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 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 Does L Carnitine Cause Heart Problems? L Carnitine Benefits: A Complete Research Based Guide Essential L Carnitine Optimal Health Systems