L Carnitine for Fat Burning: How It Really Works (Without the Hype) Is L Carnitine the Key to Fat Loss? Protyze sixpacknutrition How L Carnitine helps in Burning Fat? Read the caption Most people believe steroids, fat burners, or L Carnitine melt fat. The truth is different. Steroids mainly increase muscle protein synthesis and help maintain muscle mass, but they do Trying to Burn fat? You need Acetyl L Carnitine.