Citrulline

About Citrulline

Citrulline is a non protein amino acid, meaning it is not incorporated into proteins during translation. It was first isolated from watermelon, from whose Latin genus name Citrullus it takes its name, and watermelon remains one of the richest food sources, especially the rind. In the body citrulline is an intermediate of the urea cycle in the liver and is also produced in the intestine, then converted to arginine mainly in the kidneys. Because oral citrulline largely escapes breakdown in the gut and liver, it raises blood arginine levels more effectively than arginine itself, which has made it of interest as an indirect way to support nitric oxide production. It is sold as L citrulline or citrulline malate and studied for exercise performance, muscle soreness, blood pressure and erectile function, with mixed results. Plasma citrulline is also used in research as a marker of functional intestinal mass, and citrullinemia is a rare inherited urea cycle disorder.