phosphatidylserine 300mg per serving, made in the usa, 120 capsules (phosphatidyl serine complex) by double wood supplements double wood supplements phosphatidylserine (ps – phosphatidyl serine) is a phospholipid and a component of the cell membrane. it plays a key role in cell cycle signaling, specifically in relationship to apoptosis. studies have provided evidence that ps may support attention, memory, processing speed, and overall cognitive health. effects were most pronounced in those who were already fatigued. double wood supplement’s ps is manufactured in new york city and tested for purity right here in the usa