L Carnitine The leading ingredient in any energy drink is usually caffeine. Most of them contain herbs, caffeine, and other substances. Many energy drink brands claim to be supplements. The FDA doesn't approve energy Liquid L Carnitine 3000: Metabolism & Energy Support Cutler Nutrition Premium L Carnitine (30 SERVINGS) by REDCON1 Did you know L carnitine, a vital amino acid, is naturally produced by your body and found in various foods? While acetyl L carnitine (ALCAR) can be a beneficial supplement for some, most people get Did you know L carnitine, a vital amino acid, is naturally produced by your body and found in various foods? While acetyl L carnitine (ALCAR) can be a beneficial supplement for some, most people get