BIO-acetoxime (GSK-3 Inhibitor X) is a highly potent and selective dual inhibitor of GSK3alpha and GSK3beta, exhibiting an IC50 of 10 nM. It demonstrates significant selectivity, being over 240-fold more potent against GSK3 than against related kinases CDK5/p25, CDK2/cyclin A, and CDK1/cyclin B. This inhibitor is a valuable research tool for studying GSK3 signaling in neurological disorders and cellular models both in vitro and in vivo.