Citrulline Improves Performance

Cyclists consuming 2.4 grams of citrulline per day for eight days improved performance on a four-kilometer cycling speed trial by 1.5 percent, compared to a placebo (fake citrulline). The cyclists reported less fatigue and improved mental concentration after the ride. Citrulline is an amino acid that is converted to arginine, which increases levels of nitric oxide— an important chemical that regulates blood flow throughout the body. Nitric oxide is an important marker of metabolic health and is essential for well-being, sexual performance and overall energy levels. Citrulline supplements can reduce blood pressure in people with hypertension and can increase muscle blood flow. The effects on performance are small, so the practical value of this supplement is questionable. (Journal of the International Society of Sports Nutrition, published online February 20, 2016)