L Carnitine Linus Pauling Institute Oregon State University Is L Carnitine safe for athletes at doses up to 6000 mg day? Consensus The Role of L Carnitine in Kidney Disease and Related Metabolic Dysfunctions L carnitine is a naturally occurring amino acid structure that is made in the human brain, liver, and kidneys. L carnitine plays a critical role in energy production, as it converts fat into energy. Acetyl L Carnitine is more thought of as a fat burner. It's actually powerful tool for athletes looking to improve endurance, energy, and mental performance. Here's how you can integrate it into your routine for