BAC Water 101: What Bacteriostatic Water Is and Why We Use It

Bacteriostatic water is one of the most commonly used items in any peptide research setup, but it is often misunderstood. Here is a straightforward explanation of what it is and why it matters.

What Makes It Different From Sterile Water

Bacteriostatic water is sterile water for injection that contains 0.9% benzyl alcohol as a preservative. This addition inhibits bacterial growth, which allows a single vial to be used for multiple withdrawals over a period of time without the same contamination risk as plain sterile water.

Why It Matters for Reconstitution

When reconstituting a lyophilised peptide, the diluent you use affects both stability and usable shelf life once the vial is open. Bacteriostatic water is the standard choice for multi-use vials in a research context precisely because of its preservative content.

Handling Notes

Allow the vial to reach room temperature before use, and always use a fresh sterile needle when withdrawing to avoid introducing contamination into the stock vial.

For laboratory research use only. Not intended for human use.