Taking 1,800 mg of oral alpha-lipoic acid daily for 19 days helped reduce nerve pain for type 2 patients, according to a Berlin study reported in the December 1999 issue of Diabetic Medicine. At the start of the trial, the patients all had multiple neuropathic symptoms such as burning and numbness. The double-blind, randomized, placebo-controlled trial was funded by German drug company ASTA Medica AG, which supplied the alpha-lipoic acid for the research.
There were 12 people each in the placebo and the alpha-lipoic acid groups, ranging in age from 18 to 70. Apart from various tests, which included HbA1c, cholesterol and triglycerides, performed at the start and end of the trial, patients were also asked about the intensity and symptoms of their nerve pain on a weekly basis.
By the end of the trial, those who had received alpha-lipoic acid reported a 47 percent reduction in neuropathic symptoms, compared to a 24 percent reduction for the placebo group. Intensity of pain dropped by 60 percent for the control group but only by 29 percent for the placebo group. The control group also reported a significant decrease in the disabling effects of their neuropathy. While the placebo group reported an increase in their levels of neuropathic disability. No significant adverse reactions were reported from using alpha-lipoic acid.
Although the researchers were not sure why alpha lipoic acid was able to reduce nerve pain in such a short period of time, they theorized that the reduction of free radical-mediated oxidative stress improves blood flow around the nerves.