L Carnitine vs L Arginine: Understanding Their Differences and Benefit Fitness Health GNC Total Lean L Carnitine 1000 mg 60 Tablets GNC Semaglutide, a popular weight loss medication, was recently approved by the U.S. Food and Drug Administration in pill form. Until now, weight loss medications like this have only been available as injections, L Carnitine: Benefits, Side Effects, And Dosage, Per Dietitians 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 give IV