This article is for educational and research purposes only. Nothing here constitutes medical advice. Consult a licensed healthcare provider before using any injectable compound.
What Is Bacteriostatic Water?
Bacteriostatic water (commonly called "bac water") is sterile water that contains 0.9% benzyl alcohol as a preservative. The benzyl alcohol inhibits the growth of bacteria and other microorganisms, making the water safe for multiple uses from the same vial. This is distinct from sterile water for injection, which contains no preservative and is intended for single-use only.
Why Bacteriostatic Water Instead of Sterile Water?
The key advantage is multi-use safety. When you reconstitute a peptide, you will typically draw from the vial multiple times over days or weeks. Each time a needle penetrates the vial stopper, there is a small risk of introducing bacteria. The benzyl alcohol in bac water prevents those bacteria from multiplying, keeping the solution safe throughout its shelf life.
Sterile water has no preservative. Once the seal is broken, it becomes vulnerable to microbial contamination. Using sterile water to reconstitute a peptide that will be used over multiple days increases infection risk significantly.
How to Use Bac Water for Reconstitution
- Step 1: Clean the tops of both the bac water vial and the peptide vial with alcohol swabs.
- Step 2: Draw the desired amount of bac water into a syringe. The amount depends on your dosing needs — common volumes are 1-2 mL per vial.
- Step 3: Insert the needle into the peptide vial at an angle, letting the water run down the inside wall of the vial rather than blasting directly onto the lyophilized powder.
- Step 4: Gently swirl the vial to dissolve the peptide. Never shake vigorously — shaking can damage the peptide structure and cause aggregation.
- Step 5: Wait until the powder is fully dissolved and the solution is clear. If the solution remains cloudy after gentle swirling, something may be wrong.
Storage and Shelf Life
Unopened bacteriostatic water has a shelf life listed on the packaging, typically 1-2 years. Once opened, use within 28 days according to most manufacturer guidelines. Store at room temperature — bac water does not need refrigeration before use, though some people refrigerate it out of habit. After reconstituting a peptide, the mixed solution should be refrigerated at 2-8°C.
Where to Get Bacteriostatic Water
Bacteriostatic water is available from pharmacies (often without a prescription), medical supply companies, and online retailers. Look for USP-grade bacteriostatic water in pre-sterilized, sealed vials. Avoid bulk or unbranded options with unclear sourcing. Common vial sizes are 10 mL and 30 mL.