Instrument · free · no signup
Peptide reconstitution calculator
Enter what's on your vial, how much bacteriostatic water you add, and the dose your provider gave you. The instrument returns the exact draw in insulin-syringe units - and warns you when the result is too small or too large to measure reliably.
Enter vial size, water volume, and the dose your provider gave you.
This tool converts the numbers you enter (dose ÷ concentration = volume). It never suggests a dose. The FDA has documented hospitalizations caused by mg / ml / unit conversion errors with vial-and-syringe products - if the readout surprises you, stop and verify with your prescriber or pharmacist.
Per-peptide calculators
The three formulas this instrument runs
Nothing here is proprietary - write these on the vial box if you prefer paper:
- Concentration = peptide in vial (mg) ÷ bacteriostatic water added (ml)
- Volume to draw = dose (mg) ÷ concentration (mg/ml)
- Insulin units = volume (ml) × 100 (on the U-100 scale, every syringe size)
Worked example: a 10 mg vial with 2 ml of water is 5 mg/ml. A 2.5 mg dose is 2.5 ÷ 5 = 0.5 ml = 50 units. Add 4 ml of water instead and the same 2.5 mg dose becomes 1 ml = 100 units - same dose, different number on the barrel. That's why unit counts are never portable between vials.
Frequently asked questions
How does a peptide calculator work?
Three numbers define everything. Vial content ÷ water volume = concentration (mg/ml). Your dose ÷ concentration = the volume to draw (ml). On a U-100 insulin syringe, each unit is 0.01 ml, so volume × 100 = units. The calculator runs that arithmetic and flags results that are hard to measure accurately.
How much bacteriostatic water should I add?
Water volume never changes the dose - only the concentration. More water means each dose is a larger, easier-to-read draw; less water means smaller draws. A practical rule from compounding practice: choose a volume that puts your typical draw between 10 and 50 units on the syringe.
What is the difference between mg, mcg, and units?
Milligrams and micrograms measure the amount of peptide (1 mg = 1,000 mcg). Units measure volume on an insulin syringe (1 U-100 unit = 0.01 ml). A unit contains more or less peptide depending on how the vial was reconstituted - which is why copying someone else's unit count is the classic dosing error.
Why doesn't this calculator suggest a dose?
Because dose selection is a medical decision, and most compounds people calculate for are not FDA-approved. This tool exists to prevent conversion errors in math you and your clinician have already decided on - the FDA has documented hospitalizations from patients drawing 5-20× the intended dose from vials.