Peptide reconstitution calculator
Enter your vial size, how much bacteriostatic water you're adding, and your target dose. Get the exact draw on a U-100 insulin syringe — plus concentration and how many doses the vial holds.
on a U-100 insulin syringe
This is math, not medicine. The calculator converts numbers you provide; it does not suggest doses. Always confirm your protocol with a licensed clinician.
How the calculation works
Reconstitution math is three short steps:
- Concentration. Peptide in the vial, converted to mcg, divided by the water you added: 5 mg = 5000 mcg ÷ 2 mL = 2500 mcg/mL.
- Draw volume. Your dose divided by that concentration: 250 mcg ÷ 2500 mcg/mL = 0.1 mL.
- Syringe units. U-100 syringes mark 100 units per mL, so multiply the volume by 100: 0.1 mL = 10 units.
Two practical notes. First, adding more or less water never changes how much peptide is in the vial — only how concentrated each mL is. Second, if your draw lands on an awkward tick mark (say 7 units), you can reconstitute the next vial with a different water volume so the same dose lands on an easy round number.
Why we built an independent calculator
Most reconstitution calculators online are run by peptide vendors — useful, but built to sell you vials. This one is part of PepShot, a tracking app. No catalog, no checkout, nothing to upsell. The web tool is free forever; the app adds what a browser can't: it remembers every vial you've mixed, tracks what's left after each dose, and warns you before a vial runs dry or ages out.
This calculator, plus the whole protocol
PepShot for iPhone runs this math automatically for every dose — and tracks vials, cycles, sites, and reminders. Your protocol data stays on your device.
Download PepShotRelated guides: how to reconstitute peptides step by step · how long reconstituted peptides last · injection site rotation