S-adenosylmethionine is quite a mouthful; the abbreviation SAMe (pronounced samm-ee) is easier to say. Its chemical structure and name are derived from two materials you may have heard about already: methionine, a sulfur-containing amino acid; and adenosine triphosphate (ATP), the body's main energy molecule.

SAMe was discovered in Italy in 1952. It was first investigated as a treatment for depression, but along the way it was accidentally noted to improve arthritis symptoms—a kind of positive side effect.

Unfortunately, SAMe is an extraordinarily expensive supplement at present. Full dosages can easily cost more than $200 per month.

The body makes all the SAMe it needs, so there is no dietary requirement. However, deficiencies in methionine, folate, or vitamin B12 can reduce SAMe levels. SAMe is not found in appreciable quantities in foods, so it must be taken as a supplement.

It's been suggested that the supplement trimethylglycine (TMG) might indirectly increase SAMe levels and provide similar benefits, but this effect has not been proven.