Every vial needs itPeptides ship as a dry powder. Bacteriostatic water is what you mix them with before you can draw a dose. NAD+ is the one exception: it takes Hospira water.
One bottle covers a lot30 ml is enough for roughly 15 vials at the standard 2 ml mix.
Keeps in the fridgeThe benzyl alcohol keeps the water sterile for repeated draws over about a month once opened.