[ Laboratory preparation ]
Peptide reconstitution calculator: how much bac water per vial
Enter the peptide mass in the vial and the volume of bacteriostatic water you are adding. The calculator returns the working-stock concentration in mg/mL and mcg/mL, and, if you want it, the volume of that stock which contains a given mass of peptide. Free, no account, and nothing you type leaves your browser.
Laboratory preparation maths only. Not a dosing calculator, and no human-use guidance is given or implied.
[ Research use only · Not for human consumption ]
[ Interactive tool ]
Reconstitution concentration calculator
Enter the peptide mass in the vial and the volume of bacteriostatic water you are adding to read off the working-stock concentration. Optionally, enter a target amount to see the volume of stock that contains it. Laboratory working-stock math only.
[ Working-stock concentration ]
5 mg/mL
= 5000 mcg/mL
A laboratory reconstitution-concentration tool for preparing research working stocks. It is not a dosing calculator and gives no human-use guidance. Supplied for in-vitro / laboratory research use only.
How much bac water per vial: the quick reference
Working-stock concentration is the peptide mass in the vial divided by the volume of bacteriostatic water added. Every figure below is that division, in mg/mL. A 10 mg vial in 2 mL of bac water is 5 mg/mL; the same vial in 5 mL is 2 mg/mL.
| Vial | + 1 mL bac water | + 2 mL bac water | + 3 mL bac water | + 5 mL bac water |
|---|---|---|---|---|
| 5 mg | 5 mg/mL | 2.5 mg/mL | 1.667 mg/mL | 1 mg/mL |
| 10 mg | 10 mg/mL | 5 mg/mL | 3.333 mg/mL | 2 mg/mL |
| 15 mg | 15 mg/mL | 7.5 mg/mL | 5 mg/mL | 3 mg/mL |
| 20 mg | 20 mg/mL | 10 mg/mL | 6.667 mg/mL | 4 mg/mL |
| 30 mg | 30 mg/mL | 15 mg/mL | 10 mg/mL | 6 mg/mL |
| 50 mg | 50 mg/mL | 25 mg/mL | 16.67 mg/mL | 10 mg/mL |
The vial masses above are the sizes the catalogue ships in, from a 5 mg BPC-157 vial through to a 30 mg retatrutide vial and the 50 mg GHK-Cu vial. Use the preset selector in the calculator to load any of them exactly.
Why bacteriostatic water is the diluent
Bac water is sterile water with 0.9% benzyl alcohol added as a preservative. Plain sterile water stops being sterile the moment a needle goes into it, whereas the benzyl alcohol in bacteriostatic water holds bacterial growth down, so one vial can be drawn from repeatedly across a multi-step protocol. That multi draw window is the reason this, and not plain water, is the diluent named in the reconstitution section of every freeze-dried compound in the catalogue. Bacteriostatic water is stocked in 3 ml and 10 ml vials: the 3 ml suits a single compound, the 10 ml suits a bench working through several.
Adding the water
Draw the volume you calculated into a sterile transfer syringe using standard aseptic technique, then add it slowly down the inside wall of the lyophilised vial and swirl gently. Do not shake: shaking shears the peptide and can denature it. Let the powder dissolve fully before use, and record the concentration you prepared against the batch number on the label. The full reconstitution guide covers the method, storage and handling in depth.
[ Frequently asked ]
Reconstitution maths, answered.
- How much bacteriostatic water do you add to a peptide vial?
- There is no single correct volume. The volume you add sets the working-stock concentration, so it follows from the concentration your research protocol calls for: less bac water gives a more concentrated stock, more gives a more dilute one. A common convenience is to pick a round number, for example reconstituting a 10 mg vial in 2 mL to get a 5 mg/mL stock. Use the calculator on this page to test a few volumes and read off the result.
- How much bac water for a 20 mg vial?
- 20 mg in 1 mL gives a 20 mg/mL working stock, 20 mg in 2 mL gives 10 mg/mL, and 20 mg in 4 mL gives 5 mg/mL. The same arithmetic applies to any vial mass: concentration equals the peptide mass in the vial divided by the volume of bacteriostatic water added. The reference table on this page lists the common combinations.
- Is this a dosing calculator?
- No. It is not a dosing calculator. It is a reconstitution-concentration tool for preparing laboratory working stocks: it computes mg/mL and mcg/mL concentration, and the volume of that stock which contains a stated mass of peptide. It carries no human-use semantics, and all products are supplied for in-vitro and laboratory research use only.
- What is bac water?
- Bac water is the shorthand for bacteriostatic water: sterile water with 0.9% benzyl alcohol added as a preservative. It is the standard diluent used to bring a freeze-dried research peptide back into solution, and it is what the volume field on this calculator refers to.
- Why bacteriostatic water rather than sterile water?
- The 0.9% benzyl alcohol holds microbial growth down, so the same vial can be drawn from across a multi-step research protocol. Plain sterile water loses its sterility guarantee the moment it is first accessed, which is why bacteriostatic water is the diluent named across peptide-research methodology.
- Does the calculator work for blends like GLOW70 and KLOW80?
- Yes, one component at a time. A blend vial holds several peptides at different masses, so enter the mass of the component you are working with and the total volume of bacteriostatic water added to the vial. The result is that component's concentration in the reconstituted stock.
- Where can I buy bacteriostatic water in Australia?
- Bacteriostatic water is stocked here in 3 ml and 10 ml vials, dispatched AU-domestic with AUD pricing and free shipping over $100. It is supplied for in-vitro and laboratory research use only.
[ What you need next ]
Related
- Bacteriostatic water — 3ml / 10mlThe bac water this calculator assumes you are adding. AU-domestic dispatch, AUD pricing.
- Peptide reconstitution guideThe long-form method: aseptic transfer, swirling, storage and handling after reconstitution.
- All research peptidesEvery compound in the catalogue, each with its batch certificate on file.
- Research-peptide glossaryLyophilised, working stock, bacteriostatic, HPLC and the rest of the vocabulary.
Elite AU Peptides supplies research peptides and related compounds for laboratory and in-vitro research use only. Products are not therapeutic goods, are not TGA-approved, and are not for human or animal consumption. Nothing on this site constitutes medical advice or a therapeutic claim. Purchasers must be 18 years or older and are responsible for complying with all applicable laws in their jurisdiction.