- L-Carnitine is a compounded amino acid for injection. It assists with fatty acid metabolism and weight control; myocardial infarction protection; promotes cellular energy; reduces fatigue; and may also be good for circulation disorders. This amino acid is required for the transport and breakdown of body fat for the generation of metabolic energy. Oral supplementation can decrease fat mass, preserve muscle during exercise, and reduce muscle fatigue. It is an important regulator of skeletal muscle fuel selection and is needed to determine whether muscle tissue utilizes carbohydrates or fat for energy. When taken orally, L-Carnitine requires a high dose to promote fat tissue breakdown. Only a fraction of L-Carnitine is absorbed during oral digestion. When administered by injection, nutrients like carnitine are completely absorbed by the body.