Phosphatidylserine (PS) derived from bovine brain phospholipids has been shown to improve memory, cognition, and mood in the elderly in at least two placebo-controlled trials. In both trials, geriatric patients received 300 mg per day of PS or placebo. In an unblinded trial of ten elderly women with depressive disorders, supplementation with PS produced consistent improvement in depressive symptoms, memory, and behavior after 30 days of treatment.¹ A double-blind trial of 494 geriatric patients with cognitive impairment found that 300 mg per day of PS produced significant improvements in behavioral and cognitive parameters after three months and again after six months.²

Most research has been conducted with PS derived from bovine tissue, but what is available commercially is made from soy. The soy- and bovine-derived PS, however, are not structurally identical.³Doctors and researchers have debated whether the structural differences could be important,^{4 , 5} but so far only a few trials have studied the effects of soy-based PS.

Preliminary animal research shows that the soy-derived PS does have effects on brain function similar to effects from the bovine source.^{6 , 7 , 8} An isolated, unpublished double-blind human study used soy-derived PS in an evaluation of memory and mood benefits in nondemented, nondepressed elderly people with impaired memories and accompanying depression.⁹ In this three-month study, 300 mg per day of PS was not significantly more effective than a placebo. In a double-blind study, soy-derived PS was administered in the amount of 300 or 600 mg per day for 12 weeks to people with age-related memory impairment. Compared with the placebo, soy-derived PS had no effect on memory or on other measures of cognitive function.¹⁰While additional research needs to be done, currently available evidence suggests that soy-derived PS is not an effective treatment for age-related cognitive decline