The name citrulline is derived from citrullus, the Latin word for watermelon, from which it was first isolated in 1930. Citrulline Malate is a combination of the amino acid Citruline, which is involved in the urea cycle and Malate, a tricarboxycylic acid cycle (TCA) intermediate. The TCA cycle is a major producer of aerobic energy within the mitochondria. Citrulline Malate has many positive effects on aerobic exercise performance including increased aerobic production of energy, improved stamina and fatigue resistance, and improved recovery and energy levels.
Citrulline is naturally produced in small quantities from the amino acid L-glutamine, and can be converted by our body to arginine. Supplementation with citrulline malate has been demonstrated to increase levels of arginine and ornithine which are both important for muscle growth and have been shown to influence growth hormone levels. Arginine has many important roles within the body such as the production of nitric oxide, which helps to increase blood flow and oxygen delivery to muscles, and also increasing the rate of muscle growth. Malate is believed to enhance the level of ATP (energy molecules) production through aerobic metabolism.
Citrulline malate has been used to assist in improving recovery from physical activity in patients with acute diseases. Research has demonstrated that citrulline malate has a protective effect against increased blood acidity and ammonia poisoning. Supplementation with citrulline malate increases the rate of ammonia clearance without affecting ammonia accumulation during bicycle exercise. This is because citrulline is involved in the urea cycle and therefore plays a role in the detoxification of ammonia.
Supplementation with citrulline malate has been shown to increase levels of bicarbonate (an acid buffer that soaks up lactic acid molecules). This may allow exercise at a higher level before the negative effects of increased acidity affect exercise performance.
Research by Benedahan et al., 2002, showed the potential forcitrulline malate supplementation to enhance aerobic performance. Significantly more energy was produced aerobically (around 34%), but there was also a significant reduction in fatigue. The study found that rate of recovery, as measured by the rate of phospho-creatine recovery, improved by 20%. The researchers concluded that the increased aerobic ATP production, together with a reduced proportion of anaerobic energy supply, may contribute to the lower levels of fatigue experienced by the subjects.