Alpha-lipoic acid is a vitamin-like substance that is often described as "nature's perfect antioxidant". First of all, alpha-lipoic acid is a very small molecule that is efficiently absorbed and easily crosses cell membranes. Unlike vitamin E, which is primarily fat-soluble, and vitamin C, which is water-soluble, alpha-lipoic acid can quench either water- or fat-soluble free radicals both inside the cell and outside the intracellular spaces. Furthermore, alpha-lipoic acid extends the biochemical life of vitamin C and E as well as other antioxidants.
Alpha-lipoic acid is an approved drug in Germany for the treatment of diabetic neuropathy. In fact, it has been successfully used in Germany for more than 30 years. The beneficial effects of alpha-lipoic acid in diabetic neuropathy have been confirmed in several double-blind studies at a dosage of 300 to 600 mg daily.1,2 Although alpha-lipoic acid's primary effect in improving neuropathy is thought to be the result of its antioxidant effects, it has also been shown to lead to an improvement in blood sugar metabolism, improve blood flow to peripheral nerves, and actually stimulate the regeneration of nerve fibers. Its ability to improve blood sugar metabolism is a result of its effects on glucose metabolism and an ability to increase insulin sensitivity. Its importance in treating diabetic neuropathy cannot be overstated.