Citrulline malate is a supplement form of l-citrulline, an essential amino acid found in foods such as watermelon. This supplement is common in the bodybuilding community because it is thought to decrease body fat and promote release of human growth hormone and increased muscle mass. These claims have not been scientifically proven; however, clinical trials indicate that citrulline malate might have several health benefits.
Research suggests that citrulline malate might promote cardiac benefits in patients with certain types of heart failure. According to a small, two-month study published in 2010 in "Cardiology Journal," administration of citrulline improved the participants' overall heart function and lowered blood pressure. The researchers said that additional study on these effects is needed in a larger group of people over a longer amount of time.
Citrulline malate might also be beneficial in maintaining muscle strength and preventing muscle breakdown. According to results of an animal study published in 2009 in the "European Journal of Pharmacology," administration of citrulline malate limited skeletal muscle breakdown in the presence of a bacterial toxin. Researchers induced muscle weakness in rats by administering Klebsiella pneumoniae, a bacterial toxin. Citrulline malate blocked the toxic properties of the bacteria and maintained the integrity of skeletal muscle. More research is needed to determine whether the same effects would occur in humans.
Research suggests that citrulline malate might help fight fatigue. A human/animal study published in 1991 in the journal "Arzneimittelforschung" showed that the presence of this amino acid stimulated the liver and kidney to rid the body of toxins, providing protection against ailments such as acidosis. Acidosis -- a buildup of acid in the body -- is characterized by rapid breathing, confusion and excessive fatigue. Treatment with cirulline malate seemed to protect against this condition.