Phosphatidylserine (PS) is a naturally occurring phospholipid compound that plays important roles in neurotransmitter function and in maintaining the structural integrity of brain cell membranes. Although the brain is normally able to manufacture sufficient PS on its own, this process can be impaired by deficiencies in B vitamins or essential fatty acids. Found only in trace amounts in the typical diet, PS is available as a dietary supplement. Supplemental PS, which was originally extracted from cattle brains, is now manufactured from soy lecithin.
Most human studies on phosphatidylserine have used 300 mg per day, usually divided into three 100 mg doses. PS has very low toxicity and appears to be well tolerated at this dosage level.