Vitamin B6 deficiency is common in people with carpal tunnel syndrome, supplementing with the vitamin has reportedly relieved symptoms.
Some, but not all, studies have found vitamin B6 deficiency to be common in people with CTS. Supplementation with vitamin B6 has reportedly relieved the symptoms of CTS, but some researchers have not found this treatment to be beneficial.
Several studies report that people with CTS are helped when given 100 mg of vitamin B6 three times per day. Although some researchers have found benefits with lesser amounts, using less than 100 mg taken three times per day for several months has often failed. Most doctors assume that people with CTS who respond to vitamin B6 supplementation do so because of an underlying deficiency. However, at least one group of researchers has found vitamin B6 to “dramatically” reduce pain in people with CTS who did not appear to be B6-deficient. Some doctors believe that B6 is therapeutic because it reduces swelling around the carpal tunnel in the wrist; this theory remains completely undocumented.
Very high levels of vitamin B6 can damage sensory nerves, leading to numbness in the hands and feet as well as difficulty in walking; supplementation should be stopped if these symptoms develop after beginning vitamin B6 supplementation. Vitamin B6 is usually safe in amounts of 200 to 500 mg per day, although occasional problems have been reported in this range. Higher amounts are clearly toxic. Any adult taking more than 200 mg of vitamin B6 per day for more than a few months should consult a doctor.
In order to be effective, vitamin B6 must be transformed in the body to pyridoxal-5’-phosphate (PLP). Some doctors have suggested that people who do not respond well to vitamin B6 supplements should try 50 mg of PLP three times per day. There is no clear evidence that using PLP provides any advantage in reducing symptoms of CTS.