Sterile Water

Pharmaceutical-grade laboratory and research supply. This product listing describes general pharmacopeial quality standards for sterile water products and is not a claim of FDA approval for this specific listing. Any parenteral use should only occur under appropriate professional and prescriber oversight.

Sterile Water for Injection, sometimes labeled SWFI, is a purified, non-pyrogenic, preservative-free water product used as a solvent or diluent for reconstituting and preparing other compounds under sterile conditions. Nexa Peptide Labs sells sterile water for sale to laboratories, pharmaceutical research facilities, and institutional buyers who need a verified, pharmaceutical-grade diluent on hand.

Every peptide or lyophilized compound in a research catalog eventually needs a diluent, and the diluent matters as much as the compound itself. Sterile water that is not properly filtered, not tested for endotoxins, or not packaged for single-use ends up contaminating exactly the kind of careful protocol it was supposed to support. This page covers what sterile water actually is, how it differs from bacteriostatic water, what pharmacopeial standards apply, and what to verify before you buy from any supplier.

What Is Sterile Water for Injection?

Sterile Water for Injection is water that has been purified by distillation or reverse osmosis and packaged as a sterile, non-pyrogenic, preservative-free solution. Pharmacopeial standards for water intended for parenteral use set strict limits on particulate matter, endotoxin content, and microbial contamination, since this water is meant to carry other substances into solution without introducing anything of its own. Because it contains no preservative, a vial is intended for single use once opened; the labeling for the FDA-approved branded version of this product explicitly states it should not be administered directly without the addition of a solute, since plain water introduced into the bloodstream without an additive can cause hemolysis or electrolyte dilution.

Sterile Water Versus Bacteriostatic Water

Buyers often use the two terms interchangeably, but they are different products. Sterile Water for Injection is preservative-free and intended for single-dose use. Bacteriostatic Water for Injection contains benzyl alcohol as a preservative, typically at 0.9 to 1.1 percent, which allows a single vial to support multiple withdrawals over time. That same preservative is also why bacteriostatic water carries a specific warning against use in neonates, since benzyl alcohol has a documented association with toxicity in newborns; preservative-free sterile water is the appropriate choice whenever that consideration applies. Nexa Peptide Labs also carries bacteriostatic water (listed as Antibacterial Water) for buyers who specifically need the multi-dose, preserved version rather than single-use sterile water.

Sterile Water Specifications and Comparison

The table below compares Sterile Water for Injection against bacteriostatic water, the other diluent in the same supply category, so buyers can choose the right one for a given protocol.

Related product: bacteriostatic water (Antibacterial Water) product page.

Purity, Certificate of Analysis, and Batch Testing

Sterile water intended for parenteral or laboratory reconstitution use is manufactured under controlled, validated filtration and aseptic processing conditions, with testing for sterility, particulate matter, and pyrogen content specific to each production batch. A Certificate of Analysis specific to the production batch is available on request. Institutional buyers, CROs, and pharmaceutical R&D facilities purchasing for a funded study or documented protocol should request the COA before ordering, not after. See the Certificate of Analysis and lab testing page for sample reports and testing methodology.

Sourcing Sterile Water: What to Verify Before You Buy

Diluent quality is easy to overlook next to the compound it is meant to dissolve, but a contaminated or mislabeled diluent can undermine an otherwise well-controlled protocol. Before buying sterile water from any supplier, it is worth confirming three things. First, is the product actually preservative-free sterile water, or is it bacteriostatic water mislabeled or described loosely, since the two are not interchangeable for every use case. Second, does the Certificate of Analysis correspond to the specific batch being shipped, covering sterility and endotoxin testing, rather than a generic template reused across listings. Third, is the vial packaged and sealed for single-use integrity, since a compromised seal defeats the purpose of buying sterile water in the first place.

Storage and Handling

Store sterile water vials at controlled room temperature, protected from light, and inspect the vial for particulate matter or discoloration before use. Once a single-dose vial is opened or its seal is broken, any unused portion should be discarded rather than stored for later use, since the product contains no preservative to control microbial growth after opening. Handling should follow your institution’s standard laboratory or pharmaceutical procedures.

Buying Sterile Water From Nexa Peptide Labs

Sterile water is for sale in individual vials and bulk wholesale quantities to biotechnology laboratories, pharmaceutical manufacturing and R&D facilities, academic research institutions, contract research organizations, and international distributors. Every order ships with batch documentation, and volume pricing is available for CROs and institutional buyers purchasing on a recurring basis. See the research use policy page and the shipping and fulfillment FAQ for details.

Frequently Asked Questions

What is sterile water for injection used for?

It is used as a solvent or diluent vehicle for reconstituting and preparing other compounds under sterile conditions in laboratory, pharmaceutical, and clinical support settings. It is not intended to be administered on its own without an added solute.

What is the difference between sterile water and bacteriostatic water?

Sterile water contains no preservative and is intended for single-dose use, while bacteriostatic water contains benzyl alcohol as a preservative and is approved for multi-dose use across repeated withdrawals from the same vial. Bacteriostatic water is not appropriate for neonates because of the benzyl alcohol content.

Can sterile water be injected directly on its own?

No. Plain sterile water introduced into the bloodstream without an added solute can cause hemolysis or dangerous dilution of serum electrolytes. It is intended strictly as a diluent for use with another compound, under appropriate professional and prescriber oversight where human use is involved.

Is sterile water pyrogen-free?

Yes. Sterile water for injection is manufactured and tested as a non-pyrogenic product, meaning it is tested to be free of fever-inducing bacterial byproducts, in addition to being sterile and particulate-free.

Do you provide a Certificate of Analysis for sterile water?

Yes. Each production batch includes documentation covering sterility, particulate matter, and pyrogen testing specific to that batch, available on request before purchase.

Can I buy sterile water in bulk or wholesale quantities?

Yes. Sterile water is available in single vials and bulk wholesale quantities, with volume-based pricing for CROs, academic labs, pharmaceutical R&D facilities, and institutional buyers.

How should sterile water be stored?

Store vials at controlled room temperature, protected from light, and inspect for particulate matter or discoloration before use. Once opened, a single-dose vial should not be stored for later use since it contains no preservative.

Is this the same as the FDA-approved prescription Sterile Water for Injection product?

Sterile Water for Injection USP is an FDA-approved prescription product when marketed and dispensed as a branded pharmaceutical. This listing describes a pharmaceutical-grade laboratory and research supply product manufactured to comparable pharmacopeial quality standards; it is not a claim that this specific listing is the approved branded product, and any parenteral human use should occur only under appropriate professional and prescriber oversight.

Do you ship sterile water internationally?

Nexa Peptide Labs fulfills United States orders directly through its distribution network and supports international distributors; buyers outside the United States should confirm current import requirements in their own country before ordering.

What purity level should I expect when I buy sterile water online?

Reputable suppliers manufacture under validated aseptic processing conditions and provide a batch-specific COA covering sterility, particulate matter, and pyrogen testing. Buyers comparing vendors should request the COA before purchase rather than relying on the listing description alone.

Reviewed by , Nexa Peptide Labs Science and Quality Assurance Team.
Last updated: September 4, 2026.

Sources: Sterile Water for Injection, USP prescribing information, DailyMed. Bacteriostatic Water for Injection, USP prescribing information, DailyMed.

Research background

• Other supplies and ancillary compounds
• Choosing a diluent for laboratory reconstitution
• Certificate of analysis for this lot

Research use only. Not for human or animal consumption.