Small aggregates of proteins known as Aβ oligomers are suspected as the main cause for the development of Alzheimer’s disease. However, it is not yet clear where and under what conditions these toxic aggregates form. Researchers from Heinrich Heine University Düsseldorf and Forschungszentrum Jülich, together with partners from the University and University Hospital Cologne, have now found that a slightly acidic milieu is conducive to this development. In this environment, the oligomers form around 8,000 times quicker than for a neutral pH, as the scientists write in the journal Nature Communications. Such a slightly decreased pH also can be found in certain substructures of nerve cells.