Peptide Dosage Calculator
Enter your vial amount, the bacteriostatic water you added, and your provider-directed dose. Get the exact insulin-syringe units to draw — live on the syringe below. It’s the same math built into the PeptideWiz app.
To draw a dose of 250 mcg, pull the plunger to 10.0 units.
Not medical advice. This calculator performs arithmetic on the numbers you enter. It does not recommend a dose, confirm that a peptide or protocol is safe or appropriate, or replace your provider. Always verify everything with a licensed medical professional.
How the calculation works
vial (mcg) ÷ water (mL)
How much peptide is in every millilitre after reconstitution.
dose (mcg) ÷ concentration
The millilitres that contain exactly your dose.
mL × 100
A U-100 insulin syringe holds 100 units per millilitre.
The unit conversion works because a standard U-100 insulin syringe holds 100 units per millilitre — so 0.25 mL is 25 units. A 0.3 mL (30-unit) or 0.5 mL (50-unit) syringe reads the same units; there’s just less total capacity, which the syringe above reflects.
Worked example
A 5 mg vial reconstituted with 2 mL of bacteriostatic water, drawing a 250 mcg dose:
| Vial amount | 5 mg = 5,000 mcg |
| Water added | 2 mL |
| Concentration | 5,000 ÷ 2 = 2,500 mcg/mL |
| Dose | 250 mcg |
| Volume to draw | 250 ÷ 2,500 = 0.10 mL |
| On the syringe | 0.10 × 100 = 10 units |
| Doses per vial | 5,000 ÷ 250 = 20 |
Reconstitution basics
Most research peptides arrive freeze-dried (lyophilized) and must be reconstituted before they can be measured. Adding more bacteriostatic water lowers the concentration, which means a larger, easier-to-read draw for the same dose; adding less does the opposite. The calculator lets you try different water volumes to find a draw that lands on clean marks on your syringe.
Frequently asked questions
Does more water change my dose?
No — the dose (amount of peptide) stays the same. More water only changes the volume you draw to reach that dose. It can make small doses easier to measure accurately.
What’s the difference between mcg and mg?
1 mg = 1,000 mcg. Vials are usually labelled in mg; doses are often expressed in mcg. The calculator handles the conversion for you — see units of measure.
Why insulin syringe units?
Insulin syringes have fine, closely spaced markings that make small reconstituted volumes easier to measure than a fractional-mL syringe. That’s why doses are commonly expressed in units.
Can I save these calculations?
Yes — the PeptideWiz app stores your vial, water, and dose per item, keeps a running inventory, and logs every administration so your history and reminders stay in one place.
Track it all in the PeptideWiz app →