Ultra L Carnitine NutriRestore L Carnitine Benefits, Side Effects & Dosage SelfDecode Supplements 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 not only for athletes. Effects and properties of L carnitine OstroVit Is L Carnitine safe for athletes at doses up to 6000 mg day? Consensus