Most oral L carnitine supplements are glorified flavored chemical waters., , Low bioavailability = very little of it actually gets picked up for use by the body., , So when companies sell $40$60 L Carnitine Injections for Weight Loss Low Bioavailability and High TMAO Production: Novel Insights Into Acetylcarnitine and Carnitine Metabolism KrimsDavis 2025 Molecular Nutrition & Food Research Wiley Online Library 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