SAMe is a supplement formed in the body by an enzymatic reaction between adenosine-triphosphate (ATP) and methionine. It was discovered in 1952 in Italy and has been researched and manufactured there. SAMe works closely with folic acid and vitamin B-12 and functions as a methyl donor. This nutrient carries and donates methyl molecules necessary to facilitate the manufacture of DNA and brain neurotransmitters. Tissue levels of SAMe are typically low in the elderly.