Citrulline is a non-protein amino acid with the chemical formula C6H13N3O3. It is produced naturally by the body as a byproduct of the urea cycle, which is responsible for removing ammonia from the body. Measurement of citrulline is included in the Amino Acids, Plasma and Amino Acids, Urine tests along with 23 other amino acids.
Citrulline is also found in some foods, particularly watermelon, and is sometimes used as a dietary supplement. It is marketed as a sports supplement due to its potential role in improving athletic performance and reducing muscle fatigue.
Citrulline has been studied for its potential health benefits in a variety of areas, including cardiovascular health, erectile dysfunction, and exercise performance. It is believed to help improve blood flow by increasing levels of nitric oxide, which is a vasodilator that can widen blood vessels and improve circulation.
Research has also suggested that citrulline may help improve exercise performance and reduce muscle fatigue by increasing the production of ATP, a key energy source for muscles. It may also help reduce muscle soreness and improve recovery time after exercise. Overall, while more research is needed to fully understand the potential health benefits of citrulline, it is a fascinating molecule with a range of potential applications in sports nutrition, cardiovascular health, and more.
Citrulline can also serve as a biomarker in plasma and urine for various diseases and conditions.
Low levels of citrulline in plasma have been associated with poor prognosis in patients with various diseases, including liver disease, sepsis, and cancer. In liver disease, for example, low plasma citrulline levels have been associated with more severe liver damage and increased mortality.
Citrulline levels in urine have also been studied as a potential biomarker for various conditions. For example, urinary citrulline levels have been found to be decreased in patients with inflammatory bowel disease, indicating that it may be useful as a marker for disease activity and severity.