Peptide Dosage Calculator

Calculate the correct peptide dosage and syringe measurements for reconstituted peptides

About the Peptide Dosage Calculator

The Peptide Dosage Calculator is a precision tool designed for researchers and individuals needing to convert dry peptide weight into accurate liquid measurements for administration. When you receive a peptide, it typically arrives as a lyophilized (freeze-dried) powder in a vacuum-sealed vial. Before use, this powder must be reconstituted with a specific volume of bacteriostatic water or sterile water. Proper dosing requires understanding the relationship between the total milligrams in the vial, the volume of liquid added, and the markings on an insulin syringe.

This calculator eliminates the risk of manual calculation errors, which are common when converting between milligrams (mg) and micrograms (mcg). It provides clear instructions on where to pull the syringe plunger based on your specific reconstitution ratio. This tool is essential for ensuring protocol adherence, whether you are utilizing common research peptides like BPC-157, TB-500, or various growth hormone secretagogues. By entering your vial size, the amount of diluent used, and your target dose, you get a visual or numerical confirmation of the exact 'Units' required on a standard U-100 syringe.

Formula

Units on Syringe = (Desired Dose / Total Peptide Amount) * (Diluent Volume * 100)

The formula determines the number of units to draw on a U-100 insulin syringe based on your target dose. 'Desired Dose' is the amount you intend to inject (usually in mcg or mg), 'Total Peptide Amount' is the dry weight of the peptide in the vial (e.g., 5mg), and 'Diluent Volume' is the amount of bacteriostatic water added to the vial (in mL).

The constant '100' is used because a standard insulin syringe contains 100 units per 1mL. If you are using a U-40 syringe, you would replace 100 with 40. Ensure that the units for the Desired Dose and Total Peptide Amount are identical (convert mg to mcg by multiplying by 1,000) before performing the calculation.

Worked examples

Example 1: A researcher needs a 250mcg dose from a 5mg vial reconstituted with 2mL of water.

1. Convert 5mg vial to mcg: 5 * 1000 = 5000mcg.
2. Determine total units of water: 2mL * 100 = 200 units.
3. Calculate dose: (250 / 5000) * 200 = 10 units.

Result: 10 units on a U-100 syringe. The concentration is 250mcg per 10 units.

Example 2: An individual has a 2mg vial of GHRH and adds 1mL of bacteriostatic water, seeking a 300mcg dose.

1. Convert 2mg vial to mcg: 2 * 1000 = 2000mcg.
2. Determine total units of water: 1mL * 100 = 100 units.
3. Calculate dose: (300 / 2000) * 100 = 15 units.

Result: 15 units on a U-100 syringe. This provides exactly 300mcg of the peptide.

Example 3: A 10mg vial of Tirzepatide is reconstituted with 2mL of water, and the user needs a 1mg (1000mcg) dose.

1. Convert 10mg vial to mcg: 10 * 1000 = 10000mcg.
2. Determine total units of water: 2mL * 100 = 200 units.
3. Calculate dose: (1000 / 10000) * 200 = 20 units.

Result: 20 units on a U-100 syringe. Each 10 units contains 500mcg.

Common use cases

Calculating a 250mcg dose from a 5mg vial of BPC-157 reconstituted with 2mL of bacteriostatic water.
Determining how many units to draw for a 1mg dose of TB-500 when the vial contains 10mg of peptide.
Adjusting measurements when a researcher switches from 1mL of diluent to 3mL to make measurement easier for small doses.

Pitfalls and limitations

Mixing different units, such as entering the dose in mg but the vial size in mcg, will result in a 1,000-fold error.
Using a U-40 syringe with calculations meant for a U-100 syringe will result in an accidental overdose.
Failing to account for 'dead space' in some non-insulin syringes can lead to slight under-dosing of expensive peptides.
Assuming all insulin syringes are 1mL; always verify if your syringe is 0.3mL, 0.5mL, or 1.0mL before drawing.

Frequently asked questions

where to store reconstituted peptides after mixing

Most common peptides should be stored in the refrigerator at 36°F to 46°F (2°C to 8°C) after reconstitution. Excessive heat or light can degrade the chemical bonds, rendering the peptide ineffective. Always check the specific manufacturer guidelines for the peptide you are using.

do air bubbles change peptide dose accuracy

Bubbles in the syringe occupy volume that should be filled with your peptide solution, leading to under-dosing. To remove them, pull the plunger back to draw in a little air, then flick the side of the syringe until the bubbles rise to the top, and gently push the air out.

can i use sterile water instead of bacteriostatic water for peptides

Bacteriostatic water contains 0.9% benzyl alcohol, which acts as a preservative to prevent bacterial growth for up to 28 days. Sterile water lacks this preservative, meaning the solution must be used immediately or discarded after a single use to avoid infection risks.

how many units are in a 1ml syringe for peptides

Typical insulin syringes are 1mL (100 units), 0.5mL (50 units), or 0.3mL (30 units). On a standard U-100 syringe, each small tick mark usually represents 2 units of volume, though some smaller syringes have half-unit markings for precision.

how to calculate mcg per tick mark on syringe

To find the concentration, divide the total milligrams of the peptide by the milliliters of water added. For example, 5mg dissolved in 2mL of water results in a concentration of 2.5mg per mL, which is equivalent to 25mcg per unit on a U-100 syringe.