The Role of L Carnitine in Kidney Disease and Related Metabolic Dysfunctions L Carnitine vs L Arginine: Understanding Their Differences and Benefit Fitness Health Early research into L carnitine was often cited as underwhelming, showing negligible changes in muscle carnitine content and fat loss outcomes. However, these findings may have been limited by a short study window L carnitine reduces ammonia levels and alleviates covert encephalopathy: A randomized trial