30ml Bac Water: What It Is and How It's Used

30ml bac water is a 30-milliliter vial of bacteriostatic water, which is sterile water mixed with 0.9% benzyl alcohol. The preservative allows the same vial to be entered with a needle more than once, so it is commonly used to reconstitute freeze-dried peptide powders that will be drawn from over several days or weeks. In the United States it is sold as a prescription product, and it is not the same thing as plain sterile water or normal saline.

What Is 30ml Bac Water Made Of?

Bacteriostatic water is a simple product, and that simplicity is a big part of why it shows up in clinics, compounding pharmacies, and research labs.

• Sterile water — the base diluent.
• Benzyl alcohol 0.9% — a preservative that inhibits bacterial growth.
• No added salts or buffers — unlike normal saline, it contains no sodium chloride.

Bacteriostatic water contains 0.9% benzyl alcohol, which is what separates it from single-use sterile water. That preservative is the reason a multi-dose vial can be punctured repeatedly instead of being discarded after one draw.

How 30ml Bac Water Is Used for Reconstitution

Reconstitution means adding liquid to a lyophilized powder so it can be measured and drawn into a syringe. Most people treat a 30 mL vial as a stock supply and pull only the volume they need for each small powder vial.

1. Wipe the rubber stoppers of both vials with an alcohol swab and let them dry.
2. Draw air into the syringe equal to the volume of water you plan to add.
3. Inject that air into the water vial, then withdraw the water.
4. Aim the stream at the inside wall of the powder vial rather than directly at the powder.
5. Swirl gently — do not shake — until the powder dissolves completely.
6. Refrigerate the reconstituted vial and write the date on the label.

Typical reconstitution volumes run from about 1 mL to 3 mL per small powder vial, so one 30 mL bottle can serve many of them. Anyone using bac water for peptides should follow the mixing and storage instructions that come with that specific product.

Powder vial size	Bac water added	Resulting concentration
5 mg	2 mL	2.5 mg/mL
10 mg	2 mL	5 mg/mL
10 mg	5 mL	2 mg/mL

Those figures are arithmetic examples only, not dosing guidance. A licensed healthcare professional should set any actual dose.

30ml vs 10ml Bac Water: Which Size Fits Your Use?

The practical difference between sizes is how often you reconstitute and how quickly you move through a vial. The bac water 30ml hospira presentation, manufactured by Hospira, is one of the most widely distributed versions sold in the US.

Vial size	Best for	Use after first puncture	Typical US price
10 mL	Occasional use, one or two powder vials	About 28 days refrigerated	$5–$15
30 mL	Frequent reconstitution, several powder vials	About 28 days refrigerated	$10–$25
30 mL case (25 vials)	Clinics, pharmacies, labs	Until expiry if unopened	$150–$300

A 30 mL vial of bacteriostatic water expires roughly 28 days after the first puncture, even if it is still mostly full. Someone who reconstitutes only once or twice a year will usually waste less product with a smaller bottle such as bac water 10ml.

Storage, Safety, and Legal Status

• Store unopened vials at controlled room temperature, between 20°C and 25°C (68°F to 77°F). Do not freeze.
• Refrigerate after the first puncture and keep the vial capped between draws.
• Discard the vial if the solution looks cloudy, discolored, or contains particles.
• Benzyl alcohol has been linked to serious adverse reactions in premature infants, so these products are not for neonatal use.
• In the United States, products labeled bac water for injection, USP are prescription (Rx) items.

Bacteriostatic water is a diluent, not a drug, and it is not FDA-approved to treat any condition on its own. Poor sterile technique or reused needles introduce genuine infection risk, no matter how clean the water is. Anyone self-administering a compound mixed with bacteriostatic water should do so with guidance from a licensed healthcare professional.

Where to Buy 30ml Bac Water

In the US, bacteriostatic water is normally obtained through a pharmacy, a medical supplier, or a licensed distributor, and most legitimate sellers ask for a prescription or a verified professional account. Hospital and compounding pharmacies are often the fastest local option.

When people search where to buy bac water online, they frequently encounter research chemical vendors selling it with a "not for human use" label. Those listings sit in a gray legal area, and sterility and authenticity are not guaranteed. Check your state's rules first, and avoid any listing that lacks a manufacturer name, lot number, or expiration date.

Price per milliliter drops sharply as vial size increases, but shelf life after opening does not change. A larger bottle is only economical if you will actually use it within about four weeks of the first puncture.

Quick Recap

• 30ml bac water is sterile water plus 0.9% benzyl alcohol.
• The preservative makes multi-dose use possible for roughly 28 days after opening.
• The 30 mL size suits frequent reconstitution; 10 mL suits occasional use.
• Bacteriostatic water is a prescription diluent in the US, not an FDA-approved treatment.

COMMON QUESTIONS

Frequently Asked Questions

What is 30ml bac water used for?

A 30 mL vial of bacteriostatic water is used as a diluent to dissolve lyophilized peptide or protein powders and to reconstitute other injectables labeled for multi-dose use. The 0.9% benzyl alcohol preservative lets the same vial be punctured several times over about 28 days. It is not a medication itself and does not treat any medical condition.

How long does 30ml bac water last?

Unopened and stored at controlled room temperature, a 30 mL vial is good until the expiration date printed on the label. After the first puncture, standard guidance is to discard it about 28 days later, even if it has been refrigerated. Throw it out sooner if the solution turns cloudy, changes color, or contains particles.

Can you buy 30ml bac water without a prescription?

In the US, bacteriostatic water for injection, USP is labeled as a prescription product, so most pharmacies require a prescription or a professional account. Some online research chemical suppliers sell it without one under a "not for human use" label, but sterility and authenticity are not guaranteed. Check your state's rules before ordering.