Put your thinking cap on with Jarrow Formulas Phosphatidylserine PS100. As an essential component of cell membranes, phosphatidylserine (PS) helps support neuronal health and communication. This promotes cognition, attentiveness and reaction time. It may also reduce the action of the stress hormone cortisol. Each serving delivers 100 mg phosphatidylserine as Cogni-PS, a concentrated formulation designed for better stability.