Want your edge back? Apparently, a best-selling brain supplement on Amazon could help. The trending nootropic has become popular with a wide range of users — from medical students and nine-to-fivers to self-proclaimed “super moms,” and even older employees who admit they needed a bit of a brain boost to keep up with the competition. “I’m still working and find I need an ‘edge’ to compete with my younger co-workers,” one reviewer wrote. “I’ve tried many of the available supplements and have