BAC Water 10mL

Bacteriostatic water is sterile water for injection containing 0.9% benzyl alcohol as a preservative. It is the standard diluent for reconstituting lyophilised peptides in laboratory research. The benzyl alcohol inhibits bacterial growth, making the vial safe for multiple uses without contamination between withdrawals. This is critical in research settings where a single peptide vial may be accessed multiple times over days or weeks. Do not use regular water, distilled water, or saline — these lack the preservative and cannot safely support multi-use access. One 10mL vial is sufficient for reconstituting multiple peptide vials.

The volume of BAC water determines your working concentration. Common ratios: 1mL BAC water into a 10mg peptide vial = 10mg/mL (10,000 mcg/mL); 2mL into 10mg = 5mg/mL; 5mL into 10mg = 2mg/mL. For a 50mg peptide vial: 5mL BAC water = 10mg/mL. Choose your volume based on the concentration your research protocol requires. One 10mL vial of BAC water can reconstitute multiple peptide vials. See our Reconstitution Guide blog post for a full concentration table covering all our products.

Unopened BAC water can be stored at room temperature (15–25°C), protected from light. Once opened (first needle puncture), refrigerate at 2–8°C and use within 28 days — this is the standard multi-dose vial usage period for bacteriostatic preparations. The benzyl alcohol preservative maintains sterility within this window. Do not freeze BAC water. Always use a new sterile needle each time you access the vial to prevent introducing contamination that could overwhelm the preservative.

Pharmaceutical-grade bacteriostatic water for injection (USP/BP specification) has a pH range of approximately 4.5–7.0, with most preparations falling between 5.0 and 6.0. The slightly acidic pH helps maintain the solubility of benzyl alcohol and is compatible with the pH stability range of most research peptides. If your peptide research protocol requires a specific pH reconstitution buffer (e.g., pH 7.4 PBS), the BAC water can serve as an initial diluent, with subsequent buffering performed during dilution steps. For most lyophilised peptide reconstitutions, the pH of BAC water is appropriate.

BAC water is compatible with the vast majority of lyophilised research peptides including all products in our catalogue — Retatrutide (/products/retatrutide-10mg), BPC-157 (/products/bpc-157-10mg), GHK-Cu (/products/ghk-cu-50mg), Semax (/products/semax-10mg), Melanotan I (/products/melanotan-i-10mg), Melanotan II (/products/melanotan-ii-10mg), NAD+ (/products/nad-plus-100mg), and all blends. Exceptions to consider: some enzyme assays require benzyl-alcohol-free diluents as benzyl alcohol may inhibit certain enzyme classes at high concentrations — in these cases, use sterile water for injection and fresh-prepare as needed. For routine peptide reconstitution, BAC water is the standard choice.

Benzyl alcohol (C₇H₈O) is a bacteriostatic agent — it inhibits bacterial growth rather than killing all organisms (which would make it bactericidal). At 0.9% w/v concentration (9mg/mL), benzyl alcohol disrupts bacterial cell membrane integrity sufficiently to prevent proliferation in the aqueous solution. This concentration has been established through decades of pharmaceutical use as effective, stable, and compatible with injection-grade water. It does not precipitate at refrigerator temperatures and remains active throughout the 28-day post-opening period. The 0.9% concentration is sub-cytotoxic for most mammalian cell types at the dilutions typical in peptide reconstitution.

Yes — the critical difference is the preservative. Sterile water for injection (SWFI) contains only water, sterilised and sealed under aseptic conditions — no benzyl alcohol or other preservatives. Once the vial seal is punctured, SWFI must be used immediately or discarded, as it has no defence against microbial contamination from repeat needle access. BAC water contains 0.9% benzyl alcohol, which maintains bacteriostasis for 28 days post-opening. For research protocols requiring multiple withdrawals over days or weeks, BAC water is the appropriate choice. SWFI is appropriate only for single-use reconstitutions where the entire vial contents are used immediately.

Yes — this is the primary advantage of bacteriostatic water over sterile water for injection. The 0.9% benzyl alcohol preservative allows the vial to be accessed multiple times with a sterile needle over the 28-day post-opening period while maintaining bacteriostatic conditions. Each withdrawal must be made with a fresh, sterile 31G needle (available at /products/insulin-needles-31g) — never reuse a needle that has been used elsewhere, as this is the primary route by which contamination would be introduced. The vial septum is designed to reseal after each needle withdrawal.

Unopened BAC water vials have a typical shelf life of 2–3 years from manufacture date when stored at room temperature (15–25°C), protected from direct light. The expiry date is printed on each vial. Our stock is managed on a first-in, first-out basis to ensure adequate remaining shelf life on all dispatched vials. Once opened, the effective use period is 28 days (refrigerated). If you are ordering for future research protocols, the sealed shelf life provides ample time for advance purchasing.

A single 10mL BAC water vial is sufficient for reconstituting multiple peptide vials. Typical usage: 1–2mL per 10mg peptide vial; 2–5mL per 50mg peptide vial. For the Retatrutide Research Bundle (2x 10mg vials), you need 2–4mL total — well within the 10mL supply. For a research programme involving 4–5 standard 10mg peptide vials, one BAC water vial is sufficient. Only purchase additional BAC water if your protocol requires unusually high dilution volumes or if you are running multiple 50mg vial preparations simultaneously. BAC water is also included in the Retatrutide Bundle at /products/retatrutide-bundle.

Our BAC Water 10mL is sourced from pharmaceutical-grade manufacturing facilities producing to USP (United States Pharmacopeia) and/or BP (British Pharmacopoeia) specifications for bacteriostatic water for injection. Quality testing includes: sterility testing (no microbial growth), pH verification (4.5–7.0 range), benzyl alcohol concentration verification (0.9% w/v), endotoxin testing (LAL), and particulate matter assessment. The vials are sealed under aseptic conditions in a clean-room environment. Full documentation is available on request.

Using tap water, distilled water, or non-sterile water for peptide reconstitution introduces several problems: microbial contamination risk — non-sterile water contains bacteria that will proliferate in the peptide solution within hours; dissolved minerals and impurities in tap water can react with peptides, causing aggregation or degradation; no bacteriostatic preservation means the reconstituted peptide cannot be safely stored and re-accessed over days or weeks; and contaminated peptide solutions are unsuitable for any legitimate research use. Always use pharmaceutical-grade BAC water (for multi-use protocols) or sterile water for injection (for single-use only). Our BAC Water 10mL is specifically supplied for this purpose.