How Much L Carnitine Per Day: Expert Guide The Science of Good Health Ultra L Carnitine NutriRestore Frontiers A randomized clinical trial to evaluate the efficacy of L carnitine L tartrate to modulate the effects of SARS CoV 2 infection If you are like a lot of people, you may have never heard of carnitine but this important nutrient is critical for our body's ability to optimally burn fat required for energy.