Bacteriostatic Water

Product Specifications

• Composition: Water for Injection, USP + 0.9% Benzyl Alcohol (w/v)
• Grade: USP (United States Pharmacopeia)
• Benzyl Alcohol: 0.9% w/v bacteriostatic preservative
• pH: 4.5-7.0
• Appearance: Clear, colourless solution
• Vial Type: Multi-dose borosilicate glass vial with rubber septum
• Sterility: Sterile-filtered (0.22 micron)
• Available In: 10mL and 30mL vials

Storage

Store bacteriostatic water at room temperature (15-30°C) away from direct sunlight before opening. Once opened, store at 2-8°C and use within 28 days. Do not freeze. Discard if the solution becomes cloudy, discoloured, or shows any visible particulate matter.

Intended Use

Bacteriostatic water is intended solely for use as a reconstitution diluent for lyophilized research compounds in laboratory settings. Not for direct administration or therapeutic use.

What Is Bacteriostatic Water and Why Is It Used for Peptide Reconstitution?

• Bacteriostatic water is the standard solvent for reconstituting lyophilized peptides in research settings. When a peptide vial arrives as a freeze-dried powder, it must be dissolved in a sterile liquid before it can be used in experimental protocols. BAC water provides an inert, sterile, compatible medium that dissolves peptides without degrading their structure.
• The 0.9% benzyl alcohol in BAC water acts as a bacteriostatic agent — it does not sterilise the solution, but it inhibits bacterial growth after the vial septum has been punctured. This is critical for multi-dose research protocols where the same vial is accessed repeatedly over days or weeks. Each puncture introduces a small contamination risk; the benzyl alcohol mitigates this and extends usable vial life.
• Bacteriostatic water for peptides is specifically recommended for BPC-157, TB-500, ipamorelin, CJC 1295, sermorelin, semaglutide, tirzepatide, GHK-Cu, and all other lyophilized peptide compounds. It is the first product to order alongside any peptide purchase if you do not already have it on hand.

Bacteriostatic Water vs Sterile Water for Peptide Reconstitution

• Plain sterile water contains no preservative. Once the vial septum is punctured, it should be used in a single session — repeat punctures carry contamination risk without a bacteriostatic agent present. Sterile water is suitable for single-dose reconstitution protocols where the entire vial contents are used at once.
• Bacteriostatic water is the preferred choice for peptide reconstitution in any multi-dose research protocol. The benzyl alcohol preservative supports safe repeated access to the same vial, making it practical for experiments that span multiple days or weeks. Reconstituted peptides stored in BAC water at 2-8°C typically remain stable for 28-30 days.
• Normal saline (0.9% sodium chloride) is occasionally used as an alternative diluent for peptides in some protocols, particularly for intraperitoneal or intravenous administration in animal models. However, saline lacks a bacteriostatic preservative and does not support multi-dose use. For most research applications, bacteriostatic water remains the optimal choice for its compatibility, stability, and preserved sterility.

How Much Bacteriostatic Water to Add to a Peptide Vial

The volume of BAC water added determines the concentration of the reconstituted solution and therefore how many units to draw on an insulin syringe per dose. A common starting point:

• Standard peptides (BPC-157, TB-500, ipamorelin, CJC 1295, sermorelin): 1-2mL of bacteriostatic water per vial. Adding 1mL to a 5mg vial gives a concentration of 5mg/mL (5000mcg/mL). Adding 2mL gives 2.5mg/mL.
• GLP-1 peptides (semaglutide, tirzepatide): 2-3mL is common to allow for smaller, more precise dose increments given the lower per-dose amounts used in research protocols.
• Use our free peptide reconstitution calculator to calculate exactly how many units to draw for any dose, vial size, and BAC water volume combination.

Step-by-Step Reconstitution Protocol

• 1. Gather supplies: Bacteriostatic water vial, peptide vial, insulin syringe, alcohol swabs. Ensure all surfaces and hands are clean.
• 2. Swab both vial tops with a fresh alcohol swab and allow to air dry for 10-15 seconds.
• 3. Draw BAC water: Insert the syringe into the BAC water vial and draw the desired volume (e.g. 1mL or 2mL).
• 4. Inject slowly: Insert the syringe into the peptide vial and direct the BAC water slowly down the inside wall of the vial. Do not inject directly onto the lyophilized powder — this can damage the peptide structure.
• 5. Dissolve gently: Once all liquid has been added, gently swirl the vial in a slow circular motion until the powder is fully dissolved. Do not shake or vortex.
• 6. Store correctly: Label the vial with the date of reconstitution. Store at 2-8°C. Use within 28-30 days.

How to Draw a Dose from a Reconstituted Vial

Use a sterile insulin syringe for each draw. Swab the vial septum with an alcohol swab before each access. Insert the needle and withdraw the calculated volume. Use the peptide calculator to determine the exact number of units on your syringe for your target dose. Never reuse syringes.