Influence of L-citrulline and watermelon supplementation on vascular function and exercise performance

Purpose of review L-citrulline, either synthetic or in watermelon, may improve vascular function through increased L-arginine bioavailability and nitric oxide (NO) synthesis. This article analyses potential vascular benefits of L-citrulline and watermelon supplementation at rest and during exercise. Recent findings There is clear evidence that acute L-citrulline ingestion increases plasma L-arginine, the substrate for endothelial NO synthesis. However, the subsequent acute improvement in NO production and mediated vasodilation is inconsistent, which likely explains the inability of acute L-citrulline or watermelon to improve exercise tolerance. Recent studies have shown that chronic L-citrulline supplementation increases NO synthesis, decreases blood pressure (BP), and may increase peripheral blood flow. These changes are paralleled by improvements in skeletal muscle oxygenation and performance during endurance exercise. The antihypertensive effect of Lcitrulline/watermelon supplemen