Citrulline is an essential amino acid that participates in the formation of urea. It’s a popular component in athletic food supplements because it’s involved in key amino acid reactions and effects blood flow by increasing nitric oxide levels. Nitric oxide is an important chemical secreted by the endothelium – the inner lining of the blood vessels.
British researchers discovered that citrulline supplements (6g/day) accelerated oxygen uptake during exercise, improved resting blood pressure, boosted endurance performance and enhanced tolerance to high-intensity workout in healthy adults.
Watermelon rind is a great source of citrulline.