⚠️ Educational Disclaimer: For informational purposes only. Not medical advice. Full disclaimer

Table of Contents

  1. The Four Units
  2. Reading a Syringe
  3. What is Concentration?
  4. The Dosage Formula
  5. Worked Examples
  6. Quick Reference Chart

Understanding the Four Units

Milligrams (mg) — measures the total mass of lyophilized peptide in a vial (e.g., 5 mg vial).

Micrograms (mcg) — 1/1000 of a milligram. Doses are expressed in mcg. A 5 mg vial = 5,000 mcg.

Milliliters (ml) — the volume you draw into a syringe after reconstitution.

IU — the scale markings on a U-100 insulin syringe where 100 IU = 1 ml.

Unit Conversion
1 mg = 1,000 mcg | 100 IU = 1 ml | 1 IU = 0.01 ml

Reading an Insulin Syringe

A U-100 syringe has 100 major divisions each equal to 0.01 ml. Major tick marks appear every 10 IU (0.10 ml). Minor marks are typically every 2 IU (0.02 ml).

Syringe MarkVolume (ml)
10 IU0.10 ml
20 IU0.20 ml
25 IU0.25 ml
50 IU0.50 ml
100 IU1.00 ml

What is Concentration?

Concentration is the ratio of peptide mass to solution volume. It is set during reconstitution and determines how many ml or IU you draw per dose. Calculated as: (Vial mg × 1000) ÷ BAC Water (ml) = mcg/ml.

The Dosage Formula

Three steps convert a desired mcg dose to a syringe volume:

  1. Concentration (mcg/ml) = (vial mg × 1000) ÷ BAC water (ml)
  2. Volume (ml) = Desired dose (mcg) ÷ Concentration (mcg/ml)
  3. IU = Volume (ml) × 100

Use our peptide dosage calculator to do this instantly.

Worked Examples

Example 1 — 5 mg vial, 2 ml BAC water, 250 mcg dose

StepCalculationResult
Concentration(5 × 1000) ÷ 22,500 mcg/ml
Volume (ml)250 ÷ 2,5000.10 ml
Syringe (IU)0.10 × 10010 IU

Quick Reference Chart

Dose (mcg)@ 1,000 mcg/ml@ 2,500 mcg/ml@ 5,000 mcg/ml
100 mcg10 IU4 IU2 IU
250 mcg25 IU10 IU5 IU
500 mcg50 IU20 IU10 IU
1,000 mcg100 IU40 IU20 IU

Frequently Asked Questions

1 mg (milligram) = 1,000 mcg (micrograms). Vials are labeled in mg because that is the total powder mass. Doses are in mcg because the per-injection amount is a small fraction of a milligram.
If you add a different amount of BAC water than planned, your concentration changes. Recalculate your draw volume using the updated concentration with our dosage calculator.
Draw volumes vary because they depend on how much BAC water was used. Two researchers with the same vial and dose will draw different volumes if they used different water amounts. Always note your concentration alongside any dosage figure.