Acetyl L Carnitine vs L Carnitine: 4 Key Differences Momentous Amazon.com: Carlyle L Carnitine Tartrate 2175mg 200 Capsules Advanced Athlete Formula Workout Supplement As L Carnitine L Tartrate Non GMO, Gluten Free : Health & Household High Strength Liquid L Carnitine 5000 Mg, 16 Oz (473 ML) eBay Early research into L carnitine was often cited as underwhelming, showing negligible changes in muscle carnitine content and fat loss outcomes. However, these findings may have been limited by a short study window