Supplies · 2 min read

Bacteriostatic water guide

Bacteriostatic water is water with 0.9% benzyl alcohol added as a preservative. That preservative is the entire reason it can be drawn from more than once.

Bacteriostatic vs sterile vs distilled

TypePreservativeMulti-drawUse with peptides
Bacteriostatic water0.9% benzyl alcoholYesStandard choice
Sterile waterNoneSingle use onlyOnly for one-shot use
Distilled waterNone, not sterileNoNever

If you plan to draw more than one dose from a reconstituted vial — which is almost always the case with a 30 mg peptide vial — bacteriostatic water is the correct choice.

How much to use

There is no fixed rule; the amount you add sets the concentration. Choose the volume that makes your smallest planned dose easy to read on a U-100 syringe. For a 30 mg vial, 3 mL is the usual answer because it gives 10 mg/mL.

A 10 mL bacteriostatic water vial therefore covers roughly three 30 mg peptide vials at 3 mL each, with a little left over.

Storage and handling

  • Keep the vial refrigerated at 2–8 °C once opened, and protect it from light.
  • Wipe the stopper with alcohol before every draw.
  • Never top up a bacteriostatic vial with anything else.
  • Discard if the solution is cloudy, discoloured, or contains particles.

Frequently asked questions

How long does bacteriostatic water last after opening?

The benzyl alcohol preservative is generally treated as good for about 4 weeks of multi-draw use after first puncture when refrigerated, though many labs apply a shorter internal limit.

Can I use sterile water instead?

Only if the entire vial will be used in a single draw. Sterile water contains no preservative, so repeated punctures risk contamination.

Where can I buy bacteriostatic water in the Philippines?

Origen ships 10 mL bacteriostatic water nationwide, and it is included in the Origen starter and research bundles alongside syringes and alcohol pads.

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All Origen products are supplied for laboratory research use only and are not for human or veterinary consumption. Nothing on this page is medical advice. Last updated 2026-08-03.