It is a chromatographic area percentage
Purity is the area of the main HPLC peak as a proportion of total detected peak area. It describes the relative abundance of the main species among everything the detector saw.
What it does not include
It says nothing about water content, residual salts, or counter-ion mass. A vial can be 99.5% pure by HPLC while a portion of its net weight is trifluoroacetate salt and bound moisture — which is why peptide content is reported separately.
Comparing suppliers honestly
Only compare purity figures produced by the same method at the same wavelength. A figure with no method stated is not comparable to anything.
Research use only
All materials referenced here are supplied by Aura Peptide Co. strictly for in-vitro laboratory and research use. Nothing on this page is guidance for human or animal use.