The Synergistic Effects of the Combination of L Carnitine and Lycopene on the Lycopene Bioavailability and Duodenal Health of Roosters L carnitine is effective for both fat loss and athletic performance. However, oral L carnitine has lower bioavailability and can be harmful at high doses, so it should be avoided. , Even cardiologists What is L Carnitine, L Carnitine is an amino acid that plays a role in energy production and fat metabolism. Its found in foods like red meat, fish, and dairy, and also available as a supplement., Acetyl L Carnitine Study NOW Foods