Carnitine: the claims and why it may not work Carnitine: Genetic Variants Affecting Mitochondrial Energy and Health Effects of l Carnitine Supplementation in Patients Receiving Hemodialysis or Peritoneal Dialysis 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