Alpha lipoic acid, or ALA (also known as thioctic acid) is an antioxidant fatty acid produced naturally in the body and found in foods such as red meat, liver, brewer's yeast and green plants. ALA supplements use the synthetic form dl-alpha lipoic acid. Research shows that ALA also helps regenerate other antioxidants including vitamin C, vitamin E, and glutathione.
Although ALA is not considered to be essential in the diet because it can be manufactured in the body, some scientists recommend supplementing 20 to 50 mg per day to boost antioxidant levels. ALA has an excellent safety record, with no serious side-effects reported in over 30 years of clinical research. Although studies on diabetic patients have used as much as 1,800 mg of ALA per day, there is little evidence of additional benefit in doses greater than 600 mg per day.