If you're regularly involved in strenuous exercise or are concerned about your cardiovascular health, you might find a supplement called L-citrulline malate of potential value. Citrulline is an amino acid that's considered nonessential because your body makes a sufficient supply and dietary intake isn't essential.
Modern research suggests that L-citrulline malate, the chemical form of citrulline available as a supplement, can boost energy and may help lower your risk of certain chronic problems.
Enhanced Exercise Tolerance
Research on the body's usage of citrulline during exercise suggests that consuming a citrulline supplement might enhance performance. A study published in 2011 in the "Journal of Nutritional Science and Vitaminology" reported that laboratory animals fed citrulline and subjected to intense exercise were able to perform longer and also had lower levels of blood ammonia and lactate, two waste compounds produced during exercise, than a placebo group.
In a small clinical study published in the September 2010 issue of the "European Journal of Applied Physiology," researchers found that male cyclists who took citrulline two hours before exercise had blood markers indicating improved use of amino acids by their tissues, compared to a control group. These promising results are preliminary, however, and still need confirmation in larger clinical trials.