Dietary Supplement Non-GMO Soy Free PS Factor® The Key to Brain Health Sharp - PS Green Purity & Potency GuaranteedPhosphatidylserine (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.