Peptide Dosing Calculator: How to Calculate Your Dose from Vial Concentration

Written by Adam Maggio | Medically reviewed by Dr. Sarah Chen, PharmD, BCPS

To calculate peptide dose: divide the desired dose (mcg) by the vial concentration (mcg/mL) to get injection volume (mL). Example: 5 mg vial + 2 mL bacteriostatic water = 2,500 mcg/mL. For a 250 mcg dose: 250/2500 = 0.1 mL = 10 units on a 100-unit insulin syringe.

The Math Behind Peptide Dosing

One of the most common sources of confusion for people new to research peptides is calculating the correct injection volume to achieve a desired dose. The calculation is straightforward once you understand the relationship between vial content, reconstitution volume, and concentration.

Step 1: Calculate Vial Concentration

Concentration (mcg/mL) = Vial content (mcg) ÷ Reconstitution volume (mL). Example: A 5 mg (5,000 mcg) vial reconstituted with 2 mL of bacteriostatic water has a concentration of 5,000 ÷ 2 = 2,500 mcg/mL.

Step 2: Calculate Injection Volume

Injection volume (mL) = Desired dose (mcg) ÷ Concentration (mcg/mL). Example: For a 250 mcg dose from a 2,500 mcg/mL solution: 250 ÷ 2,500 = 0.1 mL.

Step 3: Convert mL to Insulin Syringe Units

Standard insulin syringes are marked in units, where 100 units = 1 mL. Therefore: 0.1 mL = 10 units, 0.2 mL = 20 units, 0.5 mL = 50 units, 1.0 mL = 100 units. For the example above: 0.1 mL = 10 units on a 100-unit insulin syringe.

Common Reconstitution Examples

BPC-157 (5 mg vial) + 2 mL BAC water = 2,500 mcg/mL. For 500 mcg: draw to 20 units. CJC-1295 (2 mg vial) + 2 mL BAC water = 1,000 mcg/mL. For 100 mcg: draw to 10 units. Ipamorelin (2 mg vial) + 2 mL BAC water = 1,000 mcg/mL. For 200 mcg: draw to 20 units. TB-500 (5 mg vial) + 2 mL BAC water = 2,500 mcg/mL. For 2,000 mcg (2 mg): draw to 80 units.

Tips for Accuracy

Use a fresh insulin syringe for each injection. Draw the solution slowly to avoid bubbles. If bubbles appear, gently tap the syringe and push them out before injecting. Double-check your calculation before injecting — errors in either direction (too much or too little) affect both safety and efficacy.