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. L Ornithine L Aspartate Pure Prescriptions Early research into L carnitine was often cited as underwhelming, showing negligible changes in muscle carnitine content and fat loss outcomes. However, these findings may have been limited by a short study window Evaluation of the effects of L carnitine on medaka (Oryzias latipes) fatty liver Scientific Reports Scientifically Backed Triple Strength L Carnitine NOW Foods L Carnitine Linus Pauling Institute Oregon State University