Peptide Reconstitution / Dosage Calculator

Work out the concentration after reconstitution and how many units to draw on a U-100 insulin syringe for a prescribed dose.

LiveHealthExpert review pendingURL: /peptide-calculator

Enter your values

mg
mL
Enter the dose your prescriber gave you. This tool does not suggest doses.
Report error

Did we solve your problem today?

How to use this calculator

Enter your values. The result updates as you type; press Calculate to confirm and jump to the result on mobile. Use Share to send the calculator with your result.

Reconstitution math

concentration (mcg/mL) = vial mg × 1,000 ÷ mL of diluent volume (mL) = dose (mcg) ÷ concentration U-100 units = volume (mL) × 100

Example: a 5 mg vial mixed with 2 mL gives 2,500 mcg/mL. A prescribed 250 mcg dose is 250 ÷ 2,500 = 0.1 mL, which is 10 units on a U-100 insulin syringe.

Reading a U-100 syringe

U-100 insulin syringes are marked in units where 100 units = 1 mL, so each unit is 0.01 mL. A 0.3 mL syringe holds 30 units (often with half-unit marks), a 0.5 mL syringe 50 units and a 1 mL syringe 100 units. Pick a syringe where your dose fills a good part of the barrel for easier reading.

Safety

  • Only use medicines prescribed for you, from a licensed pharmacy.
  • Follow your pharmacist’s instructions on diluent type, storage and how long the mixed vial stays usable.
  • Don’t change the diluent volume without recalculating: more water means more units for the same dose.
  • The FDA has warned that some peptide substances used in compounding may present significant safety risks.

Frequently asked questions

How many units is 250 mcg from a 5 mg vial with 2 mL water?

10 units (0.1 mL) on a U-100 syringe.

How much bacteriostatic water should I add?

Use the volume on your prescription or pharmacy label. The tool shows how the volume changes the units you draw.

About this tool

Written by
[Author: to be assigned]
Reviewed by
Expert review pending
Last updated
31 Oct 2026

See our methodology and editorial policy. Think something’s off? Report an error with this tool.

Related tools

All Health & Fitness
Live

A1C Calculator

Convert hemoglobin A1C to estimated average glucose (eAG) in mg/dL or mmol/L, or back again, with ADA ranges.

Health
Live

IQ Percentile Calculator

Convert an IQ score to a percentile and classification, or find the IQ for a given percentile.

Health
Live

Pack-Year Calculator

Calculate smoking pack-years from cigarettes per day and years smoked, and check the USPSTF lung cancer screening criteria.

Health