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How to reconstitute BPC-157
BPC-157 is the compound where the arithmetic bites hardest, for one reason: it is dosed in micrograms while the vial is labelled in milligrams. A typical dose is 250 mcg, which is 0.25 mg, which is one fortieth of a 10 mg vial. Every decimal place matters and the error mode is a factor of ten. This page has the mcg-to-units chart, and explains why BPC-157 wants more water than a GLP-1, not less.
First, the conversion that causes the errors: 1 mg = 1,000 mcg, so 250 mcg = 0.25 mg. Then units = (dose mg ÷ concentration) × 100. Write your dose in mg before you touch the syringe and the tenfold mistakes stop happening. Or skip the arithmetic with the reconstitution calculator.
What you need
- • A lyophilized BPC-157 vial, typically 5 mg or 10 mg
- • Bacteriostatic water. BPC-157 is usually dosed daily for weeks, so the preservative matters more here than for a weekly compound
- • A U-100 insulin syringe. The doses are small, so syringe resolution is the binding constraint
- • Alcohol swabs, clean hands, a clean surface
The steps
Prep. Wash your hands. Swab the rubber stopper of both the compound vial and the bacteriostatic water with alcohol and let them air dry.
Draw your water. Pull the volume you decided on above into a syringe. This number is the single decision that sets everything downstream.
Add it slowly. Insert the needle and let the water run down the inside glass wall, not jetting straight onto the powder. Foam means sheared peptide.
Dissolve gently. Swirl the vial or roll it between your palms. Never shake. Wait until it is completely clear. Cloudiness or floating particles means do not use it.
Draw the dose. Work out your units from the chart above, swab the stopper again, and draw on a U-100 syringe, tapping air bubbles back out.
Label and refrigerate. Write the concentration and the date on the vial. In four weeks you will not remember either.
Dose-to-units chart
Common BPC-157 dosing runs 100 to 500 mcg, once or twice daily. Here is what that costs in units across the sensible reconstitutions:
| Vial + water | Concentration | 100 mcg | 250 mcg | 500 mcg |
|---|---|---|---|---|
| 5 mg + 1 mL | 5 mg/mL | 2 u | 5 u | 10 u |
| 5 mg + 2 mL | 2.5 mg/mL | 4 u | 10 u | 20 u |
| 5 mg + 3 mL | ~1.67 mg/mL | 6 u | 15 u | 30 u |
| 10 mg + 2 mL | 5 mg/mL | 2 u | 5 u | 10 u |
| 10 mg + 3 mL | ~3.3 mg/mL | 3 u | 7.5 u | 15 u |
| 10 mg + 5 mL | 2 mg/mL | 5 u | 12.5 u | 25 u |
Red = too few units to draw reliably. Below roughly 5 units, a one-unit error is a 20% or worse dose error.
Why BPC-157 wants more water, not less
Everything you may have read about reconstituting GLP-1s points the wrong direction here. With tirzepatide the problem is doses too large for the syringe, so you concentrate. With BPC-157 the doses are two orders of magnitude smaller and the problem is the opposite: draws so tiny that the syringe cannot resolve them.
The target to aim for is a dose that lands somewhere in the 10 to 30 unit range. That is far enough up the barrel that a one-unit misread is a small percentage error, and it is still comfortably within a single syringe. For a 5 mg vial and a 250 mcg dose, 3 mL of bacteriostatic water puts you at 15 units, which is close to ideal. Using 1 mL instead would give you a 5-unit draw, where being one unit off is a 20% dose error.
There is a real limit on how far you can take this. More water means a larger injection volume and a shorter practical vial life once you account for the beyond-use date, and most bacteriostatic water comes in 30 mL bottles that you do not want to burn through. Three to five millilitres is the sensible band.
Vial longevity, which actually binds here
BPC-157 is unusual on this site in being a genuinely daily compound, often twice daily, typically run in blocks of four to eight weeks. That changes the maths of which vial to buy. A 5 mg vial at 250 mcg twice daily is 500 mcg a day, so ten days of use. A 10 mg vial at the same dose is twenty days. Both sit inside a 28-day beyond-use window, which is the rare case where the larger vial is the sensible purchase rather than the wasteful one.
It also means you will be puncturing the stopper forty times or more over the vial's life, which is exactly the scenario bacteriostatic water's preservative exists for. Plain sterile water is not an acceptable substitute here. The vial longevity calculator will do the days-remaining arithmetic against your actual schedule.
Storage & beyond-use dating
Reconstituted BPC-157 keeps for roughly 28 days refrigerated at 2-8 °C, which for most protocols is about the length of a cycle. Keep it cold, keep it dark, do not freeze and thaw it repeatedly, and label the vial with both the concentration and the mix date. Because you are opening this vial daily rather than weekly, minimise the time it spends out of the fridge: get in, draw, and get it back. Fuller detail in the peptide storage guide.
Common mistakes
- • Confusing mcg with mg. A 250 mcg dose is 0.25 mg. Entering 250 mg into a calculator returns a nonsense answer a thousandfold out.
- • Over-concentrating out of habit from GLP-1 charts. A 2-unit draw cannot be measured accurately.
- • Using plain sterile water in a vial you will puncture forty times over a month.
- • Reading a 5 mg chart while holding a 10 mg vial. Same water volume, double the concentration, half the units.
- • Shaking rather than swirling. Same rule as every other peptide: foam is damage.
BPC-157 is not an FDA-approved drug. It is sold for research use only, is not available as a compounded prescription product in the United States following FDA action on certain peptide categories, and its human safety and efficacy data are limited to small studies and animal work. This page explains reconstitution mechanics; it is not medical advice or an endorsement. Research-use vials carry no guarantee of stated strength, purity or sterility. See the US peptide and compounding status, and take any decision with a licensed clinician.
Skip the arithmetic
OptiPin's free reconstitution calculator takes your vial size, water volume and target dose and returns the exact units, flagging the draws that will not fit a syringe. The app then logs every injection, tracks what is left in the vial and warns you before it runs out or expires. iOS, on-device, no account.
Open the calculatorFrequently asked questions
How much bacteriostatic water for a 5 mg BPC-157 vial?
Three millilitres is a good default. It gives roughly 1.67 mg/mL, which puts a 250 mcg dose at 15 units on a U-100 syringe: high enough up the barrel to read accurately and low enough to leave room. Two millilitres also works, giving 10 units for the same dose. One millilitre concentrates it too far for comfortable measurement of small doses.
How many units is 250 mcg of BPC-157?
With a 5 mg vial in 2 mL it is 10 units, and in 3 mL it is 15 units. With a 10 mg vial in 2 mL it is 5 units. The dose in micrograms is fixed by your protocol; the units follow entirely from how much water you added, so always compute from your own vial.
How do I reconstitute a 10 mg BPC-157 vial?
Use 3 to 5 mL of bacteriostatic water. Five millilitres gives 2 mg/mL, putting a 250 mcg dose at 12.5 units and a 500 mcg dose at 25 units, both comfortable to draw. Two millilitres gives 5 mg/mL, where a 100 mcg dose becomes an unmeasurable 2 units.
Is 250 mcg the same as 0.25 mg?
Yes. One milligram is a thousand micrograms, so 250 mcg is 0.25 mg and 500 mcg is 0.5 mg. This conversion is the single most common source of serious BPC-157 dosing errors, because getting it wrong moves the dose by a factor of a thousand. Convert to mg on paper before you calculate units.
How long does reconstituted BPC-157 last?
Around 28 days refrigerated is the usual working figure. Because BPC-157 is dosed daily, a vial is typically finished well inside that window, but label the mix date anyway and discard on it rather than trusting memory.
Sources & further reading
- Bacteriostatic Water for Injection, USP - DailyMed label (why the preservative matters for a daily-use vial).
- USP General Chapter <797> - Sterile Compounding (aseptic technique, beyond-use dating).
- US peptide & compounding regulatory status (where BPC-157 currently sits).
U-100 syringe: 100 units = 1 mL. Vial strengths and fill volumes vary between suppliers, so always verify the stated strength on your own vial before calculating. This page is educational and is not medical advice.
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