L carnitine is primarily synthesized in the liver from the amino acids lysine and methionine through a series of four enzymatic reactions, with the liver and kidneys converting the precursor butyrobetaine into active My 4 month old girl Margo was diagnosed with polyneuropathy last week. Neurologist has recommended L carnitine as a supplement. She's better than she was but not climbing or jumping yet x L Carnitine Deficiency in Cats Symptoms, Causes, Diagnosis, Treatment, Recovery, Management, Cost Dietary l Carnitine Supplementation in Obese Cats Alters Carnitine Metabolism and Decreases Ketosis during Fasting and Induced Hepatic Lipidosis ScienceDirect L Carnitine Deficiency in Cats PetMD