L-Carnitine is an amino acid that acts as a building block for proteins. Your body produces it naturally in the liver and kidneys, storing it in your muscles, brain, heart, and sperm. L-Carnitine helps convert fatty acids into usable energy. Its main role is to transport fat into our cells’ mitochondria, where fatty acids are broken down and converted into ATP energy, which can be used to power our muscles during exercise, as well as fuelling many other cellular processes.