Introduction
Understanding how to calculate peptide dosage is essential for anyone working with research peptides. Whether you're a researcher or simply curious about how peptides work, accurate dosage calculation ensures consistency and reliability in your work. This guide walks you through everything you need to know.
Key Terms You Need to Know
Before diving into calculations, it's important to understand a few fundamental terms:
- Lyophilised peptide: The dry powder form of a peptide, measured in milligrams (mg).
- Bacteriostatic water (BAC water): The sterile water used to reconstitute (dissolve) the peptide powder.
- Concentration: The amount of peptide per unit of liquid, typically expressed as mcg/mL or mg/mL.
- Dose: The amount of peptide administered in a single use, typically measured in micrograms (mcg) or milligrams (mg).
The Basic Peptide Dosage Formula
Once you know how much BAC water you've added to your peptide vial, you can calculate the concentration using this formula:
Concentration (mcg/mL) = Total peptide (mcg) ÷ Volume of BAC water added (mL)
For example, if you have a 5mg (5,000 mcg) vial and add 2mL of BAC water:
5,000 mcg ÷ 2 mL = 2,500 mcg/mL
How to Calculate Your Injection Volume
Once you know the concentration, you can work out how many units to draw in an insulin syringe:
Volume (mL) = Desired dose (mcg) ÷ Concentration (mcg/mL)
Using the example above, if your desired dose is 250 mcg:
250 ÷ 2,500 = 0.1 mL (10 units on a 100-unit insulin syringe)
Using an Insulin Syringe
Most researchers use a standard U-100 insulin syringe (100 units = 1 mL). Here's how the units translate:
- 10 units = 0.1 mL
- 20 units = 0.2 mL
- 50 units = 0.5 mL
- 100 units = 1.0 mL
So if your calculation gives you 0.1 mL, you draw to the 10-unit mark on your syringe.
Quick Reference Example Table
Here's a quick reference for a 5mg vial reconstituted with different volumes of BAC water:
| BAC Water Added | Concentration | 250 mcg dose = | 500 mcg dose = |
|---|---|---|---|
| 1 mL | 5,000 mcg/mL | 5 units | 10 units |
| 2 mL | 2,500 mcg/mL | 10 units | 20 units |
| 5 mL | 1,000 mcg/mL | 25 units | 50 units |
Use Our Peptide Calculator
Not a fan of manual maths? We've built a free Peptide Dosage Calculator that does all the work for you. Simply enter your vial size, BAC water volume, and desired dose — and it instantly tells you how many units to draw.
Tips for Accurate Dosing
- Always use a fresh, sterile insulin syringe for each use.
- Record the volume of BAC water you add to each vial so you can always calculate your concentration.
- Store reconstituted peptides in the refrigerator and use within the recommended timeframe.
- Label your vials with the date of reconstitution and concentration.
Summary
Calculating peptide dosage comes down to two simple steps: work out your concentration (peptide ÷ BAC water), then divide your desired dose by that concentration to get your injection volume. With a little practice, this becomes second nature — and our Peptide Calculator is always here to help.