Peptide Reconstitution Math: Concentration Calculator
Concentration describes how much material is present in a volume of solution. Enter a mass and the final volume to see the same concentration in milligrams and micrograms per milliliter.
Enter a mass and final volume to calculate concentration.
How the calculation works
Concentration equals mass divided by final solution volume. For example, 12 mg in a final volume of 4 mL is 3 mg/mL, or 3,000 mcg/mL. One milligram equals 1,000 micrograms. The two answers describe the same solution using different mass units.
Final volume and added liquid are different quantities
The denominator is the final volume of the solution. It is not automatically the amount of liquid added to a powder. A product's preparation instructions account for its formulation and specify how the final concentration is obtained.
What happens when the volume changes?
If the mass stays constant and the final volume doubles, the concentration halves. A larger volume would then contain the same mass that a smaller volume contained before dilution. Adding liquid does not make a fixed mass fit into a smaller volume.
Concentration is not a dose
A concentration states mass per volume. A prescribed dose, a measuring device's markings, and a preparation instruction are separate pieces of information. This calculation does not determine a treatment amount or establish whether a substance is appropriate to administer.
Why there is no universal peptide preparation rule
Solvent, storage temperature, and usable time depend on the exact formulation. Even Egrifta WR and Egrifta SV, two products containing tesamorelin, have different preparation and storage instructions and are not substitutable. A generic 28-day refrigerated-storage rule cannot replace a product's instructions.
Source: FDA prescribing information for Egrifta WR, section 2.
