ALA, also known as thioctic acid or 6,8-dithiooctanoic acid, is essential for cell function but not essential in the nutritional sense because our bodies make it. Older skin may be "starved" of this very important antioxidant and cofactor. Lipoic acid, a naturally occurring dithiol complex, is the prosthetic (i.e. non-proteic) group of several enzymes, including the transacetylase part of the enzyme complex that catalyzes the decarboxylation of pyruvate so that the remaining 2-carbon group can enter the Krebs cycle. Aside from its fundamental role in enzyme function, in vitro and in vivo studies suggest that ALA also acts as a powerful micronutrient with diverse pharmacological and antioxidant properties.