SAMe is a metabolite of methionine (an essential amino acid). It is a chiral molecule consisting of two forms: (S,S) SAMe and (R,S) SAMe. The biologically active form is the (S,S) structure, while the (R,S) structure is biologically inactive.
Jarrow Formulas SAMe is naturally produced through microbiological fermentation and then specially processed without chemical solvents to maintain 68-80% (S,S) SAMe, the highest available active level.