Which one to choose: Bacteriostatic Water vs. Sterile Water

What is the difference between bacteriostatic water vs. sterile water for injection? Although both of these types of water are sterile, the difference between bacteriostatic water and sterile water is that other sterile waters for injection do not contain a bacteriostatic agent. That means, they are single-dose vials and should be discarded after a single-use.

What is bacteriostatic water?

Bacteriostatic Water (bacteriostatic water for injection) is a highly purified, sterilized water containing 0.9% benzyl alcohol that is used to dilute or dissolve medications to the appropriate consistency for injection. Bacteriostatic water (BW) has a pH of about 5.7. The container can be re-entered multiple times (usually by a sterile needle) and the benzyl alcohol is added to ensure that bacteria does not grow in the water as diluting medications with tainted water can have some severe consequences. The benzyl alcohol in the water makes bacteriostatic water ideal for diluting any drug that will be administered by intramuscular, intravenous, or subcutaneous injection. Once a vial of bacteriostatic water is opened, the benzyl alcohol will usually prevent the growth of bacteria for up to 28 days.

There are not many side effects associated with using bacteriostatic water. Although rarely, but they can occur, those side effects are more related to the drug that is dissolved in the bacteriostatic water. You should never inject bacteriostatic water without mixing in any medications because the benzyl alcohol in it causes the red blood cell lysis. Lysis is the breaking down of a cell or membrane. Other side effects from bacteriostatic water have been reported to include tissue death, venous thrombosis, infection at the injection site, fever, abscess formation as well as a febrile response. In case any of the mentioned side effects are present, it is highly advisable to discontinue the use of bacteriostatic water and consult a doctor.

What is sterile water?

Sterile water is water that has no additives or preservatives added to it. As it cannot transfer pathogens, it is used mainly used in the medical field. Once a vial of sterile water is open, it should be used completely at once or used once and discarded. This is one of the reasons that vials of sterile water usually contain a few milliliters of the liquid.

There are no adverse or bad side effects of using sterile water in small doses, one should never take it intravenously. Although, a small percentage of people report inflammation at the injection site if sterile water is used to dilute peptides that are to be injected intramuscularly. Other side effects can include low blood sodium also known as hyponatremia, fluid overload, allergic reactions (tightness in the chest, swelling of the mouth, face, and lips) fever, redness at the site of injection as well as electrolyte imbalance. In case you experience any of these side effects, you should immediately stop using sterile water for injections and talk to a doctor.

Which one is better?

Bacteriostatic water is better when diluting any medication because it offers better solubility for the most part. Also, if you are experimenting with new peptides, it is always best to use bacteriostatic water to dilute the peptides. In case you have any issue diluting peptides in bacteriostatic water, you should add a small amount of 10% aqueous acetic acid for basic peptides and aqueous ammonia for acidic peptides. Most peptide packages contain mixing instruction. It is always advisable to carefully read them before trying to reconstitute the peptides. It could be potentially harmful to try to reconstitute a peptide meant for mixing with bacteriostatic water with sterile water. You cannot simply replace bacteriostatic water with sterile water and vice versa, as they are not the same thing.