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. Carnitine: Genetic Variants Affecting Mitochondrial Energy and Health Benefits of Acetyl L Carnitine Simply Supplements L carnitine supplementation for the management of fatigue in patients with hypothyroidism on levothyroxine treatment: a randomized, double blind, placebo controlled trial. Semantic Scholar ACETYL L CARNITINE 500 mg