L-carnitine is an amino acid your body produces naturally and also gets from food—mainly meat, fish, and dairy. It plays a role in moving fatty acids into your cells' mitochondria, where they're burned for energy. People take L-carnitine supplements for different reasons: some want to support workout performance and recovery, others are interested in its potential role in heart health or brain function, and some use it because they have a documented deficiency. Understanding what L-carnitine actually does, where it comes from, and whether supplementing makes sense for your situation requires looking past marketing claims.
These guides cover the practical questions: how L-carnitine works in your body, what the research actually shows about its effects on exercise and metabolism, how to choose between different forms (like L-carnitine tartrate or acetyl-L-carnitine), what dose people typically use, and what side effects or interactions you should know about. You'll also find information about food sources, who might benefit most from supplementing, and how to tell if it's making a real difference for you.