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. Acetyl L Carnitine from Your Wellbeing VitaGene Thorne Acetyl L Carnitine Dietary Supplement, 500 mg l Carnitine and Acetyl l carnitine Roles and Neuroprotection in Developing Brain Neurochemical Research Springer Nature Link