In one of the few human studies, researchers examined the effects of supplementation with six grams of citrulline malate daily for 15 days [1].
The results show that citrulline malate led to a significant reduction in the sensation of fatigue, a 34% increase in the rate of oxidative ATP production during exercise, and a 20% increase in the rate of phosphocreatine recovery after exercise. This indicates a larger contribution of oxidative ATP synthesis to energy production.
1. Bendahan, D., Mattei, J.P., Ghattas, B., Confort-Gouny, S., Le Guern, M.E., & Cozzone, P.J. (2002). Citrulline/malate promotes aerobic energy production in human exercising muscle. British Journal of Sports Medicine, 36, 282-289