A naturally occurring micronutrient, synthesized in small amounts by plants and animals (including humans), with antioxidant and potential chemopreventive activities. Alpha-lipoic acid acts as a free radical scavenger and assists in repairing oxidative damage and regenerates endogenous antioxidants, including vitamins C and E and glutathione. This agent also promotes glutathione synthesis. In addition, alpha-lipoic acid exerts metal chelating capacities and functions as a cofactor in various mitochondrial enzyme complexes involved in the decarboxylation of alpha-keto acids. OR A substance that is being studied for its ability to protect normal cells from the side effects of chemotherapy and prevent peripheral neuropathy (numbness, tingling, burning, and weakness in the hands or feet). Alpha-lipoic acid is made by the body and can be found in foods such as organ meats, spinach, broccoli, peas, brussel sprouts, and rice bran. It can also be made in the laboratory. Alpha-lipoic acid is a type of antioxidant and chemoprotective agent.