Thioctic Acid Best Antioxidant Anti-Ageing Thioctic Acid description Thioctic acid is the technical name for the antioxidant alpha lipoic acid. Unlike many antioxidants that are either water-soluble or oil-soluble, thioctic acid is both. Despite claims to the contrary, alpha lipoic acid isn’t the best antioxidant around. It is one of many that are beneficial for skin.