Free web tool
Peptide reconstitution calculator
Vial, water, dose. Get the units to draw on a U-100 insulin syringe, the concentration and how many doses the vial holds. Pick a compound to prefill common vial sizes.
Reconstitution calculator
Free in the appHow the math works
Reconstitution is three divisions. First, concentration: the milligrams of peptide in the vial divided by the millilitres of bacteriostatic water you added. A 5 mg vial with 2 mL of water is 2.5 mg/mL, or 2,500 mcg/mL. Second, volume: your dose divided by that concentration. A 250 mcg dose is 250 ÷ 2,500 = 0.1 mL. Third, units: a U-100 insulin syringe has 100 units per mL, so 0.1 mL is 10 units.
The only number you control after the vial is mixed is the dose. The only number you control before is the water. More water means more units per dose, which is easier to measure for small doses; less water means fewer units, which matters when a dose would not fit in one syringe.
Common mistakes the calculator catches
- Mixing mg and mcg. 1 mg is 1,000 mcg. The unit selector keeps the dose and the vial in the same currency.
- Over 100 units. A 1 mL syringe cannot hold it in one draw. Peppy warns you in the editor before shot day.
- Under 2 units. Too small to measure well. Add more water next time so the same dose spreads across more units.
- Half-unit draws. Syringe marks are the practical limit; the calculator tells you when a dose lands between them.
Calculators by compound
Every vial compound in Peppy has its own page with the calculator prefilled for common vial sizes, its typical frequency and, where the catalog lists one, a half-life chart.
Save it in Peppy
In the app the calculator lives inside the protocol editor. Enter the vial and the water once and the units to draw show on the Today tab, in the Log shot sheet and on the Home Screen widget (Pro) every time. Peppy also counts doses left in the vial and tells you the day you run out (Pro). Read the full reconstitution guide.
The calculator, inside your tracker
Units to draw on every shot, plus the countdown, the body map and the log. Free on iPhone.
Free · iPhone · no accountFrequently asked
How do you calculate peptide reconstitution?
Concentration = peptide in the vial (mg) ÷ water added (mL). Volume to draw = dose (mg) ÷ concentration. Units on a U-100 insulin syringe = volume in mL × 100. Example: 5 mg in 2 mL is 2.5 mg/mL; a 250 mcg dose is 0.1 mL, which is 10 units.
How many units are in 1 mL?
A U-100 insulin syringe has 100 units per mL, so 1 unit is 0.01 mL. A 0.5 mL syringe holds 50 units, a 0.3 mL syringe holds 30.
What if the dose is more than 100 units?
It will not fit a 1 mL syringe in one draw. Reconstitute with less water so the same dose takes fewer units, or ask your prescriber. The calculator warns you when this happens.
Is this the same as the calculator in the Peppy app?
Same math. In Peppy it lives inside the protocol editor, so the units to draw show on the Today tab and in the Log shot sheet every time, and it also runs standalone from Settings.
Does the calculator tell me what dose to take?
No. It converts a dose your prescriber set into units on a syringe. It is a mathematical conversion only. Always verify each draw-up yourself.
Not medical advice. Peppy is a tracking tool, not medical advice. Dose calculations are mathematical conversions only. Always follow your prescriber's instructions and verify every draw-up yourself.