How I Solved the Math Problem Behind Peptide Dosing

When working with peptides or HGH, the most confusing part isn’t opening the vial; it’s the math. People often ask questions like:

• How much bacteriostatic water should I add?

• How do I know what mark on a U-100 syringe equals 250 mcg?

• How do I convert between mg, mcg, and IU without making mistakes?

While the math is not inherently difficult, repeating it for every vial, every dilution, and every dose becomes time-consuming and error-prone. This is what inspired me to build a simple dosing helper tool that automates the process.

Understanding the Problem

Peptides typically come as lyophilized (freeze-dried) powder. To use them, you must first reconstitute with bacteriostatic water (BAC water). Once dissolved, three main steps are required:

1. Calculate the concentration (mg/ml or mcg/ml).

2. Determine the volume needed for the desired dose.

3. Convert that volume into syringe units on a U-100 insulin syringe.

These steps are straightforward but easy to get wrong when done repeatedly.

The Formula Behind the Tool

The logic can be broken down into three simple equations:

Concentration (per ml) = Total Peptide (mg or IU) ÷ Diluent Volume (ml)

Injection Volume (ml) = Desired Dose (mg or mcg or IU) ÷ Concentration

Syringe Units = Injection Volume (ml) × 100

Because a U-100 syringe always has 100 units in 1 ml, this formula works universally.

Practical Example

Suppose you have a 5 mg vial of BPC-157 and you add 2 ml of BAC water. You want to measure a 250 mcg dose.

1. Convert vial content: 5 mg = 5,000 mcg.

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

3. Calculate injection volume: 250 ÷ 2,500 = 0.1 ml.

4. Convert to syringe units: 0.1 × 100 = 10 units.

In this case, the correct measurement would be drawing to the 10 mark on the syringe.

How the Helper Works

Instead of performing these steps manually every time, the dosing helper simplifies the process. The user only inputs three pieces of information:

• Vial size (mg or IU)

• Diluent volume (ml)

• Desired dose (mg/mcg/IU)

The tool then instantly calculates concentration, injection volume, and the exact syringe units to draw.

Why I Created It

In various forums and online discussions, I noticed the same dosing questions appear again and again. For example: What’s 200 mcg if I used 2 ml in a 5 mg vial? Or how many units do I pull for 1 IU after adding 1 ml to a 10 IU vial? These are repetitive math problems with the same underlying formula. By automating the calculation, users can save time and avoid dosing mistakes.

Future Improvements

There are many ways to expand this concept. A future version could include automatic unit conversion between mg, mcg, and IU, provide visual dosing charts for easy syringe reference, and offer a simple web interface for mobile use.

References

U.S. Food and Drug Administration. (2017). ANDA submissions for synthetic peptide drug products: Chemistry, manufacturing, and controls recommendations. FDA. https://www.fda.gov/media/107622/download

U.S. Food and Drug Administration. (2024). Clinical pharmacology considerations for peptide drug products. FDA. https://www.fda.gov/media/171901/download

U.S. Food and Drug Administration. (2020). The FDA alerts health care providers, compounders, and patients of dosing errors associated with compounded drugs. FDA. https://www.fda.gov/drugs/human-drug-compounding/fda-alerts-health-care-providers-compounders-and-patients-dosing-errors-associated-compounded

U.S. Food and Drug Administration. (2023). Immunogenicity assessment for peptide-related impurities in synthetic therapeutic peptide drug products. FDA.https://www.fda.gov/media/188008/download