Alpha lipoic acid is a sulphur-containing fatty acid present in every cell in the human body. It has many important biological functions and characteristics that have made it a popular nutritional supplement in recent years.
Alpha lipoic acid (ALA) is a cofactor in aerobic metabolism and is therefore required by the body for the production of energy by the Kreb's cycle within the mitochondria found in virtually all cells (red blood cells being an exception).
Much of the popularity of ALA as a nutritional supplement stems from its reported antioxidant properties. Antioxidants are required to neutralise highly reactive chemicals called 'free radicals' which can be harmful to the body. ALA is unique in that it can function in both water and fat, unlike well known antioxidants such as vitamin C (only water-soluble) and vitamin E (only fat soluble). This unique ability has led to ALA being given the nickname of the 'Universal Antioxidant'. ALA is able to regenerate other important antioxidants within the body, vitamins C and E and glutathione when they have done their job of neutralising free radicals by allowing themselves to become oxidised. ALA is also thought to act as an antioxidant itself but research is conflicting.
ALA may also be of interest to those suffering from environmental illnesses since as it contains sulphur it acts as quite a potent chelating agent. Chelating agents are used to bind to toxic metals in the body, removing them from tissues and facilitating their removal from the body. ALA in oral supplement form is now frequently used in chelation therapy and is one of only very few agents approved for this purpose by the US Food and Drug Administration (FDA). Unlike other common chelating agents like DMSA and DMPS, ALA is able to pass through the blood-brain barrier and chelate toxic metals such as mercury that have been deposited in the brain where they can cause significant neurotoxicity and symptoms of disease. In animal experiments ALA has also been shown to significantly increase excretion of inorganic mercury in bile (much of which then passes out of the body with bowel movements).
Finally, ALA has been shown in some experiments to increase the uptake of glucose by cells making it potentially useful for conditions involving sugar metabolism dysregulation such as diabetes and metabolic syndrome. These findings have yet to be confirmed however.