Tirzepatide Reconstitution Calculator

Mixing BPC-157: What to Know Before You Reconstitute

1. 01

   Bacteriostatic water vs. sterile water

   Bacteriostatic water is sterile water with 0.9% benzyl alcohol added, which inhibits bacterial growth in the vial after it has been punctured. That is the reason it is the standard choice for peptides used across multiple doses. The same vial gets drawn from repeatedly over days or weeks, and plain sterile water offers no protection once the seal is broken. Sterile water is generally treated as a single-use diluent. If a vial of BPC-157 will be used over more than one session, which is nearly always the case, bacteriostatic water is what people use.

2. 02

   How much water to add

   There is no single correct amount, and this trips people up more than anything else. The volume of water you add does not change how much BPC-157 is in the vial. A 5 mg vial contains 5 mg whether you add 1 mL or 3 mL. What the water volume changes is the concentration, and therefore how much liquid you draw for a given dose. Less water means a more concentrated solution and a smaller draw. More water means a more dilute solution and a larger, easier-to-measure draw.

   A common starting point for a 5 mg vial is 2 mL of bacteriostatic water, which produces a 2.5 mg/mL solution. At that concentration, each unit on a U-100 insulin syringe holds 25 mcg. But the right volume depends on your target dose and how many units you want to be counting on the syringe. That is precisely what the calculator above is for. Enter the vial size, the water volume, and your protocol's dose, and it shows the exact draw in units, with the syringe fill so you can sanity-check it visually.

3. 03

   Mixing technique

   The convention with peptides is to be gentle. Rather than injecting the water directly into the powder, people typically angle the needle so the stream runs down the inside wall of the vial, then let it sit or swirl it slowly until the powder fully dissolves. Shaking is generally avoided. It causes foaming and is widely considered bad practice with peptides. A fully dissolved vial of BPC-157 should be clear, with no visible particles. If it stays cloudy or has floating material after gentle swirling, something is off, and most people will not use it.

4. 04

   Storage before and after mixing

   Unopened lyophilized vials are typically stored somewhere cool and dark. Refrigeration in that state is common, though vendors vary in their guidance. After reconstitution the picture changes. The mixed vial goes in the refrigerator, and the widely followed convention is to discard it after about 28 days. That number comes from the bacteriostatic water itself, since 28 days is the standard window applied to punctured bacteriostatic vials, so the clock starts when you mix, not when you first draw. It is worth writing the mix date on the vial, because three weeks in, nobody remembers. Tracking vial age and expiration automatically is one of the things PepKit does, alongside logging each dose.

5. 05

   The syringe

   BPC-157 doses are small volumes, so the standard tool is a U-100 insulin syringe, usually the 1 mL 100-unit size, sometimes 0.5 mL or 0.3 mL. On a U-100 syringe, 100 units equal 1 mL, so each unit is 0.01 mL. Doses are usually communicated in mcg for BPC-157, which is why the math from mg in the vial to mcg per unit to units to draw is where people reach for a calculator instead of doing it at the counter.

6. 06

   Common mistakes worth avoiding

   The ones that come up constantly: shaking the vial instead of swirling, using single-use sterile water for a multi-week vial, forgetting to note the reconstitution date, redoing the dose math from memory each time instead of working it out once and saving it, and changing the water volume on a new vial without recalculating. The same vial size with different water is a different draw.