The November, 2006 issue of the journal Diabetes Care published a report concerning the finding that alpha-lipoic acid given to diabetic patients improved symptomatic diabetic polyneuropathy, a painful condition of the nerves that affects the quality of life of many diabetics. Alpha-lipoic acid is an antioxidant that has been previously shown to help improve the symptoms of diabetic neuropathy when administered intravenously for three weeks.
In a multicenter, randomized, double-blind trial known as SYDNEY 2, 181 diabetics in Russia and Israel with symptoms of distal symmetric polyneuropathy received a placebo for one week followed by a daily oral supplement of 600 milligrams, 1,200 milligrams, or 1,800 milligrams alpha-lipoic acid, or a placebo for five weeks. Participants scored their symptoms during screening, before beginning treatment, and after each week of treatment.
One hundred sixty-six subjects completed the trial. There was a significant reduction in mean total symptom scores (TSS) and individual scores for stabbing pain and burning pain compared to the placebo group. Total symptom scores at the end of the trial for those who received alpha-lipoic acid were not significantly different, with 62 percent of the subjects who received 600 milligrams alpha-lipoic acid experiencing a 50 percent or greater reduction in total symptom scores after five weeks, compared to 50 percent of those who received 1,200 milligrams and 56 percent of those who received 1,800 milligrams. None of the patients who received the 600 milligram dose dropped out of the study, whereas 11 of those who received the higher doses discontinued the study due to nausea, making the 600 milligram dose appear to be the best choice.
Alpha-lipoic acid’s ability to improve neuropathy symptoms may be due to an improvement in blood flow caused by alpha-lipoic acid’s antioxidant action. The authors conclude that the benefit of orally administered alpha-lipoic acid in the current trial is comparable to that found for the compound when administered intravenously, and note that significant improvement is demonstrable within one to two weeks of treatment.