When to take L carnitine: Dosage, forms, and side effects Understanding the Role of Carnitine in TPN and IDPN Therapy KAL Acetyl L Carnitine and Alpha Lipoic Acid Tablets, 60 ct Smith's Food and Drug 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