Bacteriostatic Water (commonly called BAC Water) is sterile water for injection preserved with 0.9% benzyl alcohol. The benzyl alcohol acts as a bacteriostatic agent, helping inhibit bacterial growth after the vial has been opened, making BAC Water suitable for repeated withdrawals during laboratory research.

Compared with plain sterile water, BAC Water provides greater convenience for ongoing peptide research because the same vial can be accessed multiple times under appropriate sterile handling.

Why use BAC Water?

BAC Water is the preferred reconstitution solvent for the majority of research peptides.

It is commonly used because it:

maintains sterility during repeated withdrawals
contains 0.9% benzyl alcohol as a preservative
is compatible with most lyophilised peptides
provides convenient multi-dose use
is widely used in peptide and protein research laboratories.

BAC Water vs Sterile Water

Although both products begin as sterile water, there is one important difference.

Bacteriostatic Water

contains 0.9% benzyl alcohol
intended for multi-dose use
helps inhibit bacterial growth after opening
commonly used for peptide reconstitution

Sterile Water

contains no preservative
generally intended for single use after opening
offers no bacteriostatic protection between repeated withdrawals.

Is BAC Water suitable for every peptide?

BAC Water is compatible with most peptides available in our catalogue, including:

BPC-157
Thymosin β4 (TB-500)
GHK-Cu
KPV
Semax
Selank
DSIP
MOTS-c
SS-31 (Elamipretide)
CJC-1295 (with and without DAC)
Ipamorelin
Tesamorelin
GHRP-2
GHRP-6
Oxytocin
PT-141
GLP-1 research peptides

Some specialised research peptides like ARA-290 and Kisspeptin may dissolve more efficiently in buffered solutions rather than BAC Water. For those applications, Phosphate Buffered Saline may be a more suitable reconstitution medium depending on the peptide and research protocol.

Handling and storage

For best laboratory practice:

disinfect vial stoppers before every puncture
use sterile syringes and needles
avoid unnecessary exposure to light and heat
discard the vial if sterility is compromised

Although bacteriostatic water inhibits bacterial growth, it does not sterilise contaminated solutions. Proper aseptic technique remains essential.

Product characteristics

Purity: sterile, research grade
Appearance: clear, colorless solution
Composition: sterile water with 0.9% benzyl alcohol
Storage: store at controlled room temperature (20–25°C). Keep sealed and sterile.

Frequently Asked Questions

What is BAC Water?

BAC Water is sterile water containing 0.9% benzyl alcohol, which acts as a bacteriostatic preservative and allows repeated withdrawals from the same vial during laboratory research.

Why is BAC Water preferred over sterile water?

Unlike sterile water, BAC Water contains a preservative that helps inhibit bacterial growth after opening, making it more practical for multi-dose peptide reconstitution.

Does BAC Water kill bacteria?

No. The benzyl alcohol is bacteriostatic, meaning it inhibits the growth of many bacteria rather than sterilising contaminated solutions. Proper sterile handling is still required.

Can every peptide be reconstituted with BAC Water?

Most lyophilised peptides dissolve readily in BAC Water. However, certain peptides may reconstitute more effectively in buffered solutions such as DPBS, depending on their physicochemical properties and the intended laboratory protocol.

How long can BAC Water be used after opening?

When handled aseptically and stored refrigerated, bacteriostatic water is commonly used for up to 28 days after first puncture, consistent with standard laboratory practice.

Is this product intended for human use?

No. This product is supplied exclusively for laboratory and analytical research. It is not intended for human consumption, diagnosis, treatment or prevention of disease.

Related research products

Phosphate Buffered Saline – buffered solution for selected peptides and laboratory applications.
0.22 μm PES Sterile Filters – for sterile filtration of laboratory solutions.
Peptide Reconstitution Guide – learn how to calculate dilution volumes and prepare lyophilised peptides.

NOTE: This is for educational reference only and does not constitute medical advice.

Disclaimer
This product is sold for research purposes only. It is not intended to diagnose, treat, cure, or prevent any disease. Buyer assumes full responsibility for proper handling and use.

benzyl alcohol

Bakteriostatisches Wasser (BAC-Wasser) 0,9%