A Beginner's Guide to L Carnitine Bulk Acetyl L Carnitine 120 1000 mg acetyl L carnitine per daily dose; Increase energy and stamina during physical activity; Supports mental function, improving concentration and memory; Ideal for Acetyl L. Carnitine Supplement Metabolics 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