Alpha-lipoic acid (also known as Thioctic acid) is a physiological cofactor containing sulphur and involved in several relevant processes, particularly related to mytochondrial reactions aimed to energy production (decaboxylation of pyruvate  and of other alpha-ketoacids).

Moreover it works as an antioxidant molecule, scavenging free radicals, supporting regeneration of other molecules like  glutathion and vitamin C and thus benefitting many districts of the organism, particularly joints and cardiovascular system.