Bacteriostatic Water (BW) is sterile water containing 0.9% benzyl alcohol (v/v) as a preservative. The benzyl alcohol disrupts bacterial cell membrane integrity, providing sustained antimicrobial protection that allows multi-use vials to remain sterile across multiple punctures — typically 28–30 days. This is the critical distinction from sterile water for injection (SWFI): SWFI is single-use only; BW permits multiple draws from the same vial, essential for multi-week research protocols where a single vial is accessed repeatedly. Benzyl alcohol has no significant pharmacological activity at 0.9% concentration in research applications.
Research Applications
Peptide Reconstitution
Primary diluent for all lyophilized research peptides — enables multi-use vial stability
Hormone Reconstitution
HGH, HCG, HMG, and other protein hormones requiring multi-dose stability
Multi-Week Protocols
28–30 day preserved stability allows single vial to span full research protocol
Volume Calculation
Dilution standard for precise peptide concentration calculation
Storage Compatibility
Neutral pH compatible with most lyophilized peptide compounds
Quick Specs
Form
Sterile aqueous solution
Preservative
0.9% Benzyl Alcohol (v/v)
pH
4.5–7.0
Use
Multi-use vial (28–30 day stability after first puncture)
Why use Bacteriostatic Water instead of sterile water?
Bacteriostatic Water contains 0.9% benzyl alcohol, which inhibits bacterial growth and allows the same vial to be used across multiple injections (28–30 days). Sterile water for injection (SWFI) has no preservative and must be discarded after single use. For multi-week research protocols requiring daily or multiple-weekly dosing from the same vial, BW is the correct choice.
How much Bacteriostatic Water should I use to reconstitute peptides?
This depends on the desired concentration. Common approach: for a 10mg vial, adding 2mL BW gives 5mg/mL (5000mcg/mL), so 0.1mL on an insulin syringe = 500mcg. Use QSC’s free reconstitution calculator at qscpeptide.com/ultimate-peptide-calculators-mixing-tools/ to calculate exact volumes.
How long does Bacteriostatic Water last after opening?
Once the vial seal is first punctured, Bacteriostatic Water is stable for 28–30 days due to benzyl alcohol preservative. Store at room temperature or 2–8°C, away from direct sunlight. Discard after 30 days from first puncture.
Research Use Only: All QSC compounds are sold strictly for laboratory research purposes only. Not for human consumption, veterinary use, or any other application. Researchers are responsible for compliance with local regulations.
QSC Network
Compound reference, COA verification, and regional warehouse information across the QSC network.
