Peptide Water

Auxiliary reagent for Research Use Only (RUO), intended exclusively for preparing solutions in laboratory research. Not for consumption or use in humans.

Water for peptides – bacteriostatic water for reconstitution of lyophilisates

Water for peptides (bacteriostatic water) is sterile water with the addition of 0.9% benzyl alcohol, intended for reconstitution of freeze-dried research peptides in laboratory conditions. Benzyl alcohol acts as a bacteriostatic agent, inhibiting the growth of microorganisms in the solution once the vial is opened. It is a basic laboratory accessory necessary for the proper preparation of working solutions from peptides in the form of a lyophilisate. Browse the available variants of peptide water in the One Peptides offer.

See also the full section performance category.

What is peptide water?

Peptide water, also referred to as Bacteriostatic Water for Injection (BWI), is sterile purified water with the addition of 0.9% benzyl alcohol as a preservative. Benzyl alcohol at this concentration inhibits the multiplication of bacteria and other microorganisms, which allows the solution to be withdrawn multiple times from the same vial without the risk of microbiological contamination.

Bacteriostatic water is a standard solvent used in laboratories to reconstitute peptides supplied in freeze-dried (freeze-drying) form. Lyophilization is the process of removing water from the preparation under reduced pressure, which ensures long-term stability of the substance. Before use, the lyophilisate must be dissolved in an appropriate solvent – and this is what bacteriostatic water does.

The reconstitution process involves slowly adding bacteriostatic water to the vial with the lyophilisate, most often along the vessel wall, in order to avoid foaming and degradation of the peptide. After reconstitution, the solution should be kept cold (2-8 degrees Celsius) and used within the specified time, according to the guidelines for the given peptide. Peptide Water is not a medicinal product or dietary supplement – it is a laboratory accessory.

Peptide water variants available

Each vial of bacteriostatic water is delivered in sterile packaging with protection against contamination. The benzyl alcohol content is 0.9% (w/v), which is the standard concentration used in research laboratories.

Which variant of peptide water should I choose?

Bacteriostatic water is available from One Peptides in a 10 ml vial. This volume is sufficient to reconstitute several vials of peptide – suitable for both smaller research projects and when working with single substances. Please remember that after opening the vial for the first time, bacteriostatic water retains its properties for up to 28 days when stored at a temperature of 2-8 degrees Celsius.

How is peptide water different from other types of water?

Bacteriostatic water vs distilled water
Distilled water is water purified by distillation, free of minerals and impurities, but does not contain a bacteriostatic agent. This means that once a container of distilled water is opened, there is no protection against microbial growth – any amount taken should be used only once. Bacteriostatic water, thanks to the presence of 0.9% benzyl alcohol, allows for multiple withdrawals from the same vial within a period of up to 28 days. In the context of peptide reconstitution, bacteriostatic water is the standard choice to protect against contamination between collections.

Bacteriostatic water vs physiological saline (0.9% NaCl)
Physiological saline is a solution of 0.9% sodium chloride in water – it is isotonic, but does not contain a bacteriostatic agent (unless it is the bacteriostatic version of saline). Standard saline is intended for single use. Moreover, the presence of sodium and chlorine ions may in some cases affect the stability of peptides sensitive to the ionic strength of the solution. Bacteriostatic water is preferred for reconstitution of most freeze-dried peptides because it does not introduce additional ions into the solution.

Bacteriostatic water vs water for injection (WFI)
Water for Injection is sterile, non-pyrogenic water without any additives. It is intended for single use – once the container is opened, all contents should be used or disposed of. Bacteriostatic water differs from WFI in the presence of benzyl alcohol, which allows for repeated sampling. In laboratory practice, bacteriostatic water is more convenient when working with multiple vials of peptides in staggered experimental sessions.

FAQ – Frequently asked questions

1. Why is bacteriostatic water used to reconstitute peptides and not plain water?
Bacteriostatic water contains 0.9% benzyl alcohol, which inhibits the growth of microorganisms in the solution. This allows for repeated withdrawals from the vial without the risk of microbiological contamination. Ordinary distilled water or water for injection does not have this protection and is intended for single use.

2. How long can an opened vial of bacteriostatic water be stored?
After first opening, the vial of bacteriostatic water should be stored at a temperature of 2-8 degrees Celsius. The standard shelf life after opening is up to 28 days. After this time, it is recommended to use a new vial to maintain sterility.

3. How to properly reconstitute a lyophilized peptide?
Bacteriostatic water should be taken with a sterile syringe and slowly added to the vial with the lyophilisate, directing the stream along the inner wall of the vial. Do not shake the vial – instead swirl it gently until the lyophilisate is completely dissolved. The volume of water added depends on the required working concentration.

4. Is bacteriostatic water a medicinal product?
NO. The bacteriostatic water offered by One Peptides is a laboratory accessory intended for the reconstitution of peptides in research conditions. It is not a medicinal product, dietary supplement or agent for clinical use.

5. Can I use distilled water instead of bacteriostatic water?
Technically, reconstitution with distilled water is possible, but the solution obtained in this way does not have bacteriostatic protection and must be used once or immediately frozen in aliquots. Bacteriostatic water is the preferred solvent in standard laboratory protocols due to its ability to be sampled repeatedly.

Quality and standards at One Peptides

The bacteriostatic water offered by One Peptides is produced in sterile conditions and delivered in vials with protection against contamination. Each batch has documentation confirming sterility and benzyl alcohol concentration (0.9% w/v). One Peptides uses quality control procedures to ensure product compliance with the requirements for laboratory solvents.