“Glutathione” — protects cells against various free radicals. Glutathione levels have been shown to decrease with age. Glutathione cannot be absorbed in the stomach, and therefore levels of this cellular protector cannot be increased with dietary supplementation. Instead, alternate antioxidants (i.e. alpha-lipoic acid) and precursors to glutathione (i.e. N-acetyl cysteine) must be taken in order to increase glutathione levels.