Where to buy Bacteriostatic Water: sizes, price per mg and how to verify the lot

What "bacteriostatic water" names, and what it does not

Bacteriostatic water, BAC water in every listing, is sterile water with benzyl alcohol added at 0.9% w/v. The benzyl alcohol is a preservative: it does not sterilise, it slows the growth of bacteria that get into a vial once the stopper has been punctured, which is the only reason to choose it over plain sterile water. It is not a peptide and not an active compound; PubChem lists the preservative, benzyl alcohol, as CID 244 at 108.1 Da, and the water is water. LabFirst sells it in 3 mL and 10 mL vials as laboratory diluent, and this page describes it as that and nothing else.

The buying problem with a diluent is the opposite of the buying problem with a peptide. There is no molecule to identify and no purity to argue about; there is a preservative that is either at strength or not, a sterility claim that is either tested or not, an endotoxin result that is either on the certificate or not, and a vial that is either made in a licensed sterile facility or filled somewhere else. Peptide resellers do not make bacteriostatic water. They buy it, and the certificate that matters is the manufacturer's, for that manufacturer's lot.

The other thing to know is that the preservative is a chemical with a shelf life and a temperature range of its own. Bacteriostatic water is stored at controlled room temperature, not refrigerated and never frozen, which is the reverse of every peptide on this site; a cold-chain box is the wrong place for it, and a vial that has been frozen may have lost its seal integrity. This page covers the diluent as laboratory material only, and nothing here describes preparing, combining or administering any substance.

The reference point for identity is public. PubChem lists Benzyl alcohol (the preservative; the diluent itself is water) as CID 244 with molecular formula C7H8O, an average molecular weight of 108.14 Da and a monoisotopic mass of 108.058 Da. Those are the numbers a mass spectrometer is checked against, and the number a certificate must print beside the observed mass.

In plain terms: Bacteriostatic water: sterile water with benzyl alcohol added to hold back bacterial growth. Not a peptide and not an active compound. This record covers the diluent as laboratory material only. Nothing here describes preparing, combining or administering any substance, and a diluent being in the catalogue implies no such use.

BAC Water for sale: sizes and price per mg

LabFirst lists BAC Water in 2 sizes (3ml, 10ml) from $12 to $15, priced per vial with the per-mg figure beside it so sizes can be compared without arithmetic. Per mg, the 10ml vial is the cheapest at $1.50 and the 3ml the dearest at $4, which is the usual shape: the vial, stopper, seal, fill and laboratory run cost the same whatever mass goes in.

The volume tiers are per size, not per basket: ten vials of one size take 10% off that line and twenty take 15%, and mixed sizes do not combine. Shipping is a flat $15 on orders under $200 and free from $200, within the United States only, with same-day dispatch on orders placed before 12 PM Pacific on a business day. The cost per mg tool runs the same comparison across any two listings, ours or anyone else's.

Bacteriostatic water is a commodity: it costs a few dollars a vial from any licensed manufacturer, and the 10 mL vial costs only a little more than the 3 mL one because the vial, the stopper and the sterile fill are the cost and the water is not. Per millilitre the 10 mL vial is far cheaper, and a laboratory that uses diluent regularly buys it; the 3 mL vial exists for work where a punctured vial should not sit around, since a smaller vial is used up before the preservative's limit on repeated puncture matters.

The price signal is the source. A vial with a manufacturer's lot and certificate costs what it costs; a vial with a reseller's template certificate and no manufacturer named may be the same water or may be something filled elsewhere, and the price will not say which. It is also the item most often used to pad a peptide order to the free-shipping line, which is a fair use of it as long as the certificate is read once. LabFirst's water is priced at the vial, the volume tiers apply, and the lot on the vial is whatever the certificate index says on the day.

The certificate a BAC Water lot must carry

A certificate of analysis for BAC Water is only complete when it carries the tests that matter for a diluent, for the exact lot on the vial. For a diluent the questions are different: not "which molecule" but "is the preservative at strength, is it sterile, and is it clean". A BAC Water certificate carries a benzyl alcohol assay against the nominal 0.9% w/v by gas or liquid chromatography, a sterility result, a bacterial endotoxins result, a pH, and a fill volume; the water itself has no mass to confirm.

Each of those figures is only interpretable with its method beside it and a date, which is what ICH Q2(R2) means when it asks that an analytical procedure be shown fit for its purpose; a "sterile" with no test named and no date is a word somebody typed. The fill volume is the net content line for a liquid: the 3ml or 10ml on the label, measured, with the overfill stated.

The benzyl alcohol assay is the line that makes the product what it says it is: a result against the nominal 0.9% w/v, by gas or liquid chromatography, with the method and the date. Plain sterile water in an identical vial reads zero on that test and is a different product with a different purpose. Sterility is a test result, by a named pharmacopoeial method, not the word on the label; bacterial endotoxins are a measured value against a stated limit; pH is a number, typically mildly acidic for this product; and particulate matter is checked because a clear liquid can still carry it. The manufacturer's name, the manufacturer's lot and the expiry date belong on the same page.

A reseller's own certificate for bacteriostatic water is worth reading for exactly one thing: whether it is the manufacturer's certificate passed through, with that manufacturer's lot matching the vial in hand, or a reseller's template with a purity percentage on it. Water does not have a purity percentage. A certificate that gives one has been written for a peptide and relabelled, and it tells you the seller has not looked at what they are shipping. LabFirst's water lots carry the manufacturer's certificate and are not sent to the peptide laboratory, because there is nothing in them for that laboratory to identify.

Where to buy BAC Water: five checks before you order from anyone

Every seller of bacteriostatic water says "third-party tested". The phrase costs nothing. These five checks take about four minutes per listing and separate a tested lot from a tested-sounding one.

1. The lot on the vial is the lot on the certificate. Read the printed lot number, then open the certificate and match it. A certificate for "BAC Water" with no lot, or a lot that does not match, describes some other vial.
2. The manufacturer is named and the certificate is theirs. A diluent is made in a licensed sterile facility, not by a peptide reseller; the certificate should name that facility and carry its own lot, and a reseller's certificate that names nobody has not shown you where the water came from.
3. The benzyl alcohol assay is printed. The preservative is the product. A result against the nominal 0.9% w/v, with the method and date, is what separates BAC Water from plain sterile water in an identical vial.
4. Sterility and endotoxins are results, not words. "Sterile" on a label is a claim; a sterility test and a bacterial endotoxins test on the certificate, each with a method and a date, are measurements.
5. The fill volume and the stopper are stated. 3ml and 10ml are nominal fills; the certificate gives the measured fill, and the vial should have a stopper rated for repeated puncture, since that is how a diluent is used.

How listings for BAC Water specifically mislead:

• A purity percentage on a water certificate. Water has no purity figure; a certificate that gives one was written for a peptide and relabelled, and the seller has not read what they ship.
• No manufacturer named. Peptide resellers do not make sterile diluent; a vial with no licensed manufacturer and no manufacturer's lot on its certificate has no known origin.
• "Sterile" as a label word with no sterility or endotoxin result. Both are tests with methods and dates; the word alone is a claim about a vial nobody examined.
• Bacteriostatic water shipped cold-chain or stored refrigerated beside peptides. It is a room-temperature product, and freezing it can compromise the seal; the storage line on its certificate says so.

How to verify a LabFirst BAC Water lot

The BAC Water sizes in stock today carry lots PO-1001-WA3 and PO-1001-WA10. Until the report is attached the product page says "pending verification" against that lot and makes no purity claim; the price stands and the report goes live the day it arrives, on the page, at /coa/, and inside the receipt and packing slip for every order of that lot.

Verification runs through the laboratory, not through us. Open the certificate index, find the lot, and use the accession number on the Freedom Diagnostics lookup page; the report you see there is the laboratory's copy, not ours. Each lot also carries a Finnrick verify link, and every receipt and packing slip states that a customer may submit a sealed vial to Finnrick's free testing programme with the order as proof of purchase, so the brand's public record is built from vials we did not choose.

The product page reads the live stock feed on load (stock, lot and certificate state for every size), so what you see when you order is what ships. The lot is printed on the label and encoded in the QR patch on its right-hand side; scanning it opens that lot's record.

Storage and shipping for BAC Water

Bacteriostatic water is kept at controlled room temperature, roughly 20 to 25 C, out of direct light, and never frozen; cold does it no good and freezing can compromise the seal and the stopper. Once the stopper has been punctured the vial is dated, because the preservative limits bacterial growth for a bounded period rather than indefinitely, and the label convention for this product is to discard a punctured vial after 28 days. A laboratory keeps that date in its own record beside the lot. The stopper is rated for repeated puncture but not for careless technique: a vial whose stopper has been cored, or that has been left open, is not bacteriostatic anything and goes in the bin.

Orders ship within the United States, flat $15 under $200 and free above it, same day when placed before 12 PM Pacific on a business day, and the shipping page states the cutoff, the carriers and what is and is not promised.

The record a laboratory keeps on arrival is what makes the certificate usable later, and it is short:

• the lot number as printed on the vial, and the certificate's accession or search code beside it;
• the date received and the condition of the seal;
• the storage location and temperature it went into;
• the number of vials, and later the date each one was opened and by whom.

A BAC Water vial with that record behind it can be traced from the bench to the laboratory report in one step; without it, the certificate is a document about a vial that can no longer be identified.

Regulatory status, and what this page is not

Bacteriostatic water is a pharmacopoeial diluent: the United States Pharmacopeia carries a monograph for it, and licensed manufacturers make it under that standard and under drug manufacturing rules, which is why the manufacturer's certificate, not a reseller's, is the document that matters. None of that is a claim about any use. What LabFirst sells is the manufacturer's product as laboratory diluent, offered as laboratory material only; a diluent being in a research catalogue implies nothing about preparing, combining or administering any substance, and nothing on this page or on the product page describes doing so.

FOR LABORATORY AND IN-VITRO RESEARCH USE ONLY. NOT FOR HUMAN OR ANIMAL CONSUMPTION. LabFirst sells BAC Water to laboratories and researchers as material for in-vitro work, gives no guidance on use, and ships only against that understanding. Nothing on this page or on the product page describes preparing or administering anything.

What is BAC Water studied for?

Published research on BAC Water investigates the areas below — which is a different question from what BAC Water will do for anyone, a claim about a living system that nothing on this site is sold for.

What it is. Bacteriostatic water: sterile water with benzyl alcohol added to hold back bacterial growth. Not a peptide and not an active compound.

What the research looks at. A laboratory diluent rather than a subject of research. What matters here is that it is a solvent, and what a solvent is made of affects the stability of whatever gets dissolved in it.

How it is thought to work. The benzyl alcohol stops bacteria multiplying, which is what separates bacteriostatic water from plain sterile water and is why a sealed multi-use container can be entered more than once under laboratory conditions.

What is not established. This record covers the diluent as laboratory material only. Nothing here describes preparing, combining or administering any substance, and a diluent being in the catalogue implies no such use.

The full record, including the certificate for the lot in stock, is on the BAC Water product page.

Common questions

Sources

• PubChem, Benzyl alcohol (the preservative; the diluent itself is water), CID 244. Public record for the molecular formula (C7H8O), average molecular weight (108.14 Da) and monoisotopic mass (108.058 Da) quoted here as the identity reference.
• DailyMed, bacteriostatic water product listings. The National Library of Medicine's index of manufacturer labels for bacteriostatic water; the storage range, the preservative strength and the puncture convention quoted here are read from those labels.
• ICH Q2(R2), Validation of Analytical Procedures (2023) 2023-11. Why a purity figure is only interpretable with its method, and what "fit for purpose" means for the HPLC and mass spectrometry results a certificate reports.
• Freedom Diagnostics, certificate lookup by accession number. The laboratory-side lookup a LabFirst lot is verified on; the report there is the laboratory copy, not ours.
• Finnrick, verify a vendor or lot. Independent verification page linked from every LabFirst lot; customers may submit sealed vials with their order as proof of purchase.