Ancillary · 3ml/vial × 10
In plain terms: Bacteriostatic Water is the sterile fluid used to reconstitute and dilute lyophilized peptides before injection.
Bacteriostatic water is 0.9% sterile water for injection with 0.9% benzyl alcohol added as a bacteriostatic preservative. It is FDA-approved as a diluent for intramuscular and intravenous medications, with the explicit purpose of allowing a single sealed vial to be punctured multiple times over weeks without supporting microbial growth. The benzyl alcohol is what makes the difference: it inhibits the replication of common skin and environmental contaminants (Staph, Strep, Pseudomonas, Candida) at concentrations well below cytotoxic thresholds for human tissue. That is the entire reason BAC exists. Plain sterile water has no preservative, so the moment a needle goes through the stopper, bacterial counts can start climbing, and the manufacturer-rated reuse window collapses to single-use or same-day. BAC water lets a customer reconstitute a peptide vial once and pull doses out of it for 4-6+ weeks while keeping the solution sterile enough for SubQ/IM injection. For lyophilized research peptides, which are powder until you add liquid, BAC is the default diluent because nearly every common peptide stays stable in mild-acid-to-neutral aqueous solution with benzyl alcohol present, and the preservative window matches the typical 28-30 day refrigerated use cycle of a reconstituted multi-dose vial.
Typical dose ranges by experience level - educational reference. Message us and we tailor it to you.
3ml BAC kit (BW3) is the default first-order add-on. Each 3ml vial reconstitutes one peptide vial at 2ml plus has 1ml leftover, so 10 vials per kit handles a typical 10-vial peptide kit one-to-one. Customers running a single peptide kit at standard 0.5-1mg/week dosing usually don't burn through more than 1 BAC vial per peptide vial they reconstitute.
For customers running 2-4 peptides simultaneously (e.g., Reta + BPC + GHK-Cu + NAD+), a 10ml BAC kit (BW10) is the better economics. One 10ml vial reconstitutes 4-5 peptide vials at 2ml each, so a 10-vial kit covers a multi-peptide protocol for several months. BW10 is EXPRESS tier in the main catalog (not US-stock single-vial), so it adds 2-5 day delivery but kit-only at $45.
Advanced researchers running larger vials (50-100mg NAD+, 70-80mg GLOW/KLOW blends) sometimes use 3ml per reconstitution to lower the per-injection concentration and reduce sting on dense-vial draws. Same BAC volume math applies, just more BAC consumed per peptide vial. Customers running 5+ peptides should default to BW10 kits and consider stocking 2 kits at order time.
Straight talk - what people actually report, and what the studies measured.
Peer-reviewed studies and clinical guidelines - tap any to read the source.
](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2755236/) - preservative mechanism, neonate-specific caution, adult safety profile
Read study ↗PubMedPeptide stability in aqueous solution and the role of preservativesgeneral reconstitution chemistry references
Read study ↗Clinical guidelinesUSP Compounding Standards on multi-dose vial preservationbeyond-use dating for preserved diluents
Read study ↗Physician commentaryGoodRx on bacteriostatic vs sterile waterpatient-facing comparison
Read study ↗Physician commentaryEmpower Pharmacy on benzyl alcohol in compounded injectablescompounding pharmacy framing of BAC selection
Read study ↗Aggregated sentiment from public forums & socials - real-world reports, not individual endorsements.
Sting at injection site: almost always traced to the peptide, not the BAC. Switching to a non-preserved sterile water rarely changes sting, switching the injection technique (slower push, warmer vial, fattier tissue site) usually does.
Benzyl alcohol sensitivity: a small handful of customers report flushing or itching at the injection site, in those cases the move is Pfizer sterile water (single-use) or PBS water on the Members catalog.
"Cloudy BAC" concerns: pre-puncture BAC should be crystal clear, cloudiness or particulates means a contaminated or out-of-spec vial, discard. Post-mix peptide solution cloudiness is the peptide not the BAC.
KPV-specific note: small community signal that KPV does better in PBS than BAC. Not a hard rule, most customers run KPV in BAC fine, but worth knowing for the troubleshooting bucket.
- Divergence: Literature on KPV reconstitution is essentially nonexistent (the published KPV peptide work is mostly in vitro or animal). Community guidance to "use PBS for KPV" is based on a few influential peptide forum posts, not RCT data. Treat as preference-not-rule.
Route: N/A - diluent (the BAC itself isn't injected as a drug, it's the carrier for the peptide)
Injection site: N/A - once mixed with peptide, the peptide's site rules apply (SubQ abdomen/thigh, IM glute/delt, etc.)
Storage: Unopened BAC vial: room temperature, stable until printed expiration (typically 1-2 years from manufacture). Punctured BAC vial: the USP label states 28 days at room temperature after first puncture. In practice most peptide customers refrigerate after first puncture and the same 28-30 day window applies. Reconstituted peptide solution (peptide + BAC mixed): refrigerated, 4-6 weeks for most peptides, longer for highly stable ones (BPC, TB-500), shorter for fragile ones (GLP-1s past ~6 weeks lose potency).
Notes: Wipe the rubber stopper with an alcohol swab before every draw. Never remove the rubber stopper, the needle goes through it. Don't shake the vial when mixing with a peptide, swirl gently for 30-60 seconds. Inject the BAC down the inside wall of the peptide vial, not directly onto the powder, to avoid foaming/denaturation. A single 10ml BAC vial reconstitutes 3-5 standard peptide vials (at 2ml per peptide), so customers running multiple peptides don't need a BAC vial per peptide. Customers asking "do I refrigerate the BAC vial itself?" - pre-puncture, no, room temp is fine. Post-puncture, fridge is the safe call.