Bacteriostatic Water

About bacteriostatic water for peptides (research diluent)

 

Bacteriostatic water for peptides is sterile USP-grade water preserved with 0.9% benzyl alcohol. It is the standard diluent that researchers use to reconstitute lyophilized peptides before in vitro and preclinical investigation. The benzyl alcohol preservative inhibits microbial growth in the vial after each needle penetration, which is what makes the same vial usable across multiple research reconstitutions over time.

Velora Research supplies bacteriostatic water in 3ml and 10ml sterile sealed vials, sized to match the volumes typical research-peptide protocols call for. Every vial ships with a multi-dose stopper that supports repeated withdrawals within the labeled stability window. The product is supplied solely for laboratory research-peptide reconstitution and is not for human or veterinary use.

What is bacteriostatic water?

 

Bacteriostatic water is sterile water (the same USP-grade Sterile Water for Injection used in pharmaceutical reconstitution) with the addition of benzyl alcohol as a bacteriostatic preservative at a concentration of 0.9% (9 mg per mL). The benzyl alcohol inhibits bacterial growth without sterilizing the solution outright, which lets researchers withdraw from the same vial multiple times across the labeled stability period rather than discarding the unused portion after a single use.

Bacteriostatic water is the most commonly used diluent for lyophilized research peptides because:

• Compatibility. Most synthetic research peptides are stable in mildly acidic to neutral aqueous solution. BAC water’s pH of 4.5 to 7.0 sits inside that range.
• Multi-dose use. The benzyl alcohol preservative allows multiple withdrawals from the same vial across the labeled stability window, which matches the way most research protocols draw down a peptide stock over a series of experiments.
• Documented composition. USP-grade purity and known preservative content reduce variables in research designs that depend on reproducibility.

Bacteriostatic water vs sterile water vs normal saline

Researchers selecting a diluent for peptide reconstitution often compare three options. Summary of how the three differ at the formulation level:

Attribute	Bacteriostatic water (BAC water)	Sterile water for injection	0.9% sodium chloride (saline)
Preservative	0.9% benzyl alcohol	None	None
Sodium content	None	None	Yes (0.9%)
pH range	4.5 to 7.0	5.0 to 7.0	4.5 to 7.0
Multi-dose use	Yes (preservative inhibits microbial growth)	Single use only	Single use only
Common research use	Standard peptide reconstitution across most protocols	Single-use reconstitution; saline-sensitive peptides	Saline-stable peptides; certain assays requiring isotonic vehicle
Why most peptide protocols use it	Multi-dose convenience plus pH compatibility	Best for single-experiment use	Required only when saline is part of the protocol

For most lyophilized research peptides, bacteriostatic water is the diluent of choice. Sterile water for injection is appropriate when a single-use reconstitution is required or when benzyl alcohol could interfere with the assay. Normal saline is used only when the research protocol specifies an isotonic vehicle.

Key specifications

Attribute	Specification
Product	Bacteriostatic water for peptides (BAC water)
Composition	Sterile USP-grade water with 0.9% benzyl alcohol preservative
Benzyl alcohol concentration	9 mg per mL (0.9%)
pH range	4.5 to 7.0
Form	Sterile aqueous solution (clear, colorless liquid)
Available vial sizes	3 mL and 10 mL
Vial closure	Sealed rubber stopper supporting multi-dose needle penetration
Shelf life (unopened)	Up to 24 months under proper storage conditions
Stability after first puncture	Up to 28 days when stored properly between withdrawals
Storage temperature	15 to 25°C (room temperature), protected from light. Do not freeze.
Intended use	Research-peptide reconstitution in laboratory settings only

 

Bacteriostatic water pricing

Vial size	Price (USD)	Best for
3 mL	$6.99	Smaller pilot protocols, single-peptide research designs, lower per-vial concentration targets
10 mL	$9.99	Multi-vial reconstitution rounds, larger peptide vials (70mg blends, 100mg compounds), better per-mL value

 

Free US shipping applies on orders over $200. Most peptide orders that include bacteriostatic water cross the free-shipping threshold automatically. International orders are accepted in accordance with applicable research regulations.

How to mix peptides with bacteriostatic water

The procedure below is the standard reconstitution workflow used in research peptide laboratories. Follow your study protocol’s specific instructions if they differ. The general method:

1. Gather materials: the sealed peptide vial, a sealed bacteriostatic water vial, a sterile syringe and needle sized for the target volume (typically an insulin-style U-100 syringe for small volumes), and an alcohol prep pad.
2. Calculate the target concentration. Decide what mg per mL stock solution your protocol requires, then divide the peptide vial amount by the target concentration to determine the volume of BAC water to draw.
3. Wipe both vial stoppers with the alcohol pad.
4. Draw the calculated volume of bacteriostatic water into the syringe.
5. Insert the needle into the peptide vial at approximately a 45-degree angle, with the tip pointed at the inside wall of the vial. Slowly release the bacteriostatic water down the side wall of the peptide vial rather than directly onto the lyophilized powder.
6. Remove the syringe. Allow the peptide to dissolve naturally. Gently swirl the vial in your hand. Do not shake. Shaking creates foam and can degrade peptide integrity.
7. Once the solution is fully clear, label the vial with the reconstitution date, concentration, and peptide identity.
8. Refrigerate the reconstituted vial at 2 to 8°C. Use within the stability window established by the research protocol.

Common reconstitution math

Quick reference for the most common research-peptide vial sizes and the resulting stock concentration at different BAC water volumes:

Peptide vial	BAC water added	Resulting concentration	Notes
5 mg	1 mL	5 mg/mL	Most concentrated; for protocols requiring small dose volumes
5 mg	2 mL	2.5 mg/mL	Balanced; common pilot ratio
10 mg	1 mL	10 mg/mL	High concentration; precise small-volume dosing required
10 mg	2 mL	5 mg/mL	Standard reconstitution for most 10mg peptide vials
10 mg	5 mL	2 mg/mL	Lower concentration; easier to measure larger dose volumes
70 mg blend (e.g., GLOW)	5 mL	14 mg/mL	Common ratio for high-mg proprietary blends
100 mg (e.g., GHK-Cu)	5 mL	20 mg/mL	Standard ratio for 100mg copper peptide vials

If your protocol uses a U-100 insulin syringe (100 units = 1 mL), 10 units equals 0.1 mL, 25 units equals 0.25 mL, and 50 units equals 0.5 mL. Multiply the syringe volume by the stock concentration to determine the mg dose drawn.

Storage and stability

• Unopened: store sealed vials at 15 to 25°C (room temperature), protected from direct light. Do not freeze. Unopened shelf life is up to 24 months.
• After first puncture: the benzyl alcohol preservative supports up to 28 days of multi-dose use when the vial is stored properly between withdrawals.
• Reconstituted peptide vials: refrigerate at 2 to 8°C. Stability after reconstitution depends on the peptide, not on the BAC water. Refer to peptide-specific stability data and your study protocol.
• Visual check: discard any vial that appears cloudy, discolored, or contains visible particulate matter.

Why buy bacteriostatic water for peptides from Velora Research

• USP-grade composition. Sterile water for injection with 0.9% benzyl alcohol preservative at the documented 9 mg per mL concentration.
• Two vial sizes. 3 mL and 10 mL options to match pilot protocols and larger multi-vial reconstitution rounds.
• Multi-dose stoppers. Rubber closures support repeated withdrawals within the labeled stability window, which matches how research peptide stocks are typically drawn down.
• US-based 2-day shipping. Free over $200; most orders process within 1 to 2 business days. Adding BAC water to a peptide order is often the simplest way to clear the free-shipping threshold.
• Compliance-first sales policy. Sales restricted to qualified laboratories, institutions, and research professionals. Research-use-only terms acknowledged at checkout.