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Peptide reconstitution calculator
Enter your vial, your water, and your dose — get the exact units to draw on an insulin syringe, the concentration, and how many doses your vial holds. You enter the numbers; this page does the arithmetic.
Draw to this mark
— units
Fill in your numbers above.
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Download on the App StoreReconstitution math, explained
How does the reconstitution calculation work?
Three steps of arithmetic. Concentration = peptide in the vial ÷ water added (e.g. 5 mg ÷ 2 mL = 2.5 mg/mL, or 2,500 mcg/mL). Draw volume = your dose ÷ concentration (250 mcg ÷ 2,500 mcg/mL = 0.1 mL). Syringe units = draw volume × 100 on a U-100 syringe (0.1 mL = 10 units).
How many units is my dose on an insulin syringe?
It depends on your concentration — which depends on how much water you added. The same 250 mcg dose can be 5, 10, or 20 units in different vials. That's exactly what this calculator computes: dose ÷ concentration × syringe factor.
What's the difference between U-100 and U-40 syringes?
The markings. A U-100 syringe has 100 units per mL; a U-40 has 40 units per mL. The same liquid volume reads as a different number of units, so always match the calculator's syringe setting to the syringe in your hand.
How many doses are in my vial?
Total peptide in the vial ÷ your dose, rounded down. A 5 mg (5,000 mcg) vial at 250 mcg per dose holds 20 full doses. The calculator shows this automatically in powder mode.
Is this medical advice?
No. This is a math utility: it converts numbers you enter and does not recommend, adjust, or validate any dose or compound. Many peptides are research chemicals not approved for human use. Consult a licensed clinician before starting, stopping, or changing anything health-related.
Educational reference and a math utility. Not medical advice. PeptideBro does not recommend doses — it converts numbers you enter. Nothing you type here is sent or stored anywhere; the math runs entirely in your browser. Consult a licensed clinician before starting, stopping, or modifying any protocol.