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 Carnitine Shuttle an overview ScienceDirect Topics Carnitine Transport in Mitochondria Boosts Energy Science Magazine posted on the topic LinkedIn Frontiers Dietary supplementation with L carnitine elevates intracellular carnitine levels and affects gene expression of SLC25A20 and COX4I1, as well as non mitochondrial respiration of bovine blood cells during systemic immune challenge