Reconstitution Water

Bacteriostatic water is sterile water that contains 0.9% benzyl alcohol as a preservative. The benzyl alcohol prevents bacterial growth, which allows the vial to be used multiple times over a period of up to 28 days. It is the standard solvent for reconstituting lyophilized (freeze-dried) peptides in research settings. "Bacteriostatic" literally means "bacteria-stopping."

Bacteriostatic water contains 0.9% benzyl alcohol (preservative) and is safe for multi-dose use over 28 days. Sterile water contains no preservative and must be used in a single session, then discarded. Sodium chloride (saline) contains salt but no antimicrobial agent, and the chloride ions can interfere with certain peptides (notably GHK-Cu). For peptide research, bacteriostatic water is the standard choice for multi-dose vials.

The amount depends on the desired concentration. The formula is: peptide amount (mg) divided by water volume (mL) equals concentration (mg/mL). Common reconstitution volumes are 1-3mL per vial. For example, adding 2mL to a 10mg vial yields 5mg/mL. Adding 1mL to a 5mg vial yields 5mg/mL. Choose a volume that makes your desired research quantities easy to measure.

Unopened bacteriostatic water is stable for 2-3 years (check the expiration date on the vial). Once punctured, use within 28 days and then discard. The benzyl alcohol preservative prevents bacterial growth but does not eliminate it indefinitely. After 28 days, microbial contamination risk increases.

Store at room temperature (20-25C / 68-77F) away from direct sunlight, heat, and moisture. Do not freeze bacteriostatic water. Do not refrigerate unless specifically directed by the manufacturer. Room temperature storage is standard.

Yes. Oxytocin and desmopressin are sensitive to benzyl alcohol and should be reconstituted with sterile water for injection instead. Most other research peptides are compatible with bacteriostatic water. When in doubt, check the peptide manufacturer's reconstitution guidelines.

Absolutely not. Only pharmaceutical-grade bacteriostatic water or sterile water for injection should be used. Tap water and distilled water are not sterile, not tested for endotoxins, and may contain particulate matter or microbial contaminants that will compromise the peptide and the research.

Inspect the solution before each use. Discard immediately if the solution appears cloudy, hazy, or contains visible particles, fibers, or discoloration (unless expected, as with the blue tint from GHK-Cu). A properly reconstituted peptide in bacteriostatic water should be clear and colorless (or light blue for copper peptides). Any change in appearance indicates potential degradation or contamination.

Every batch undergoes third-party HPLC and mass spectrometry testing. HPLC confirms purity (99%+ standard). Mass spectrometry confirms molecular identity. A batch-specific Certificate of Analysis is provided with every purchase and available for download directly on this page.

All Kern products ship same-day (orders placed before 1pm EST). Lyophilized peptides are shipped at ambient temperature and are stable during transit. Upon receipt, store at -20C for long-term stability or 2-8C for near-term use. If the product arrives damaged, contact us within 7 days with photos for a free replacement.

Price differences usually reflect differences in purity, testing standards, and manufacturing quality. Low-cost vendors may skip mass spectrometry verification (which confirms you actually have the right molecule), use lower-grade raw materials, or skip sterility and endotoxin testing. Kern tests every batch with both HPLC and mass spec, and our CoAs are available before you buy.