L Carnitine 340 mg Pure Encapsulations Blue Sky Vitamin Amino Acids Kidney Health L CARNITINE 510mg L Carnitine capsules 2 Bottles eBay History of L carnitine: Implications for renal disease Journal of Renal Nutrition 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. L carnitine is a naturally occurring amino acid structure that is made in the human brain, liver, and kidneys. L carnitine plays a critical role in energy production, as it converts fat into energy.