What is bacteriostatic water?
Bacteriostatic water ("BAC water") is sterile, non-pyrogenic water for reconstitution to which 0.9% benzyl alcohol has been added as a preservative. The benzyl alcohol inhibits bacterial growth, so a single vial can be punctured repeatedly — the reason it is the standard diluent for lyophilised research peptides that are reconstituted once and drawn from over several weeks.
Plain sterile water has no preservative and is intended for single use only; once a sterile-water vial is opened it should be discarded. For multi-dose research work, bacteriostatic water is the correct choice for almost every peptide in the ClaraScience range. The exceptions are a small group of hydrophobic peptides that dissolve poorly at neutral pH — for those, start with acetic acid water.
ClaraScience bacteriostatic water is USP-grade, supplied in 10mL multi-dose vials with a Certificate of Analysis. For laboratory research use only.
Composition. Sterile water for reconstitution + 0.9% w/v benzyl alcohol (bacteriostatic preservative).
Use. Reconstituting lyophilised peptides; multi-dose withdrawals for up to 28 days after first puncture.
Not for. Peptides that precipitate at neutral pH — reconstitute those in acetic acid water first, then top up.
How to reconstitute a peptide with bacteriostatic water
1. Work clean. Wipe both vial stoppers with an alcohol swab and allow them to dry. Draw the required volume of bacteriostatic water into a sterile syringe — use the reconstitution calculator to pick a volume that gives a convenient concentration (1–2mL is typical for a 5–10mg vial).
2. Add slowly. Insert the needle through the peptide-vial stopper and let the water run down the inside wall of the vial rather than jetting it onto the lyophilised cake. Peptides are fragile; do not shake.
3. Swirl and wait. Gently swirl or roll the vial until the solution is clear. Most peptides dissolve within a minute; a faint haze that clears on standing is normal. Persistent cloudiness or particulates usually mean a hydrophobic peptide — see acetic acid water.
4. Store. Label the vial with the date of reconstitution and refrigerate at 2–8°C. Discard 28 days after the first puncture of the bacteriostatic-water vial, regardless of remaining volume. Full method: Reconstitution Guide.
Reference United States Pharmacopeia, General Chapter <797> Pharmaceutical Compounding — Sterile Preparations (beyond-use dating for multiple-dose containers: 28 days after initial entry unless otherwise specified).
Specifications
| Product |
Bacteriostatic Water 10mL |
| Composition |
Sterile water for reconstitution, 0.9% w/v benzyl alcohol (C₇H₈O, 108.14 g/mol) |
| Grade |
USP, sterile, non-pyrogenic |
| Vial |
10mL clear glass multi-dose vial, rubber stopper, flip-off cap |
| pH |
4.5–7.0 (typical) |
| Beyond-use |
28 days after first puncture (USP <797>) |
| Storage |
Room temperature (15–30°C); do not freeze |
| Compatibility |
All ClaraScience water-soluble peptides; use acetic acid water first for hydrophobic peptides |
Storage & Handling
- Unopened vial: room temperature, 15–30°C, protected from light. Do not freeze.
- After first puncture: swab the stopper before every entry and discard the vial 28 days after first use.
- Reconstituted peptides: 2–8°C, use within 28 days; avoid freeze-thaw. Volumes and concentrations: reconstitution calculator.
Full protocols: Storage & Handling Guide · Reconstitution Guide.
Ordering & Pricing — Australia
| Quantity |
Price per unit |
Saving |
| 1–4 units |
$14.95 AUD |
— |
| 5–9 units |
$12.95 AUD |
Save 13% |
| 10+ units |
$10.95 AUD |
Save 27% |
Free priority tracked shipping on orders over $250 AUD. Ships from our Australian warehouse; orders placed before 2pm AEST dispatch same business day. Wholesale enquiries welcome.
Frequently Asked Questions
Bacteriostatic water vs sterile water — which do I need?
Bacteriostatic water contains 0.9% benzyl alcohol so a vial can be entered repeatedly for up to 28 days. Plain sterile water has no preservative and is single-use. For reconstituting research peptides that are drawn from over days or weeks, use bacteriostatic water.
How much bacteriostatic water per peptide vial?
It depends on the concentration you want. 1mL added to a 10mg vial gives 10mg/mL; 2mL gives 5mg/mL. The reconstitution calculator works this out for any vial size and target concentration.
How long does bacteriostatic water last after opening?
28 days after the first puncture, per USP <797> beyond-use dating for multiple-dose containers, provided it is stored at room temperature and the stopper is swabbed before each entry.
Which peptides should not be reconstituted directly in bacteriostatic water?
A few hydrophobic peptides — in the ClaraScience range, notably AOD-9604 and Tesamorelin — dissolve poorly at neutral pH. Dissolve those in a small volume of acetic acid water first, then top up with bacteriostatic water.
Is bacteriostatic water included with peptide orders?
It is sold separately so you can choose the volume you need; it is included in the ClaraScience research stacks. For laboratory research use only — not for human or animal use, and not approved by the TGA for therapeutic use.
