L-carnitine is a compound produced in the body from lysine and methionine.[1][2] It is also found in food, primarily in meat products,[3][4] and can be taken as a supplement. L-carnitine can be acetylated to produce acetyl-L-carnitine (ALCAR), which is similar to L-carnitine but crosses the blood-brain barrier more efficiently.[5] L-carnitine is best known for its role in helping to ”shuttle” long-chain fatty acids into mitochondria to produce energy.[6][1]