Medium chain fatty acid oxidation is independent of l carnitine in liver and kidney but not in heart and skeletal muscle American Journal of Physiology Gastrointestinal and Liver Physiology American Physiological Society 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 Liquid L Carnitine Energy, Metabolism & Fat Burning Systemic regulation of L carnitine in nutritional metabolism in zebrafish, Danio rerio Scientific Reports