The present invention relates to a method for identifying an inhibitor of the aggregation of amyloid-β peptide (Aβ), comprising the steps of a) contacting at least one Aβ -peptide and/or the nitrated forms thereof with at least one candidate inhibitor that potentially specifically binds to a region in said Aβ -peptide capable of being nitrated, and b) detecting said inhibitor specifically binding to said region in said Aβ -peptide through detecting a lack of or a reduced aggregation of said at least one Aβ -peptide. The present invention is further directed at improved methods for treating neuronal degradation and particularly Alzheimer's disease, based on said inhibitor. The present invention is further directed at methods for diagnosing the aggregation of Aβ -peptide in the context of neuronal degradation and particularly Alzheimer's disease.