The bright and the dark sides of L carnitine supplementation: a systematic review Journal of the International Society of Sports Nutrition Springer Nature Link L Carnitine Benefits: A Complete Research Based Guide L Carnitine: The Energy Booster Your Body Loves Turn fat into fuel and power up your recovery with one of our favorite performance vitamins. Boosts metabolism & fat burning 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 L Carnitine