Many people wonder “what is the difference between sterile water, and bacteriostatic water?” The answer is quite easy to understand and can be explained easily. Sterile water, is water that is sterile and good for a 1 time injection. It does not include anything to prevent bacteria, so once it is penetrated it needs to be used entirely or disposed of. Bacteriostatic water is simply sterile water, with benzyl alcohol added to prevent bacteria growth in the water. Bacteriostatic water can be used for multiple injections spread over up to 30 days. Without the benzyl alcohol the water would not be safe for multi injection use. This is why it is very important to only use bacteriostatic water while doing the research with Peptides. Bacteriostatic water is needed for ANY research of all Peptides, and if you substitute sterile water in its place you are risking the efficiency of the Peptide.
Peptides can have widely varying solubility properties, depending largely on their primary sequence. While many peptides dissolve easily in bacteriostatic water (Containing 0.9% (9 mg/mL) of benzyl alcohol), some, especially those containing multiple hydrophobic amino acid residues, may not readily dissolve.
As a general procedure, we recommend first attempting to reconstitute peptides in bacteriostatic water. If solubility is still a problem, addition of a small amount of dilute (approximately 10%) aqueous acetic acid (for basic peptides) or aqueous ammonia (for acidic peptides) may facilitate dissolution of the peptide”