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 L carnitine Liquid Energy Support for Workout Performance Enhanced Bioavailability of L Carnitine After Painless Intradermal Delivery vs. Oral Administration in Rats Pharmaceutical Research Springer Nature Link L carnitine modified nanoparticles target the OCTN2 transporter to improve the oral absorption of jujuboside B ScienceDirect CARNITOR (levocarnitine) Oral Solution (1 g per 10 mL multidose)