Peptide Dosage Calculation Methods

Understanding Peptide Concentration Math

Calculating peptide dosages requires understanding the relationship between three key variables: the total amount of peptide (in milligrams), the volume of solvent used for reconstitution (in milliliters), and the final concentration (typically expressed as mg/mL or mcg/mL).

The fundamental formula is: Concentration = Mass ÷ Volume

For example, if you dissolve 10mg of peptide in 2mL of bacteriostatic water, your concentration is 10mg ÷ 2mL = 5mg/mL (or 5,000mcg/mL).

Converting Units

Peptide dosages are often discussed in micrograms (mcg) rather than milligrams (mg). The conversion is straightforward:

• 1 mg = 1,000 mcg (micrograms)
• 1 mL = 1,000 µL (microliters)
• 1 mL = 100 IU on a standard insulin syringe (U-100)

So if you have a solution at 5mg/mL concentration, that's equivalent to 5,000mcg/mL. Each 0.1mL (or 10 IU on an insulin syringe) contains 500mcg.

Step-by-Step Calculation Example

Given Information

• Peptide vial: 10mg
• Desired dose: 250mcg
• Reconstitution volume: 2mL bacteriostatic water

Step 1: Calculate Concentration

Concentration = 10mg ÷ 2mL = 5mg/mL (5,000mcg/mL)

Step 2: Calculate Volume per Dose

Volume needed = Desired dose ÷ Concentration
Volume needed = 250mcg ÷ 5,000mcg/mL = 0.05mL (or 5 IU)

Step 3: Verify Using Insulin Syringe

On a U-100 insulin syringe, 5 IU = 0.05mL.
0.05mL × 5,000mcg/mL = 250mcg ✓

Choosing Your Reconstitution Volume

The volume of water you add affects dosing convenience and accuracy:

• More water = lower concentration = larger injection volumes (easier to measure precisely)
• Less water = higher concentration = smaller injection volumes (more convenient but harder to measure)

Quick Reference Table

Common reconstitution scenarios for a 10mg peptide vial:

• + 1mL water = 10mg/mL → 100mcg per 0.01mL (1 IU)
• + 2mL water = 5mg/mL → 100mcg per 0.02mL (2 IU)
• + 2.5mL water = 4mg/mL → 100mcg per 0.025mL (2.5 IU)
• + 5mL water = 2mg/mL → 100mcg per 0.05mL (5 IU)