Phosphatidylserine (PS) is a natural nutrient found in the brain. Phosphatidylserine is the major phospholipid in the brain where it plays a major role in determining the integrity and fluidity of cell membranes. Healthy cell membranes support healthy brain functions such as memory, focus and clarity. Natural Factors is naturally derived from soy phospholipids. In clinical studies, plant-based PS is just as effective as animal-based PS with none of the concerns associated with prion diseases (i.e. Mad Cow disease). Clinical studies on humans verify PS safety.