S-Adenosyl Methionine (SAM-e) is derived from the amino acid methionine and is one of the most important methyl donors in the central nervous system. Methylation (donation of methyl groups) is an essential process in ensuring the proper function of a number of organ systems. Methylation occurs billions of times daily in the many organs of the body. SAM-e is involved in numerous biochemical reactions in tissues including the liver, joints and brain. SAM-e is also required for the biosynthesis of critical neurotransmitters and hormones. SAM-e is the methyl donor that catalyzes the production of epinephrine, melatonin, glutathione and the amino acids cysteine and taurine. SAM-e is also known to upregulate the production of critical membrane phospholipids including phosphatidylcholine. SAM-e is also a sulfur donor and, for this reason, is critical for the formation of sulfur-containing proteoglycans in joint connective tissue