Written by the AllMyPeptides Research Team
What Is Bacteriostatic Water?
Bacteriostatic water is sterile water that contains 0.9% benzyl alcohol as a bacteriostatic preservative. The benzyl alcohol prevents the growth of bacteria and fungi, making it the preferred solvent for reconstituting research peptides that will be used over multiple doses.
The term bacteriostatic means bacteria-static — it inhibits bacterial growth without necessarily killing existing bacteria. This is achieved through the benzyl alcohol, which disrupts bacterial cell membrane integrity and prevents replication.
AllMyPeptides supplies bacteriostatic water in 10ml and 30ml vials, sterile and ready for use in peptide reconstitution.
Bacteriostatic Water vs Sterile Water
The key difference is the preservative:
- Bacteriostatic water: Contains 0.9% benzyl alcohol. Prevents bacterial growth for up to 28 days after first penetration. Ideal for multi-dose research applications.
- Sterile water: No preservative. Must be used immediately after opening. Not suitable for research protocols requiring multiple withdrawals from the same vial.
For peptide research, bacteriostatic water is strongly recommended because reconstituted peptides are typically stored for several days to weeks, during which sterile water could support bacterial growth.
Why Not Use Tap Water or Distilled Water?
Tap water and distilled water are never appropriate for peptide reconstitution:
- Tap water: Contains chlorine, minerals, and potential bacterial contaminants that will degrade peptides and compromise research.
- Distilled water: While free of minerals, it lacks a preservative and is not sterile. Bacterial growth will occur.
- Both: Have an improper pH for peptide stability and may contain pyrogens that interfere with research.
Only use sterile bacteriostatic water specifically labelled for injection/reconstitution purposes.
How to Use Bacteriostatic Water
Follow these steps when reconstituting peptides with bacteriostatic water:
- Clean both vial stoppers with alcohol prep pads
- Draw air into the syringe equal to the water volume you will add
- Inject the air into the bacteriostatic water vial
- Withdraw the desired volume slowly
- Inject the water slowly down the inside wall of the peptide vial
- Allow the water to dissolve the powder naturally — do not shake
Store reconstituted peptides at 2-8°C and use within 30 days. The benzyl alcohol in the bacteriostatic water helps prevent bacterial growth during this storage period.
Storage and Shelf Life
Unopened bacteriostatic water has a shelf life of approximately 1-2 years when stored at room temperature, protected from light. Once the vial stopper has been pierced:
- Use within 28 days
- Store at room temperature or refrigerated
- Do not freeze
- Keep away from direct light
Discard any bacteriostatic water that appears cloudy, discoloured, or contains visible particles.
Frequently Asked Questions
Why is benzyl alcohol used in bacteriostatic water?+
Can I use bacteriostatic water for all peptides?+
How long does reconstituted peptide last with bacteriostatic water?+
Is bacteriostatic water the same as normal saline?+
Related Guides
Products discussed in this guide are for research and laboratory use only. AllMyPeptides does not condone or support misuse of any research materials. Not for human or animal consumption.