Alpha-lipoic acid, the universal antioxidant, consists of two different forms, “R” and “S,” which have different properties. The “R” form is the biologically active component (native to the body) that is responsible for lipoic acid’s phenomenal antioxidant effect. The “S” form is not very biologically active. Alpha-lipoic acid supplements typically consist of the “R” and “S” forms in a 50/50 ratio. That means a 100 mg alpha-lipoic acid supplement is providing 50 mg of the biologically active “R” form.
