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 Effect of L carnitine on quality of life in covert hepatic encephalopathy: a randomized, double blind, placebo controlled study Carnitine Deficiency: What Is It, Causes, Symptoms, and More Osmosis Acetyl L carnitine in chronic pain: A narrative review ScienceDirect