A dry or lyophilized peptide does not just contain the peptide by itself.
Lyophilized peptides can contain other components such as water, traces of solvents, ammonium, potassium and sodium ions, other ions, and salts.
The net peptide content refers to the actual content of the peptide, which is the percent weight of the peptide from the gross weight.
This peptide content may vary from 50 to 90 percent, depending on the purity, sequence, and method of synthesis and purification.