Alpha-lipoic acid is an antioxidant that is manufactured in the human body. Antioxidants are substances that work by attacking "free radicals," waste products created when the body turns food into energy. There are also many sources of free radicals in the environment such as ultraviolet rays, radiation, and toxic chemicals in cigarette smoke, car exhaust, and pesticides. Free radicals cause harmful chemical reactions that can damage cells in the body, making it harder for the body to fight off infections. As a result a person becomes more susceptible to long term diseases such as diabetes and liver damage. more info