-use applications or where a preservative could interfere with your experiment.

Important Considerations

Always check that the preservative will not interact with your compound. For sensitive compounds, preservative-free sterile water may be the safer choice.