Injectable vs Oral L Carnitine: Which Works Better? AWP Revisiting the Role of Carnitine in Heart Disease Through the Lens of the Gut Microbiota Carnitine: the claims and why it may not work The bright and the dark sides of L carnitine supplementation: a systematic review Journal of the International Society of Sports Nutrition Springer Nature Link 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