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 injection is recommended at 1 ampule every 2 3 days for best results. The L Carnitine is taken intravenously either by normal injection or using a butterfly needle. After taking this L Carnitine, you L carnitine for metabolism Lifehack How Much L Carnitine Should I Take? A Guide The Science of Good Health 5 Health Benefits of L Carnitine Carnitine: the claims and why it may not work