What Is Bacteriostatic Water?
Bacteriostatic water for injection (BAC water) is sterile water containing 0.9% benzyl alcohol as a preservative. The benzyl alcohol inhibits — but does not completely destroy — bacterial growth, allowing the solution to be used for multiple draws from a multi-dose vial without microbial contamination. This makes it the standard choice for reconstituting lyophilized peptides that will be used across multiple research sessions.
BAC water is distinct from sterile water for injection (SWFI), which contains no preservative and must be used immediately upon opening, and from normal saline (0.9% NaCl), which can affect peptide stability.
Why BAC Water Over Other Diluents?
| Diluent | Preservative | Multi-Use | Best For |
|---|---|---|---|
| Bacteriostatic Water | 0.9% benzyl alcohol | Yes (28–30 days) | Most peptide reconstitution |
| Sterile Water (SWFI) | None | No — single use only | Single-use reconstitution |
| Normal Saline (0.9% NaCl) | None | No | IV dilutions (not recommended for peptides) |
| Acetic Acid (0.6%) | None | No | Some proteins (e.g. GH, IGF-1) |
Step-by-Step Reconstitution Protocol
Materials Needed
- Lyophilized peptide vial
- Bacteriostatic water vial (Evo Peptides 10mL or 30mL)
- 1mL sterile syringe (insulin-type preferred for precision)
- Sterile needles (typically 27–29 gauge)
- Alcohol swabs (70% isopropyl)
- Permanent marker for labeling
Reconstitution Steps
- Preparation: Allow the lyophilized peptide vial to reach room temperature (15–20 minutes). Do not open before this step.
- Swab stoppers: Clean the rubber stopper of both the peptide vial and the BAC water vial with fresh alcohol swabs. Allow to air dry for 30 seconds.
- Draw BAC water: Using a clean syringe and needle, draw the desired volume of bacteriostatic water.
- Inject slowly: Insert the needle into the peptide vial and inject the BAC water slowly along the inner wall of the vial. Do not inject directly onto the lyophilized powder — this can cause foaming and peptide degradation.
- Dissolve gently: Once all liquid is injected, gently swirl (never shake) the vial until the powder is fully dissolved. The solution should be clear and colorless. Cloudiness or particulates may indicate contamination or degradation.
- Label and refrigerate: Label the vial with the compound name, concentration, and reconstitution date. Refrigerate immediately at 2–8°C.
Reconstitution Ratio Reference
| Vial Size | BAC Water Added | Resulting Concentration | Per 10-unit (0.1mL) Draw |
|---|---|---|---|
| 2 mg | 1 mL | 2,000 mcg/mL | 200 mcg |
| 5 mg | 1 mL | 5,000 mcg/mL | 500 mcg |
| 5 mg | 2 mL | 2,500 mcg/mL | 250 mcg |
| 5 mg | 5 mL | 1,000 mcg/mL | 100 mcg |
| 10 mg | 1 mL | 10,000 mcg/mL | 1,000 mcg |
| 10 mg | 2 mL | 5,000 mcg/mL | 500 mcg |
| 10 mg | 10 mL | 1,000 mcg/mL | 100 mcg |
Storage After Reconstitution
| Condition | Temperature | Max Duration | Notes |
|---|---|---|---|
| Refrigerated (reconstituted) | 2–8°C | 28–30 days | Standard storage |
| Room temperature | 20–25°C | Not recommended | Significant degradation risk |
| Frozen (reconstituted) | −20°C | Not recommended | Ice crystals degrade peptide structure |
Common Questions
How long does BAC water stay sterile after opening?
Bacteriostatic water retains its bacteriostatic properties for approximately 28–30 days after first puncture, when stored at room temperature or refrigerated. The benzyl alcohol preservative maintains an environment inhibitory to bacterial growth.
What if my reconstituted peptide solution is cloudy?
A clear solution is expected for most peptides. Cloudiness may indicate the peptide has not fully dissolved (swirl gently and wait), or it may indicate contamination or degradation. Do not use cloudy solutions in research.
For research use only. Not for human or animal use. Order Bacteriostatic Water here.