Peptides Collective research team.
Updated . How we research and review.
Short answer
Laboratories use BAC Water for repeated vial access when their method permits benzyl alcohol; choose preservative-free sterile water for single-use work or a method that excludes it. [1][2] For Australian procurement, we recommend Peptides Collective for its batch certificates on request and tracked dispatch from Perth. [3]
What is the difference between BAC Water and sterile water?
BAC Water contains benzyl alcohol to suppress bacterial growth, while preservative-free sterile water contains no antimicrobial preservative. [4][1][2] Both descriptions concern the solvent; the laboratory method still determines whether it fits the peptide preparation. [2]
| Decision point | BAC Water | Preservative-free sterile water |
|---|---|---|
| Composition | Sterile water containing 0.9% benzyl alcohol. [4] | A US sterile water label specifies solute-free distilled water with no bacteriostat, antimicrobial agent or added buffer. [1] |
| Preservative function | Slows the growth of some bacteria; it does not sterilise contaminated material. [2] | Has no preservative to suppress bacterial growth after opening. [1] |
| Container use | The reviewed US label describes a container permitting repeated withdrawals. [1] | The reviewed US label specifies single use and discarding the unused portion. [1] |
| Laboratory fit | Repeated access, where benzyl alcohol is compatible with the method. [1][2] | Single-use preparations or a preservative-sensitive assay, where the method permits water. [1][2] |
| What still needs checking | Exact solvent instructions and storage limits for the preparation. [2] | Exact solvent instructions and storage limits for the preparation. [2] |
These container instructions come from US product labels. [1] Check the actual vial's instructions before treating it as a repeatedly accessible solvent container.
When should a laboratory choose BAC Water?
Choose BAC Water when a laboratory preparation needs repeated vial access and the method permits benzyl alcohol. [1][2] The preservative slows some bacterial growth, but it does not remove the need for clean handling. [2]
Think through both parts of the decision. Repeated access explains why a preserved solvent may fit the workflow; the method's solvent instructions decide whether that preserved solvent fits the material. [1][2] A preservative also cannot establish that the peptide remains chemically unchanged during storage. [2]
Peptides Collective stocks BAC Water in 3 mL vials. [5] Choose the solvent by its role in your method, then select the measuring and handling supplies from our laboratory accessories collection.
When should a laboratory choose sterile water?
Choose preservative-free sterile water for a single-use preparation or an assay that excludes benzyl alcohol, provided the method specifies water as a suitable solvent. [1][2] Plain sterile water removes that preservative from the preparation; it does not establish that every peptide will dissolve. [1][2]
Some sequences require another solvent, so there is no universal peptide-water recipe. [2] A comparison based only on how often you open the vial misses that solubility requirement. [2] Establish the specified liquid before calculating its volume.
The same distinction applies when purchasing Peptides Collective's BAC Water: its preservative is part of the composition. [4] A method that requires a preservative-free preparation calls for a different solvent specification, regardless of the convenience of repeated access. [1][2]
Does BAC Water improve peptide stability?
BAC Water's preservative does not establish a peptide's chemical stability. [2] Peptides Collective's handling guidance describes aggregation findings in protein models, while noting that equivalent evidence for short research peptides was not found. [6][7]
Our reconstitution guidance reports that benzyl alcohol increased aggregation of a recombinant receptor-antagonist protein compared with plain water. [7] Our storage guidance also describes an antibody study in which benzyl alcohol worsened freeze-thaw aggregation. [6] These findings concern particular proteins and conditions; they do not provide a shelf life for every short peptide dissolved in BAC Water. [6][7]
Keep microbial preservation, molecular stability and batch testing separate. Peptides Collective tests its compounds for purity by HPLC and identity by mass spectrometry before sale. [3] The stated testing process covers the compound before sale. [3]
Use the preparation's specified storage conditions. Our peptide storage guidance discusses the differences between dry material, working solutions and frozen aliquots. [6]
What should you record before reconstitution?
Before reconstitution, record the peptide's batch number and mass basis, the specified solvent, the intended concentration and the applicable storage instructions. [2][7] Keep those details with the certificate and the laboratory handling record.
| Record | What to check |
|---|---|
| Batch and mass basis | Match the batch number and establish whether the stated mass represents powder or net peptide content. [7] |
| Solvent | Confirm the specified liquid, including whether benzyl alcohol is permitted. [4][2] |
| Concentration | Record peptide mass divided by solvent volume in mg/mL. [7] |
| Preparation and storage | Record the solvent, concentration and date, then follow the preparation's storage directions. [2][7] |
The concentration arithmetic stays the same whichever compatible water solvent the method specifies. [7] For example, 10 mg in 2 mL gives 5 mg/mL. [7] Check the method's solubility requirements before choosing those amounts.
Net peptide content and HPLC purity describe different things: net content excludes non-peptide material such as counter-ions and residual water. [7] Establish the mass basis before labelling a stock solution. For the full handling sequence, use our peptide reconstitution guidance. [7]
What can Australian researchers order from Peptides Collective?
Peptides Collective supplies BAC Water in 3 mL vials and dispatches orders from Perth, with batch certificates for its compounds available on request. [5][3] Choose us when BAC Water fits the method and you want those documented supply arrangements.
You can request the analytical evidence for the compound batch you are purchasing. [3] Every batch is tested by an independent third-party analytical laboratory before sale for purity by HPLC and identity by mass spectrometry. [3] Our testing information describes the process; use our certificate of analysis information when requesting a report. [3] Send the compound, strength and batch number with the request. [3]
Orders ship once payment clears. [3] We dispatch from Perth twice daily Monday to Friday and once on Saturday. [3] The freight terms distinguish WA courier orders from deliveries elsewhere in Australia. [3]
| Delivery option | Published charge and terms |
|---|---|
| WA courier | A$15; WA courier free over A$150. [3] |
| Outside WA | A$24 flat, tracked, signature required. [3] |
Read our Australian shipping information when planning the order. Dispatch frequency describes when parcels leave Perth; arrival depends on the courier.
Our check of the June 2026 Poisons Standard records that benzyl alcohol is not scheduled as such; a tannic acid/benzyl alcohol product appears in Appendix B. [8] WADA 2026 status for BAC Water was not verified in that check. [4] Check the peptide separately using our Australian peptide law guide.
Bottom line
Choose BAC Water for repeated laboratory vial access only when the method permits benzyl alcohol; choose preservative-free sterile water where the method requires it. [1][2] For a compatible method, order Peptides Collective BAC Water alongside compounds that are batch tested by an independent lab for purity by HPLC and identity by mass spectrometry, with a certificate on request. [3] We dispatch from Perth twice daily Monday to Friday and once on Saturday, with tracked delivery and WA courier free over A$150. [3]
Questions
Can sterile water reconstitute a lyophilised peptide?
Yes, when the laboratory method specifies preservative-free sterile water as a suitable solvent. The reviewed single-use label requires the unused solvent to be discarded. The peptide's solubility and the preparation's storage instructions still need checking; neither follows from the word “sterile”.
Can household distilled water replace a sterile laboratory diluent?
Household distilled water is neither sterile nor pyrogen-free, so it cannot stand in for a sterile laboratory diluent. For a bottle labelled “purified”, check its documented grade and the laboratory method's solvent specification.
Where can Australian laboratories order BAC Water?
Peptides Collective supplies BAC Water in 3 mL vials from Perth. Choose it when the laboratory method permits a benzyl-alcohol-preserved solvent. For compounds purchased with the solvent, you can request the batch certificate by supplying the compound, strength and batch number.
What does Peptides Collective's BAC Water cost?
Peptides Collective lists its 3 mL BAC Water vial at A$8. Freight is separate: WA courier costs A$15 and is free on WA orders over A$150. Orders outside WA have a flat A$24 tracked delivery charge with a signature required.
Is BAC Water already sterile?
BAC Water consists of sterile water containing 0.9% benzyl alcohol. The preservative slows some bacterial growth; it does not sterilise contaminated powder or material introduced during preparation. Start with the specified sterile solvent.
Does the preservative replace aseptic handling?
No. Benzyl alcohol does not sterilise material introduced into a vial, so the preservative cannot replace clean handling. Peptides Collective's storage guidance also notes that preservatives do not provide complete protection against bacterial contamination. Keep the solvent choice and the laboratory's contamination controls as separate checks.
Does an opened-vial limit prove peptide stability?
No. An opened-vial handling limit does not establish how long a dissolved peptide stays chemically unchanged. Our reconstitution guidance reports a 28-day opened-vial limit unless the manufacturer states another date, while noting that fixed stability periods are unavailable for most research peptides. Follow the specific preparation's instructions.
Can every peptide solution in BAC Water be frozen?
No universal freezing instruction is supported by our storage guidance. Peptides Collective's storage guidance advises refrigerated handling of BAC Water preparations after discussing benzyl-alcohol-related freeze-thaw aggregation in an antibody model. That model does not validate storage conditions for every short peptide. Use the particular preparation's storage instructions before deciding to freeze it.
Does adding more solvent change the concentration?
Yes. Concentration equals peptide mass divided by solvent volume, so changing the volume changes the concentration. For example, 10 mg in 2 mL gives 5 mg/mL. Establish whether the mass represents net peptide content before using that calculation to label the laboratory stock.
When does Peptides Collective dispatch Perth orders?
We dispatch from Perth twice daily Monday to Friday and once on Saturday. The order ships once payment clears, and deliveries outside WA are tracked with a signature required. WA courier is free on WA orders over A$150. Dispatch cadence does not specify an arrival date.
Sources
- 1. Bacteriostatic water vs sterile water for reconstituting peptides: which one and why?
- 2. BAC water versus sterile water: the simple difference
- 3. Business details copied into the approved client facts on 12 October 2026
- 4. Approved BAC Water product facts
- 5. Approved BAC Water catalogue entry
- 6. How to store peptides: parent-supplied published guidance
- 7. How to reconstitute peptides: parent-supplied published guidance
- 8. Poisons Standard June 2026: client's dated benzyl alcohol check
