What Is Bacteriostatic Water?
Bacteriostatic water (BAC water) is sterile water containing 0.9% benzyl alcohol as a preservative. The benzyl alcohol inhibits bacterial growth, allowing the water to be used for multiple reconstitutions without the contamination risk of plain sterile water.
BAC Water vs. Sterile Water
Sterile water for injection contains no preservative — once punctured, it must be used immediately. Bacteriostatic water can be stored and reused for up to 28 days after first puncture, making it far more practical for research settings.
Proper Handling
Store unopened at room temperature (20-25°C). After opening, use within 28 days. Always use a new sterile needle for each withdrawal and swab the septum with isopropyl alcohol before puncturing.
Reconstituting Peptides
Draw the desired volume and inject slowly down the inside wall of the peptide vial — not directly onto the powder. Gently tilt and roll to dissolve. Never shake or vortex, as the air-liquid interface can denature peptides.
Calculating Volume
For a 5mg vial: adding 2.5mL yields 2mg/mL concentration. Adding 1mL yields 5mg/mL. Lower concentrations make small measurements easier; higher concentrations preserve peptide integrity over time.
Storage After Reconstitution
Reconstituted peptides should be refrigerated at 2-8°C. Most maintain acceptable purity for 3-4 weeks. Never freeze reconstituted solutions unless the specific peptide tolerates freeze-thaw cycles.
