Molar mass
In short The mass of one mole of the substance, in grams per mole (g/mol).
Molar mass is calculated by adding up the atomic masses of every atom in the molecular formula. BPC-157, for example, has a molar mass of about 1419.55 g/mol. The term is often used interchangeably with molecular weight, and the value is the same number expressed in daltons for a single molecule.
In the laboratory, molar mass is what converts between mass and amount of substance. It is needed whenever a concentration is expressed in molar terms rather than in milligrams per millilitre, and when results from different peptides are compared on an equal-molecule basis.
It is also the reference value for identity testing. Mass spectrometry measures the mass of the actual molecules in the sample; if it agrees with the molar mass calculated from the formula, that supports the identity of the peptide.
Molar masses on UKPeps pages are given to two decimal places where available. Salt forms, such as the disodium salt of NAD+, have a different molar mass from the free form, and the page states which one applies.