L Carnitine Uses & Benefits Explained: A Complete Guide The Science of Good 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 Carnitine supplementation promotes fat loss Meta study L Carnitine Assay Kit Efficacy of L carnitine supplementation for improving lean body mass and physical function in patients on hemodialysis: a randomized controlled trial European Journal of Clinical Nutrition