Peptide Reconstitution Calculator

The reverse mode answers the question 'how much bacteriostatic water should I add so each dose lands on a clean tick mark?' You enter the vial size, the dose you want, and the units you'd like to draw — it tells you the exact mL of BAC water to mix in.

Concentration (mg/mL) = vial mg ÷ BAC water mL. Volume (mL) = dose (mg) ÷ concentration. Units on a U-100 syringe = volume × 100. Our calculator handles all of this and lets you pick U-100, U-50, U-40, or a 1 mL tuberculin syringe.

U-100 insulin syringes are by far the most common for subcutaneous peptide use because they read in 100 units per mL with very fine markings. U-40 and U-50 syringes are used in some veterinary or specialty contexts. Always match the syringe markings to what your calculator outputs.

Yes — for compounded vial product. Brand pen products (Ozempic, Wegovy, Mounjaro, Zepbound) use a fixed concentration; for those see our GLP-1 dose escalator. For a compounded multi-dose vial of semaglutide or tirzepatide, this calculator gives you the units per dose.

The math is exact for the inputs you provide. Real-world variability comes from vial overfill (most vials contain 5–15% extra solvent), syringe dead-space, and operator technique. Always verify the math yourself and consult a licensed physician.