Alpha lipoic acid (ALA), also known as lipoic acid (LA) or thioctic acid, is a vitamin-like antioxidant. Some refer to ALA as the "universal antioxidant" because it has the unique attribute of being both fat and water-soluble. Another unique aspect of ALA is its ability to regenerate other antioxidants back to active states, including vitamin C, vitamin E, glutathione, and coenzyme Q10.

Several experimental and clinical studies have shown potential therapeutic uses for alpha lipoic acid in addressing diabetes, atherosclerosis, cataracts, heavy metal poisoning, neurodegenerative diseases, and HIV infection.

Alpha lipoic acid is produced naturally by most organisms, including humans. It is also present in many foods, with above-average amounts in organ meats (kidney, heart, liver), potatoes, spinach, and broccoli.  Unfortunately, total dietary availability of ALA is quite poor. One of the first groups of researchers to isolate alpha-lipoic acid required nearly 10 tons of liver residue to produce a mere 30mg of crystalline LA. Because of this, all supplemental ALA is produced synthetically.

Currently no RDI value has been set, nor has the issue been adequately studied. Some researchers believe that the amount needed for therapeutic antioxidant activity exceeds that produced by our bodies or consumed in a normal diet. As such, alpha lipoic acid is a strong candidate for dietary supplementation. Maintenance doses of 10-25 mg per day have been suggested, while doses up to several hundred milligrams per day have been used therapeutically.