L-Citrulline is an amino acid that is made natural by the body. Once consumed your body converts it to a different amino acid called L-Arginine. L-Citrulline may actually be more effective at boosting L-Arginine levels due to the poor bioavailability of L-Arginine. Once L-Citrulline is converted to L-Arginine, it helps synthesize and boost levels of Nitric Oxide which help with blood flow and circulation. Research also suggests L-Citrulline may reduce fatigue and improve exercise endurance. It also supports reduced muscle soreness following workouts and cardiovascular health. The recommended dose is 1,200 - 2,400 mg taken per day for circulatory support. To enhance sports performance take 6,000mg approximately 1 hour before exercise. Double Wood Supplement?s L-Citrulline is produced and tested right here in the USA.