Reconstituting a peptide means adding bacteriostatic water to a vial of freeze-dried powder. The amount of peptide never changes — only how concentrated it is. This works out the concentration, what volume holds a given amount, and where that lands on a 100-unit syringe.
The working. BPC-157 10MG holds 10,000mcg. Divided by 2mL of water that is 5,000mcg per mL, so 250mcg sits in 0.05mL — 5 units on a 100-unit syringe. Adding more water does not change how much peptide is in the vial.
BPC-157 10MG — $75 →A vial holds a fixed mass of peptide — a 10mg vial holds 10mg, or 10,000 micrograms, whether you add 1mL of water or 5mL. What the water changes is concentration: 10mg in 1mL is 10mg/mL, and the same vial in 2mL is 5mg/mL. A smaller volume of water means a smaller volume per draw, which is harder to measure accurately on a syringe; a larger volume is easier to measure but empties the vial in fewer millilitres.
Units come from the syringe, not the peptide. A 100-unit insulin syringe holds 1mL, so one unit is 0.01mL. That is why the same 250mcg draw is 5 units at one concentration and 10 at another — the peptide is identical, the marking is not.
| Vial | +1mL | +2mL | +3mL | +5mL |
|---|---|---|---|---|
| 2mg | 2 mg/mL | 1 mg/mL | 0.67 mg/mL | 0.4 mg/mL |
| 5mg | 5 mg/mL | 2.5 mg/mL | 1.67 mg/mL | 1 mg/mL |
| 10mg | 10 mg/mL | 5 mg/mL | 3.33 mg/mL | 2 mg/mL |
| 15mg | 15 mg/mL | 7.5 mg/mL | 5 mg/mL | 3 mg/mL |
| 20mg | 20 mg/mL | 10 mg/mL | 6.67 mg/mL | 4 mg/mL |
| 30mg | 30 mg/mL | 15 mg/mL | 10 mg/mL | 6 mg/mL |
This calculator does arithmetic on a vial. It is not dosing guidance. OzPeptides products are sold for research and laboratory use only, not for human consumption. 18+ only.
A lyophilised peptide is a freeze-dried solid. Reconstitution is dissolving that solid in a liquid so it can be measured and drawn accurately — nothing is added to the peptide and nothing is created. The vial holds the same quantity before and after, and the only thing the water decides is how much liquid that quantity is spread through.
That single fact resolves most of the confusion around the topic. There is no correct volume of bacteriostatic water for a given vial, because volume sets concentration rather than dose. What a chosen volume does decide is how large each draw has to be, and therefore how precisely it can be measured on the syringe in front of you.
The freeze-dried cake in the vial often looks like very little, and sometimes it is barely visible at all. That is normal: a few milligrams of peptide occupies almost no space once the water is removed, and appearance tells you nothing useful about whether the vial is correctly filled. The certificate does.
The practical rule is to pick a volume that puts a typical draw somewhere in the middle of the syringe rather than at either extreme. A draw of one or two units is hard to measure accurately, because the error in reading the barrel is a large fraction of a small number. A draw of eighty units is fine to measure and empties the vial quickly.
Round numbers help more than they look. Reconstituting a 10MG vial in 2ML gives 5MG/ML, which makes 500mcg exactly 0.1ML and exactly ten units on a 100-unit syringe. The same vial in 1.7ML gives arithmetic nobody wants to do twice. Choosing a volume that produces clean figures removes an entire category of error.
Vial capacity is the other constraint. Most peptide vials are 2ML or 3ML and cannot hold more than that, so the upper end of the range is set by the glass rather than by preference.
A standard U-100 insulin syringe holds 1ML in 100 marked units, so one unit is 0.01ML. That conversion is fixed and it is where most arithmetic errors begin, because the syringe is marked in units of insulin rather than in volume, and a peptide has nothing to do with insulin.
Working in millilitres first and converting at the end avoids the problem. Divide the amount you want by the concentration to get a volume in millilitres, then multiply by 100 to get units. At 5MG/ML, 250mcg is 0.05ML, which is 5 units. At 10MG/ML the same 250mcg is 0.025ML, which is 2.5 units — and a half-unit reading on a syringe marked in whole units is a good sign the concentration was chosen badly.
Syringes also come in 0.3ML, 0.5ML and 1ML barrels. A 0.3ML barrel is still marked 1 to 30 in the same units, so the conversion does not change; only the maximum volume does.
Bacteriostatic water is water with 0.9% benzyl alcohol added. The benzyl alcohol inhibits bacterial growth, which is what allows a vial to be entered repeatedly over weeks rather than once. Sterile water contains no preservative: it is sterile at the moment it is opened and offers nothing against contamination introduced afterwards.
That difference is the reason bacteriostatic water is the default for any multi-draw vial, and the reason a vial reconstituted with sterile water should be treated as single-use. It is also a real cost difference over time, since a vial that cannot be stored is a vial that has to be used or wasted.
A small number of peptides are supplied with a recommendation for a different diluent, and a few compounds are sensitive enough to pH that the choice matters chemically rather than just microbiologically. Those are exceptions; bacteriostatic water is the general answer.
For most lyophilised peptides the useful window after reconstitution with bacteriostatic water, kept refrigerated and out of light, is measured in weeks rather than days or months. Dry and cold, the same peptide is stable for far longer — which is why they are supplied freeze-dried and why mixing early rather than when needed is a waste of shelf life.
Some compounds are shorter-lived in solution than the general rule. NAD+ hydrolyses in water at a rate that rises with pH and temperature. Glutathione oxidises on exposure to air and light, and the oxidised form is not the active one. Oxytocin carries a disulfide bridge that can be reduced or scrambled. Each of those guides says so on its own page.
Freezing a reconstituted vial is not an improvement. Freeze-thaw cycles denature peptides, and the benzyl alcohol that protects a refrigerated vial does nothing for one that has been frozen and thawed.
Direct the diluent down the inside wall of the vial rather than straight onto the cake, and let it dissolve rather than forcing it. Swirl gently; never shake. Foaming is the visible sign of denatured peptide, and a peptide that has foamed has lost some fraction of what was in the vial with no way to tell how much.
Let the cake dissolve fully before drawing. Undissolved material means the concentration in the liquid is lower than the calculation assumes, and the first draws will be weaker than the last. A few minutes at room temperature usually finishes what swirling starts.
Wipe the stopper with alcohol before each entry and use a fresh needle each time. Bacteriostatic water inhibits growth; it does not sterilise, and it will not rescue a vial that has been repeatedly entered with a used needle.
This tool converts between vial strength, diluent volume, concentration and syringe units. That is arithmetic, and arithmetic is all it is. It does not recommend an amount to draw, and no page on this site does, because these are laboratory research compounds and dosing guidance is outside what a supplier of research materials should offer.
Every compound in the catalogue is supplied for in-vitro and laboratory research only, to buyers aged 18 and over, and none of them is registered in Australia except where a guide says otherwise about a registered medicine of the same molecule.
What the calculator is genuinely useful for is catching errors: a draw that lands on an awkward fraction of a unit, a concentration that leaves a vial with two doses in it, or a number that turns out to be ten times what was intended. Those are the mistakes worth designing out, and they are visible the moment the arithmetic is written down.
There is no single correct amount — it sets the concentration, not the quantity of peptide. A 10mg vial reconstituted with 1mL gives 10mg/mL, with 2mL gives 5mg/mL, and with 3mL gives 3.33mg/mL. The vial holds 10mg either way.
It depends on the concentration. A 100-unit syringe holds 1mL, so one unit is 0.01mL. At 5mg/mL (a 10mg vial in 2mL) 250mcg sits in 0.05mL, which is 5 units. At 10mg/mL the same 250mcg is 2.5 units.
It makes the solution less concentrated, not the peptide less potent. The same mass is spread through more liquid, so each draw is a larger volume for the same amount.
Water with 0.9% benzyl alcohol added. The benzyl alcohol inhibits bacterial growth, so a reconstituted vial keeps longer than it would with plain sterile water.
Divide the vial by the amount per draw. A 10mg vial is 10,000mcg, so at 250mcg it holds 40 draws, and at 500mcg it holds 20 — regardless of how much water was added.
You can, but treat the vial as single-use. Sterile water contains no preservative, so it offers nothing against contamination introduced after the vial is first entered.
Most peptide vials are 2mL or 3mL, and that capacity is the upper limit regardless of what concentration you would prefer.
A few milligrams of freeze-dried peptide occupies almost no space, and the cake is sometimes barely visible. Appearance tells you nothing about fill weight — the certificate does.
No. Swirl gently. Foaming is the visible sign of denatured peptide, and once it has foamed there is no way to tell how much was lost.
Freezing is not an improvement. Freeze-thaw cycles denature peptides, and the benzyl alcohol that protects a refrigerated vial does nothing for one that has been frozen.
For most peptides, weeks in the refrigerator away from light. Some compounds are shorter — NAD+ hydrolyses in water, glutathione oxidises on air exposure — and their guides say so.
Because the concentration is too high for that draw. At 10mg/mL, 250mcg is 0.025mL. Reconstituting in more water gives a larger, more measurable draw for the same amount.
No. It converts between vial strength, diluent volume, concentration and syringe units. These are laboratory research compounds and no dosing guidance is given.
No. Pre-mixed vials and pen cartridges arrive as a solution. This arithmetic applies to the plain lyophilised vial.