When to Take L Carnitine for Optimal Training Benefits Transparent Labs 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 Frontiers Association between fatigue, peripheral serotonin, and L carnitine in hypothyroidism and in chronic fatigue syndrome Dietary sources of choline, phosphatidylcholine, and L carnitine Download Scientific Diagram