Carnitine is a compound naturally produced in the body, primarily in the liver and kidneys, from the amino acids lysine and methionine. It plays a vital role in energy metabolism by transporting fatty acids into the mitochondria, where they are oxidized and converted into energy.

Carnitine is available in various forms, including L-carnitine, acetyl-L-carnitine, and propionyl-L-carnitine, each with slightly different properties and potential benefits. L-carnitine is the most common and well-known form.

Supplementing with carnitine is often done by athletes and individuals seeking to enhance exercise performance, promote fat burning, and support recovery. It is believed to increase the utilization of fatty acids as a fuel source during exercise, which may help preserve glycogen stores and delay the onset of fatigue. Additionally, carnitine has been suggested to have antioxidant and neuroprotective effects.