Ashwagandha KSM-66 has a more rigorous clinical evidence base than almost anyone in the nootropic community appreciates — including a trial showing 27.9% cortisol reduction with direct serum measurement and across-the-board cognitive improvements in healthy adults at 8 weeks. After 18+ years of research, here is the complete evidence-based guide to the stress substrate compound that determines how well everything else in the protocol performs.