Bacteriostatic water: what it is and why research vials need it

What it contains

Bacteriostatic water is purified water containing 0.9% benzyl alcohol as a bacteriostatic preservative. The benzyl alcohol inhibits bacterial growth, which is what allows a reconstituted vial to be entered more than once over a period of days or weeks.

Sterile water, by contrast, contains no preservative and is intended for single-use preparations only.

Why it matters for peptide research

A reconstituted peptide vial that will be sampled repeatedly is exposed to the environment each time the stopper is pierced. Without a bacteriostatic agent, contamination risk rises with every entry and the solution's usable window shortens sharply.

• Use bacteriostatic water for multi-use research vials
• Use sterile water for single-use preparations
• Swab the stopper with alcohol before every entry
• Refrigerate reconstituted solutions at 2–8°C

Buying in the UK: what to expect from UK Peptide

Every vial is held in UK stock at -20°C in our Central London facility, so there are no customs delays, no overseas drop-shipping and no month-long waits. Orders placed before 2pm Monday to Friday are dispatched the same working day.

Express overnight delivery is £9.99 nationwide and free on orders over £200. Parcels are vacuum-sealed, gel-cooled, insulated and discreet.

• 99%+ minimum purity by HPLC, identity confirmed by mass spectrometry
• Independent third-party UK laboratory testing — never in-house self-certification
• Visa & Mastercard accepted (no American Express)
• Research use only — not for human or veterinary use. Purchasers must be 18+

Frequently asked questions

What is bacteriostatic water used for?

It is the standard diluent for reconstituting multi-use research peptide vials; the 0.9% benzyl alcohol inhibits bacterial growth between entries.

How much is bacteriostatic water in the UK?

£4.99 for a 3ml vial, dispatched same day with your peptide order from Central London.