L Carnitine is an amino acid found in high concentrations in muscle, heart, and liver tissues. Inside the cells, L Carnitine transports fatty acids into the mitochondria for energy production (i.e., ATP) and reduces ACETYL L CARNITINE Transports Fatty Acids Boosts Cellular Energy (2 bottles) eBay 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 PDF) Role of Carnitine in Non alcoholic Fatty Liver Disease and Other Related Diseases: An Update