USP-Grade Sterile Diluent for Peptide Reconstitution
Last updated: October 2026 · Editorial Policy
Bacteriostatic water (BAC water) is sterile water that contains 0.9% benzyl alcohol as a preservative. The benzyl alcohol inhibits bacterial growth, making the solution safe for multiple withdrawals from a single vial over a period of up to 28 days.
Unlike sterile water for injection – which is single-use only – bacteriostatic water is specifically designed for multi-dose applications. This makes it the standard diluent for reconstituting lyophilized (freeze-dried) peptides and other research compounds.
Each vial contains purified water processed to USP (United States Pharmacopeia) standards with 0.9% benzyl alcohol (v/v) added as a bacteriostatic preservative.
Proper reconstitution technique preserves peptide integrity and ensures accurate dosing. Follow these steps for optimal results:
| Step | Instructions |
|---|---|
| 1. Prepare | Wipe vial stoppers (both BAC water and peptide) with alcohol swabs. Allow to air dry. |
| 2. Draw | Using a sterile syringe, withdraw the desired volume of bacteriostatic water from the vial. |
| 3. Inject | Insert the needle into the peptide vial and release the water slowly against the glass wall – never spray directly onto the powder. |
| 4. Mix | Gently swirl the vial until the powder is fully dissolved. Do not shake, as this can denature the peptide. |
| 5. Store | Refrigerate the reconstituted solution at 2–8°C and use within 28 days. |
Ships same day • Multi-use vial • 28-day stability after opening
Sterile water contains no preservative and must be discarded after a single use. Bacteriostatic water contains 0.9% benzyl alcohol, which inhibits bacterial growth and allows for multiple withdrawals over 28 days. For multi-dose peptide reconstitution, bacteriostatic water is the standard choice.
The volume depends on the peptide and your desired concentration. A common starting point is 1–2 mL per vial, which simplifies dosing calculations. Check the specific peptide’s product page for recommended reconstitution volumes.
Store unopened vials at room temperature (15–30°C) away from direct light. Once punctured, refrigerate at 2–8°C and use within 28 days. Do not freeze.
Yes. The benzyl alcohol preservative allows multiple punctures over 28 days. Always use a new sterile syringe and needle for each withdrawal, and wipe the stopper with an alcohol swab before every use.
Bacteriostatic water is USP-grade and manufactured under sterile conditions for use as a diluent. It is the standard reconstitution medium used in clinical and research settings for subcutaneous and intramuscular preparations.
Essential for every peptide protocol. Bacteriostatic water is the foundation of safe reconstitution – pair it with any peptide in our catalog.
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