A standard dosage of phosphatidylserine (PS) is 300 mg daily, divided into 3 doses of 100 mg each. This dosage seems to be effective as a daily preventative against cognitive decline, and 100 mg once daily may provide some degree of benefit (but might be less beneficial than 300 mg).

Studies in children and adolescents for the purpose of attention improvement tend to use 200 mg, and a dose of 200–400 mg has been used in adult non-elderly humans with success. Animal evidence tends to use a dose correlating to 550mg as well.