Bacteriostatic Water

$10 In stock

For research use only. Not for human or veterinary use.

Bacteriostatic water is sterile water for injection with benzyl alcohol added as a preservative, so a vial can be entered more than once.¹ Its FDA-approved label limits it to diluting or dissolving injectable drugs.¹ The supplier lists 0.9% benzyl alcohol.

Specifications

Contents	Sterile water for injection with benzyl alcohol as a bacteriostatic preservative¹
Benzyl alcohol	0.9% as listed by the supplier (the USP 0.9% strength is 9 mg per mL)¹
Container type	Multiple-dose vial: repeated withdrawals can be made¹
Labeled use (FDA-approved product)	Diluent or solvent only, for drugs given intravenously, intramuscularly or subcutaneously¹
Label warning	Not for use in neonates¹
Ships from	USA
Category	Peptide Supplies
Storage	Unopened vials are kept at 20 to 25 °C (68 to 77 °F) under the FDA-approved label.¹ Once a vial is entered, it is dated and discarded within 28 days unless its maker's label gives another date.³⁴

Bulk and wholesale orders

Labs that mix many vials can order bulk bacteriostatic water through a wholesale account. As a bacteriostatic water supplier, we confirm bacteriostatic water wholesale terms on application.

Wholesale details Apply for a wholesale account

Guides and calculator

How to reconstitute a peptide vial
Reconstituting a lyophilized peptide step by step: the supplies, the diluent, the math and storage after mixing.
How subcutaneous injections are given
How prescribed subcutaneous injections are given: sites, rotation, sterile technique and sharps disposal, from clinical sources.
How to store peptides
How lyophilized and reconstituted peptides are stored: temperature, light, moisture and how long they keep, from manufacturer guidance.
Reconstitution calculator
Enter the peptide amount and the diluent volume and get the concentration per mL and per syringe unit. Shows the formula. For reference only.

What it is

The benzyl alcohol limits the growth of bacteria that get into the vial during repeated use.¹³ Hospira's FDA-approved water comes with 0.9% (9 mg per mL) or 1.1% (11 mg per mL) benzyl alcohol.¹

FDA approved Hospira's version in 1982 and lists it as a prescription product.² In 2026 warning letters to three peptide sellers, FDA said bacteriostatic water sold alongside peptides that need mixing is intended for injection with them, and called it an unapproved new drug.¹⁰¹¹¹² That held despite research-use labeling: FDA cited website evidence that the products were intended as drugs for human use.¹⁰¹¹¹²

Three label warnings apply:

Not for newborns. The label links benzyl alcohol to toxicity in newborns.¹
Not for a vein on its own. Without enough dissolved drug, it may cause hemolysis.¹
Not for every drug. Some drugs are incompatible with benzyl alcohol; AmBisome must be mixed with sterile water that has no bacteriostatic agent.¹⁹

Bacteriostatic water for sale here comes as a single vial, and the bacteriostatic water price shown above is per vial. The supplier does not state the vial's volume or maker. To buy bacteriostatic water online, add the vial to your cart.

How it is used

In the lab it dissolves a freeze-dried powder into a solution of known strength. Concentration is the amount in the vial divided by the volume added, so 10 mg in 2 mL gives 5 mg per mL. The reconstitution calculator does that division, and the reconstitution guide lists the lab steps.

At every entry, wipe the rubber septum with alcohol, use a new needle and a new syringe, and never leave a needle in the stopper.⁵⁴ The preservative does not replace that care: CDC notes it has no effect on viruses and does not fully protect against bacteria.⁴ Use the water only if it is clear and the seal is intact.¹

Storage and disposal

The water's label says to use a mixed drug promptly and not to store it unless that drug's maker directs otherwise.¹ For example, Egrifta WR keeps 7 days at room temperature,⁶ Novarel 30 days refrigerated⁸ and the Omnitrope 5.8 mg vial 21 days refrigerated.⁷ The storage guide covers peptides after mixing. Needles and syringes used with the vial go into a sharps disposal container right after use,¹³ as the injection guide explains.

Frequently asked questions

Can I buy bacteriostatic water at CVS?

In the US, the FDA-approved product (Hospira, NDA 018802) has prescription marketing status and its label says 'Rx only', so a pharmacy supplies it as a prescription item.²¹ Our sources do not cover any one chain's stock. The vial on this page is listed for laboratory research use under our research use policy.

How many mL of bacteriostatic water to mix with peptides?

There is no single amount. The label says the volume depends on the drug's concentration, dose and route, as set by that drug's maker.¹ Approved products state their own, such as 1.3 mL for each 11.6 mg Egrifta WR vial.⁶ Research peptides have no FDA label, so no volume is established for them. The reconstitution calculator shows the concentration a chosen volume gives.

Does bacteriostatic water need to be refrigerated after opening?

Not under its label. The FDA-approved label stores it at 20 to 25 °C (68 to 77 °F) and gives no refrigeration step after opening.¹ The Egrifta WR kit also keeps its bacteriostatic water at room temperature and discards it 28 days after first use.⁶ A drug mixed into the water may need refrigeration under its own label.

Written by D2C Peptides Editorial Team.

Pending qualified review.

Updated October 25, 2026.