Bacteriostatic water allows multiple draws over 28 days when refrigerated, making it the standard for research-grade peptide reconstitution protocols requiring repeated access
Sterile water is designed for single-use applications only
Standard protocol allows 14 days at 0.25mg before moving to 0.5mg
Method Absorption Rate Advantages Disadvantages Oral pills 1.2-40% depending on intrinsic factor Convenient, widely available Poor absorption, especially with age or GI issues Sublingual Slightly better than pills No need for intrinsic factor, easy to use Still less effective than injectable forms In-clinic IM injection Nearly 100% Highly effective, professionally administered Requires clinic visits, potential travel and waiting time At home B12 injection Nearly 100% Highly effective, convenient, no travel needed Requires training, prescription, and comfort with self-injection IV infusion 100% Immediate delivery to bloodstream Most expensive, requires professional administration For many people especially those with serious deficiencies, digestive disorders, or pernicious anemia at home B12 injection offers the sweet spot of effectiveness and convenience

This is what makes bacteriostatic water the long-established standard diluent for reconstituting lyophilized research peptides such as BPC-157, retatrutide, GHK-Cu, and tirzepatide
Nat Rev Dis Primers 3 , 17040 (2017)