Enter the milligrams in your BPC-157 vial, the bacteriostatic water you added and your dose in micrograms. You get the exact mark to draw to on an insulin syringe.
100 units per ml. Check the barrel — this is what almost every insulin syringe is.
U-100 insulin syringe · 50 unit barrel
Every BPC-157 unit question reduces to three numbers: the micrograms in the vial, the water you added, and the dose you want to draw. The calculator runs the same four steps you would do on paper. Here they are for the most common setup, a 5 mg vial with 2 ml of bacteriostatic water.
Step 1 — concentration. 5 mg ÷ 2 ml = 2.5 mg/ml. Every millilitre of solution now carries 2.5 mg, which is 2,500 mcg.
Step 2 — the dose in milligrams. BPC-157 doses are discussed in micrograms, so divide by 1,000. A 250 mcg dose is 0.25 mg.
Step 3 — the volume. 0.25 mg ÷ 2.5 mg/ml = 0.1 ml. That is the actual liquid you need to draw.
Step 4 — the syringe mark. On a U-100 insulin syringe, 1 ml is 100 units, so 0.1 ml is 10 units. That is the mark.
Run the same steps on a 10 mg vial with 2 ml of water and the answer halves: 10 ÷ 2 = 5 mg/ml, so 250 mcg is 0.05 ml, which is 5 units. Same vial label style, same dose, half the mark — because the concentration doubled. That is the whole reason this page exists.
All figures are units on a U-100 insulin syringe, where 100 units is 1 ml. The dose row is a spread of arbitrary values to show the arithmetic — it is a reference for reading the maths, not a suggestion of what to use.
| Vial + water | Conc. | 100 mcg | 200 mcg | 250 mcg | 300 mcg | 400 mcg | 500 mcg |
|---|---|---|---|---|---|---|---|
| 5 mg + 1 ml | 5 mg/ml | 2u | 4u | 5u | 6u | 8u | 10u |
| 5 mg + 2 ml | 2.5 mg/ml | 4u | 8u | 10u | 12u | 16u | 20u |
| 5 mg + 2.5 ml | 2 mg/ml | 5u | 10u | 12.5u | 15u | 20u | 25u |
| 10 mg + 2 ml | 5 mg/ml | 2u | 4u | 5u | 6u | 8u | 10u |
| 10 mg + 4 ml | 2.5 mg/ml | 4u | 8u | 10u | 12u | 16u | 20u |
Read the 5 mg + 1 ml row against the 10 mg + 2 ml row: they are identical. Both are 5 mg/ml, so every dose lands on the same mark. The vial size never decides the units — only the concentration does. What the bigger vial changes is how long it lasts: at 250 mcg per draw, a 5 mg vial holds 20 doses and a 10 mg vial holds 40.
The 2 mg/ml row is the easiest to read in one way and the worst in another. Its marks sit furthest apart, so a small hand wobble costs the least. But 250 mcg lands on 12.5 units — exactly between marks on most barrels. If 250 mcg is your usual draw, 2.5 mg/ml puts it on a clean 10 instead. Working backwards from the dose you draw most often is the whole skill of choosing a water volume.
One physical check before copying the 10 mg + 4 ml row: make sure the vial can actually hold 4 ml. Many peptide vials top out near 3 ml. If yours is small, get the same 2.5 mg/ml concentration from a 5 mg vial and 2 ml instead.
A unit on an insulin syringe measures volume, not mass. One unit on a U-100 syringe is one hundredth of a millilitre, always. How many micrograms ride in that volume depends entirely on how much water went into the vial — and that is a choice you made, not a property of BPC-157.
This is why a unit count copied from a forum post is useless. When someone writes that they draw to 10 units, that number carries no information without their vial size and water volume. Two people with identical 5 mg vials can draw to 5 units and 10 units for the same 250 mcg dose, and both are right. They reconstituted differently.
The water volume itself is never the dose. Adding more water does not weaken the vial — the same total micrograms are in there — it just spreads them across more liquid, so each dose needs a bigger draw. Dilute vials cost you barrel space; concentrated vials cost you reading precision. That trade is the only decision the water volume makes.
Almost every insulin syringe sold is U-100: 100 units per millilitre. The barrels come in three common sizes — 0.3 ml (30 units), 0.5 ml (50 units) and 1 ml (100 units). A smaller barrel is not weaker; it holds less but spaces its marks wider, which makes small BPC-157 draws like 5 or 10 units much easier to read accurately.
Check the scale printed on the barrel before trusting any number on this page. A U-40 syringe, mostly veterinary, has 40 units per millilitre — drawing to “10 units” on one of those pulls two and a half times the volume that the same mark means on a U-100. The calculator above has a U-40 switch if that is genuinely what you have.
If your answer keeps landing between marks, do not squint — change the water volume. The calculator suggests a volume that puts your dose on a round mark whenever the current answer is awkward to read.
Search for BPC-157 dosing and you will find confident numbers everywhere — figures like 200 to 500 mcg once or twice a day are commonly discussed on forums and repeated by the sites that sell it. It matters where those numbers did not come from: there are no established human dosing guidelines for BPC-157, because the human trials that would produce them have not been done.
The reported figures are community habit, not evidence. They describe what people say they use, scaled loosely from animal work. This page does not repeat them as a recommendation, and the dose column in the table above is a maths illustration, not a protocol.
What the calculator does is narrower and more honest: if you have already settled on a figure with someone qualified to advise you, it tells you which mark on the syringe corresponds to it — and it does that part exactly.
BPC-157 is a synthetic chain of 15 amino acids, based on a fragment of a protective protein found in human gastric juice. Nearly all published research on it is in animals, mostly rodents. Human data is close to nonexistent, which is why every claim you read about what it does should be read as a claim about rats.
Its regulatory position is unambiguous. It is not an approved medicine anywhere. The FDA has flagged it as a substance with safety concerns for use in compounded drugs, and WADA bans it in sport as an unapproved compound. Vials sold online are labelled for laboratory research, and that label is doing legal work — it means no regulator has reviewed what is inside.
That last point has a practical consequence for the arithmetic on this page. The calculation trusts the label: a “5 mg” vial is treated as containing 5 mg. With grey-market research compounds, actual content and purity vary by supplier, and independent testing of such products has repeatedly found vials that are underfilled, overfilled or degraded. The maths here is exact; the label it starts from may not be. That uncertainty cannot be calculated away, and no vendor is endorsed here.
Once water goes in, the clock starts. Reconstituted peptide is less stable than the dry powder, so the standard practice is to keep the mixed vial refrigerated and out of light, and to use bacteriostatic water rather than plain sterile water — the benzyl alcohol in it suppresses bacterial growth across the weeks a multi-dose vial stays in use. The water itself keeps to its own schedule, which is covered separately in how long bacteriostatic water lasts.
Write the concentration and the date on the vial the moment you mix it. A 5 mg vial at 2 ml and one at 1 ml look identical on the shelf, and an unlabelled vial three weeks later tells you nothing about what a unit is worth. This one habit prevents the largest category of dosing error in practice. If you would rather not recalculate each time, the printable cheat sheet carries the concentration and units tables in one place.
Mixing up mg and mcg. This is the big one. BPC-157 doses are discussed in micrograms, vial sizes in milligrams — a factor of 1,000 apart. Typing 250 into a milligram field when you meant micrograms produces an answer a thousand times too large. The calculator flags a dose bigger than the vial, which is how that slip usually shows itself.
Copying someone else’s units. A unit count without a vial size and water volume attached is noise. Always recalculate from your own vial.
Forgetting the water volume you used. A vial mixed at 1 ml and one mixed at 2 ml need different marks for the same dose. Label the vial when you mix it.
Assuming every syringe is U-100. Nearly all are, but U-40 syringes exist, and the same mark means a very different volume on one. Check the barrel.
Overfilling the vial. Water volumes that produce nice round numbers are only usable if the vial physically holds them. Check capacity before planning around 4 or 5 ml.
Working with a different compound, or in milligrams? Use the general peptide reconstitution calculator, or the tirzepatide calculator for milligram-dosed vials.