Peptide Units Explained: mg, mcg, IU & Conversions

Quick Reference

Common Conversions

Mass Conversions

1 g = 1,000 mg
1 mg = 1,000 mcg
1 g = 1,000,000 mcg

Examples:

• 5 mg = 5,000 mcg
• 250 mcg = 0.25 mg
• 0.5 mg = 500 mcg

Volume Conversions (for insulin syringes)

With U-100 insulin syringes:

1 ml = 100 units (marks on syringe)
0.5 ml = 50 units
0.1 ml = 10 units
0.01 ml = 1 unit

The Tricky Part: Converting Volume to Mass

Important: ml (volume) and mcg (mass) are different things. You can only convert between them if you know the concentration of your solution.

The Formula

mcg per ml = (total peptide mg × 1000) ÷ total ml of liquid

Example Calculation

Scenario: 5mg peptide reconstituted with 2ml bacteriostatic water

Step 1: Convert mg to mcg
5 mg × 1,000 = 5,000 mcg total

Step 2: Calculate concentration
5,000 mcg ÷ 2 ml = 2,500 mcg/ml

Step 3: Now you can convert
0.1 ml = 250 mcg
0.2 ml = 500 mcg
0.5 ml = 1,250 mcg

Common Reconstitution Scenarios

Understanding IU (International Units)

IU is a standardized measure of biological activity, not mass. The conversion factor varies by substance.

HGH (Human Growth Hormone)

1 IU HGH ≈ 0.33 mg (or 333 mcg)
3 IU HGH ≈ 1 mg

Note: This ratio can vary slightly between manufacturers.

Insulin

U-100 insulin: 100 units per ml
U-40 insulin: 40 units per ml (less common)

Why IU Exists

IU measures biological effect, not just mass. Two preparations might have the same weight but different potencies. IU standardizes based on actual biological activity.

Common Questions Answered

"How many mcg is 0.1ml?"

It depends on concentration. See the table above or use this formula:

mcg = concentration (mcg/ml) × volume (ml)

If your 5mg peptide is in 2ml water:

• Concentration = 2,500 mcg/ml
• 0.1ml = 2,500 × 0.1 = 250 mcg

"How do I measure 250 mcg?"

1. Know your concentration (mcg/ml)
2. Calculate volume needed: 250 ÷ concentration = ml
3. Use appropriate syringe

Example: At 2,500 mcg/ml concentration:

• 250 mcg ÷ 2,500 mcg/ml = 0.1 ml = 10 units on insulin syringe

"What's the difference between mcg and μg?"

They're the same thing:

• mcg = microgram (common in US)
• μg = microgram (scientific notation)

Both equal 1/1,000,000 of a gram or 1/1,000 of a milligram.

"How do I convert IU to mg for HGH?"

HGH: IU × 0.33 = mg
HGH: mg × 3 = IU

Examples:
2 IU = 0.66 mg = 660 mcg
5 IU = 1.65 mg = 1,650 mcg
10 IU = 3.3 mg = 3,300 mcg

Insulin Syringe Basics

U-100 Syringes (Most Common)

Reading the Syringe

U-100 syringe markings:

100 ─┐
 90  │
 80  │
 70  │
 60  │  ← Each line = 1 or 2 units
 50  │     depending on syringe
 40  │
 30  │
 20  │
 10  │
  0 ─┘

Volume Conversion

10 units = 0.1 ml
25 units = 0.25 ml
50 units = 0.5 ml
100 units = 1 ml

Quick Conversion Chart

mg to mcg

HGH: IU to mg

Syringe Units to ml

Practical Examples

Example 1: BPC-157

Setup: 5mg vial, reconstituted with 2ml BAC water

Concentration: 5,000 mcg ÷ 2 ml = 2,500 mcg/ml

To get 250 mcg:
250 ÷ 2,500 = 0.1 ml = 10 units

To get 500 mcg:
500 ÷ 2,500 = 0.2 ml = 20 units

Example 2: HGH

Setup: 10 IU vial, reconstituted with 1ml BAC water

10 IU = 3.3 mg = 3,300 mcg total
Concentration: 10 IU/ml or 3,300 mcg/ml

To get 2 IU:
2 ÷ 10 = 0.2 ml = 20 units

To get 4 IU:
4 ÷ 10 = 0.4 ml = 40 units

Example 3: Semaglutide

Setup: 3mg vial, reconstituted with 3ml BAC water

Concentration: 3,000 mcg ÷ 3 ml = 1,000 mcg/ml = 1 mg/ml

To get 0.25 mg (250 mcg):
250 ÷ 1,000 = 0.25 ml = 25 units

To get 0.5 mg (500 mcg):
500 ÷ 1,000 = 0.5 ml = 50 units

Use Our Calculator

For quick conversions, use our Peptide Unit Converter which handles:

• mg to mcg
• IU to mg (HGH)
• ml to units
• Body weight (kg to lbs)

Summary

The key is always knowing your concentration after reconstitution. Once you have that, all other calculations become simple multiplication and division.