What is citrulline malate and what does it do?
Citrulline is a non-essential amino acid and plays a role in nitrogen balance and metabolic processes. Although not a component of most proteins in the body, citrulline is found in some specialized proteins in the hair, skin and neural cells. It is primarily synthesized from glutamine in the intestines but is also found naturally in trace amounts in some foods.
Citrulline supplied by the diet is efficiently absorbed from the stomach and enters the blood via the major vein draining the digestive system that empties into the liver. Much of it bypasses uptake in the liver and is then circulated for distribution to the kidneys, brain, muscle and other tissues for conversion to arginine.
Supplemental citrulline malate is a salt form of the amino acid. The malate, or malic acid, is found in fruits such as apples and enhances the effects of citrulline. Malic acid takes part in aerobic cellular respiration where oxygen and a carbon compound (acetyl Co-A) are used to produce immediate energy and CO2 in the mitochondria of the cell. This is called the Kreb’s cycle. Malate conditions the recycling of lactate and pyruvate promoting efficient energy production and protecting muscles from fatigue.
How does citrulline malate benefit the athlete?
Citrulline malate improves aerobic performance and capacity by influencing lactic acid metabolism and reducing fatigue. Studies in Europe, where citrulline malate has been used for over 20 years, demonstrate reduction in mental and physical fatigue and exhaustion in geriatric and post-surgery patients. Laboratory studies with rats and microbes support the results seen in humans. Administration of citrulline malate to animals protected against acidosis and ammonia poisoning. In a microbial model, malate accelerated the clearance of ammonium and citrulline facilitated lactate metabolism. The results suggest a synergistic action of the complex.
Supplementation of citrulline malate to humans has shown promising results. French researchers reported in several human studies that blood lactate concentrations were reduced and ammonia elimination was increased after physical exertion. Rapid recovery from physical effort correlated to the disappearance of lactate from blood after performance at a high level of acidosis suggesting an essential role in acid-base balance.
Effects on metabolism in the finger flexor muscles after 15 days of citrulline malate supplementation were determined during exercise. Subject reports of significant reduction in fatigue were supported by an increase in the rate of oxidative ATP and energy production.
Two groups of basketball players were supplemented with citrulline malate for over 13 days with two different dosages. The group with the higher dosage had significant improvements in maximal workload during an exercise test on a cycle ergometer. Although fewer improved on the second maximal cycling test, the authors concluded that citrulline malate may improve aerobic performance.
