Most research peptides ship as a lyophilized (freeze-dried) powder that must be reconstituted into solution before use in the laboratory. This guide explains what bacteriostatic water is, how reconstitution is performed in a research setting, and how to calculate concentration. It is written for researchers and is not medical guidance or usage instructions for humans.
What is bacteriostatic water?
Bacteriostatic water is sterile water containing 0.9% benzyl alcohol, a preservative that inhibits the growth of bacteria. The benzyl alcohol is what allows a reconstituted vial to be accessed multiple times over a period of days to weeks while remaining suitable for laboratory work — in contrast to plain sterile water, which has no preservative. This makes bacteriostatic water the most common diluent in peptide-reconstitution research protocols.
Research-use note: Bacteriostatic water and all peptides referenced here are supplied strictly for laboratory research. Nothing in this guide describes or endorses human or veterinary use.
General reconstitution steps (laboratory procedure)
- Allow vials to reach room temperature. Cold powder and diluent can affect handling.
- Sanitize the stoppers. Wipe the rubber stopper of both the peptide vial and the bacteriostatic water vial with an alcohol prep.
- Draw the diluent. Using a sterile syringe, draw the chosen volume of bacteriostatic water.
- Add slowly down the vial wall. Let the water run gently down the inside glass wall of the peptide vial rather than directly onto the powder — peptides are delicate and direct, forceful streams can degrade them.
- Swirl, do not shake. Gently swirl or roll the vial until the powder fully dissolves. Never shake.
- Store refrigerated. Keep the reconstituted solution at 2–8 °C and protected from light.
How to calculate concentration
Concentration is simply the mass of peptide divided by the volume of diluent added. For example, reconstituting a 10 mg peptide vial with 2 mL of bacteriostatic water yields a concentration of 5 mg/mL (5000 mcg/mL). Adding 1 mL instead would yield 10 mg/mL. The amount of diluent does not change the total mass of peptide in the vial — only the concentration of the resulting solution. (Provided as a general research calculation only.)
Storage & handling notes
- Lyophilized powder: store frozen, protected from light, until reconstitution.
- Reconstituted solution: refrigerate at 2–8 °C; avoid repeated temperature cycling.
- Handling: minimize exposure to light, heat, and agitation.
For research use only
All products and information referenced here are intended strictly for laboratory and scientific research use only. They are not for human or animal consumption and are not drugs, foods, supplements, or medical devices. No statement here should be interpreted as medical advice.
Get your reconstitution supplies and research peptides
- Bacteriostatic Water 30ml — sterile reconstitution diluent
- Browse all research peptides
- More research guides — compound-by-compound overviews