GSK3β Inhibitor II is a potent inhibitor of glycogen synthase kinase-3β (GSK3β; IC50 = 390 nM) that does not inhibit GSK-3α. Also referred to as tip-oxadiazole, this compound blocks the functional regulation of p53 by GSK3β, decreasing levels of MDM2, p21, and Bax and modulating mitochondrial p53 apoptotic signaling. GSK3β Inhibitor II also blocks GSK3β-mediated Tau phosphorylation and Aβ25-35-induced memory impairment in mouse hippocampus.