There have been some studies that suggest that taking a vitamin B6 supplement can stop or reduce the symptoms of carpal tunnel syndrome, although this evidence is inconclusive.
Vitamin B6 is needed for a variety of functions. It helps with the formulation of red blood cells, the healthy functioning of the nervous system and immune system, correct metabolism, and the production of serotonin which helps guard against depression and other mental disorders. Pregnant women can sometimes alleviate morning sickness with vitamin B6.
Some research has shown vitamin B6 to be an effective treatment for carpal tunnel syndrome. For instance, a study in Spain showed that six patients had clinical improvement and increased nerve function after supplementation:
"Patients were treated with 150 mg of pyridoxine (B6) daily for three months. In six patients there were clinical and electrophysiological improvement and erythrocyte aspartate aminotransferase increased more than in the other six patients. The data obtained appear to indicate that although vitamin B6 deficiency is not common in carpal tunnel syndrome patients, pyridoxine supplementation can be recommended as adjuvant treatment in those patients undergoing surgery."
An older study found that not only did vitamin B6 resolve the symptoms of carpal tunnel syndrome, but it was apparent that in some cases, the syndrome was caused by a vitamin B6 deficiency.
"Clinical evaluation was made of cross-over treatments by pyridoxine and a placebo of patient 22 having the carpal tunnel syndrome. On placebo, both the vitamin B6 deficiency and syndrome reappeared. Retreatment with 100 mg again corrected both the deficiency and syndrome. Scores of 17 symptoms revealed reductions at both the 2- and 100-mg dosages. Conduction through the carpal tunnels had improved by electromyography. These and previous data on a total of 22 patients showed the concomitant presence of a deficiency of vitamin B6 and the carpal tunnel syndrome; a causal relationship is apparent."