Aβ tauaggregation-IN-1 is a potent inhibitor of Aβ 1-42 β-sheet formation and tauaggregation. It exhibits K D values of 160 μM and 337 μM with Aβ 1-42 and tau, respectively. Additionally, Aβ tauaggregation-IN-1 can penetrate the blood-brain barrier efficiently.