Benefits of Acetyl L Carnitine Simply Supplements L Carnitine Linus Pauling Institute Oregon State University L Carnitine The Wonder Fat Loss Miracle or Just Marketing Hype? FIT Asia Advancing Fitness Education 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. Effect of Acute and Chronic Oral l Carnitine Supplementation on Exercise Performance Based on the Exercise Intensity: A Systematic Review