Bacteriostatic Water: What It Is and Why It Matters

What Is Bacteriostatic Water?

Bacteriostatic water is sterile water containing 0.9% benzyl alcohol. The benzyl alcohol acts as a bacteriostatic preservative — it inhibits the growth of bacteria, allowing the water to be used multiple times from a single vial.

Bacteriostatic Water vs Sterile Water

The key difference is the preservative:

• Bacteriostatic water — contains 0.9% benzyl alcohol, which inhibits bacterial growth. Multi-use (up to 28 days after first use).
• Sterile water — no preservative. Single-use only; must be discarded after opening.

For peptide research, bacteriostatic water is preferred because:

• It allows multi-use from a single vial (more economical)
• It protects the reconstituted peptide solution from bacterial contamination
• It is the standard solvent for peptide reconstitution

How to Use Bacteriostatic Water

1. Swab the rubber stopper with an alcohol swab
2. Draw the desired volume using an insulin needle
3. Inject slowly into the peptide vial (down the side, not onto the powder)
4. Gently swirl to dissolve
5. Store the reconstituted solution refrigerated at 2–8°C

Storage

• Store bacteriostatic water at room temperature (15–25°C)
• Do not freeze
• Discard 28 days after first use
• Keep out of reach of children

Buying Bacteriostatic Water

HPLC Peps, the best peptide supplier UK, supplies bacteriostatic water in 10ml multi-use vials. It is intended for reconstitution of lyophilised research peptides in laboratory settings.

Research Use Only

Bacteriostatic water is for laboratory research use only. Not for human consumption, medical diagnosis, or treatment.