The Best L-Carnitine Supplement: The Cherry to Your ... Top L-Carnitine Reviews Evlution Nutrition Carnitine500. First on our list of the best L-carnitine supplements is Evlution's 500-mg serving capsules. With no added stimulants, this is pure L-carnitine; Evlution claims that these pills "support fat loss by converting stored body fat into energy while supporting workout performance and ...