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 Understanding the Role of Carnitine in TPN and IDPN Therapy Understanding the Role of Carnitine in TPN and IDPN Therapy What Is Acetyl L Carnitine Good For? Uses & Benefits If you are like a lot of people, you may have never heard of carnitine but this important nutrient is critical for our body's ability to optimally burn fat required for energy.