Bacteriostatic water
Bacteriostatic water is sterile water with 0.9% benzyl alcohol added. The alcohol stops bacteria from growing, which is what makes it safe for a vial you'll stick a needle into again and again.
Why not plain sterile water?
Plain sterile water is sterile only until the first needle goes in. With no preservative, every later draw is a chance for bacteria to grow. Bacteriostatic water stays usable for multiple draws.
How long it lasts
- An opened vial of bacteriostatic water is typically good for 28 days.
- A peptide mixed with it is usually kept in the fridge and used within about 3–4 weeks.
- Throw out any water that looks cloudy or has particles.
Who should avoid it
Benzyl alcohol isn't safe for newborns, and some people are sensitive to it. If you react to it, with stinging that doesn't fade or a rash, stop and talk to a doctor.
Get it
We may earn a commission from these links.Common questions
Is bacteriostatic water the same as saline?
No. Saline is salt water. Bacteriostatic water is sterile water with a preservative. Some bacteriostatic saline exists, but peptide guides mean bacteriostatic water.
Why does it sting a little?
The benzyl alcohol can sting briefly as you inject. That's normal and fades quickly.