Peptide Reconstitution & Dosing Calculator

How Reconstitution Works

Most research peptides arrive as a lyophilized (freeze-dried) powder in a sealed vial. Before use, the peptide must be reconstituted by adding a diluent, typically bacteriostatic water (BAC water), to dissolve the powder back into a liquid solution.

The concentration of the resulting solution is determined by the amount of peptide in the vial divided by the volume of water added. For example, if a vial contains 10 mg of peptide and you add 2 ml of bacteriostatic water, the resulting concentration is 5 mg/ml. Every 1 ml drawn from the vial will contain 5 mg of peptide.

The amount of water you add is flexible. Adding less water creates a more concentrated solution (requiring smaller injection volumes), while adding more water creates a more dilute solution (allowing for finer dose adjustments). The total amount of peptide in the vial remains the same regardless of how much water is added.

Reading an Insulin Syringe

Insulin syringes are calibrated in "units" rather than milliliters. A standard U-100 insulin syringe holds 1 ml of liquid, divided into 100 units. This means:

• 100 units = 1 ml
• 50 units = 0.5 ml
• 10 units = 0.1 ml
• 1 unit = 0.01 ml

To calculate how many units to draw for a given milligram dose, divide the desired dose (in mg) by the concentration (in mg/ml), then multiply by 100. For example, if you need 0.25 mg from a 5 mg/ml solution: (0.25 / 5) x 100 = 5 units.

Important Considerations

Sterile technique: Reconstitution should always be performed under clean conditions. Wipe the vial stopper with an alcohol swab before piercing it. Use a new, sterile syringe and needle each time you draw from the vial.

Bacteriostatic water vs. sterile water: Bacteriostatic water contains 0.9% benzyl alcohol, which inhibits microbial growth and allows the reconstituted peptide to be used for multiple draws over several weeks. Sterile water for injection has no preservative and should generally be used for single-use preparations only.

Storage after reconstitution: Once reconstituted, peptide solutions should be stored in the refrigerator (2-8 degrees Celsius). Avoid freezing the reconstituted solution, as this can damage the peptide structure. Most reconstituted peptides prepared with bacteriostatic water maintain stability for up to 4 weeks when properly refrigerated, though this varies by peptide.