Straight answers to the questions people ask most about bac water.
Short, sourced answers to the questions we hear most about bacteriostatic water. Each one links to a full guide if you want the detail behind it: start with what bacteriostatic water is, see how long it lasts, or compare it with sterile water.
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Bacteriostatic water is sterile water that contains 0.9% benzyl alcohol (9 mg per mL) as a preservative. The preservative stops bacteria from multiplying between withdrawals, so a single vial can be used repeatedly.
Two ingredients: sterile, nonpyrogenic water for injection and benzyl alcohol at 0.9%. It contains no salt and no other additives.
Yes, it contains benzyl alcohol, an aromatic alcohol used as a preservative. It is not the same as ethanol, the alcohol in drinks or hand sanitizer.
No. Sterile water contains no preservative and is intended for single use. Bacteriostatic water contains benzyl alcohol, so the same vial can be entered repeatedly for up to 28 days.
No. Normal saline is 0.9% sodium chloride with no preservative. Bacteriostatic water contains no salt. Bacteriostatic sodium chloride is a separate product that contains both salt and benzyl alcohol.
No. The FDA label lists storage at 20 to 25 °C (68 to 77 °F). Keeping an opened vial in the refrigerator is fine, but it does not extend the 28-day limit.
Up to 28 days after the first puncture of the stopper, which is the USP standard for multiple-dose containers unless the manufacturer states otherwise.
Yes. Unopened vials are good until the expiration date printed on the label. After that, sterility and preservative strength are no longer guaranteed.
No. Freezing can crack the vial and damage the stopper seal.
Pharmaceutical Bacteriostatic Water for Injection is an FDA-regulated drug product with a National Drug Code and is dispensed on prescription, which is why many pharmacies will not sell it over the counter.
No. It requires sterile, pyrogen-free water and a precisely measured preservative prepared under controlled conditions, with sterility testing that is not possible at home.
The per-vial price drops automatically in the cart: 1 to 2 vials at $10.99, 3 to 4 at $9.66, 5 to 9 at $8.80, and 10 or more at $8.00 each.
Within the United States only. Orders of $35 or more ship free.