The sterile water most research peptides get dissolved in before injection — it contains a small amount of preservative that keeps bacteria from growing in the vial.0.9% benzyl alcohol is the preservative. It allows the same vial to be used multiple times over several weeks when refrigerated, unlike plain sterile water (single-use only). Do not use bacteriostatic water in neonates — benzyl alcohol is toxic in newborns at doses that are safe in adults. Distinct from normal saline (0.9% NaCl) and sterile water for injection, both of which lack preservative.