Understanding the Role of Carnitine in TPN and IDPN Therapy PDF) The Role of L Carnitine in Kidney Disease and Related Metabolic Dysfunctions Most people talk about carnitine like it is one supplement. It is not. Acetyl L carnitine and L carnitine L tartrate do different jobs, and picking the wrong one for the wrong goal is where people Is it safe for a patient with a history of kidney transplant to receive carnitine and NAD (Nicotinamide adenine dinucleotide) IV therapy? 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.