Phosphatidylserine (PS) is a natural component of many cell membranes. Supplementation with PS has been shown to reduce mental stress and even the stress response to exercise. Some research suggests that it may function as an antioxidant as well. A study published in the August issue of Medicine and Science in Sport and Exercise examined PS supplementation in soccer players. The subjects supplemented with PS (750 mg/day) or placebo for 10 days. Before and after the supplementation period, subjects performed an intense exercise protocol consisting of intermittent high-intensity activities for a total of 90 min culminating in a test to volitional fatigue as a measure of performance. The main effect of PS supplementation was to increase blood levels of gamma tocopherol, which could potentially augment antioxidant defense. There was also a trend for improved performance. Performance was increased by 4.2% with PS supplementation and decreased by 3.7% in the placebo group. The study provides evidence of an ergogenic effect of PS supplementation on exhaustive running.

Kingsley MI, Wadsworth D, Kilduff LP, McEneny J, Benton D. Effects of phosphatidylserine on oxidative stress following intermittent running. Med Sci Sports Exerc. 2005 Aug;37(8):1300-1306.