SAMe is not a medicine, drug, amino acid or vitamin, but a natural substance that plays many essential roles in the body. Under normal conditions, it is manufactured in abundance from methionine and adenosine triphosphate (ATP) and can be supplemented. It is essential for the production of the important antioxidant glutathione, especially in the liver and brain, and contributes to many of the body's essential physiological processes by acting as a methyl donor. Among its functions are the production and recycling of chemical signaling molecules, such as hormones and neurotransmitters, including serotonin, dopamine and noradrenaline, as well as methylation, the process of adding methyl groups that contributes to gene expression. In addition, SAMe modifies important molecules in cell membranes, controlling vital communication between and within cells.<\/p>\n\n\n\n