L Carnitine Dosage for Erectile Dysfunction: What the Evidence Shows and How to Use It Safely L Carnitine Injection Levocarnitine IV PDF) Effects of switching from oral administration to intravenous injection of L carnitine on lipid metabolism in hemodialysis patients Injectable VS Liquid L Carnitine. Which is better? L Carnitine is often marketed as a fat burner, but most people dont realize that oral and injectable L Carnitine are not the same..Oral L Carnitine has poor absorption (only 20% bioavailability),