L-carnitine can be found in the diet or produced from lysine and methionine in the liver and kidney. The enzyme carnitine acetyltransferase converts L-carnitine into acetyl-L-carnitine. Higher levels of acetyl-L-carnitine (ALCAR) increase acetylcholine GABA, and glutamate in the brain. As brain cells age, inflammation increases, and neurons become less functional. ALCAR is thought to support acetylcholine levels in the brain. L-carnitine is also transported via the bloodstream to skeletal muscle and the heart, organs that rely on L-carnitine to oxidize fatty acids for energy. The bioavailability of ALCAR is thought to be higher than L-carnitine. When humans ingested 2 grams/day for 50 days, plasma ALCAR concentration increased by 43%. ALCAR may improve energy for use in muscle cells and support cardiovascular health.