Is L Carnitine safe for athletes at doses up to 6000 mg day? Consensus The bright and the dark sides of L carnitine supplementation: a systematic review Journal of the International Society of Sports Nutrition Springer Nature Link L Carnitine Side Effects & Safety: A Complete Guide The Science of Good Health What is carnitine? Carnitine is produced in the body from the amino acid lysine and naturally occurs in some foods. It supports energy metabolism and muscle function, which are important factors in