Dietary Supplement Non-GMO Soy Free PS Factor The Key to Brain Health Sharp• PS Green Purity & Potency Guaranteed Phosphatidylserine (PS) is a natural component of the brain and is integral to all brain cell activity. Supplementing the diet daily with PS supports healthy brain function. Natural Factors uses Sharp-PS GREEN Phosphatidylserine, which is derived from non-GMO sunflower lecithin and is 100% soy-free. All Natural Factors products are manufactured in accordance with the Government of Canada's Good Manufacturing Practices (GMP), among the highest standards in the world.