Sharp-PS Green. Phosphatidylserine (PS) is a phospholipid that is a structural component of cell membranes. It is an important phospholipid present in the brain and supports brain health. Jarrow Formulas PS100, featuring Sharp-PS, utilizes a concentrated form of phosphatidylserine from sunflower lecithin (soy-free) that offers excellent stability. Note: Color may vary from batch to batch.