Carpal Tunnel Syndrome and Vitamin B6

More than 25 years ago, researchers noted that people with carpal tunnel syndrome seemed to be deficient in vitamin B6.² This led to widespread use of B6 as a treatment for carpal tunnel. However, a recent study found no association between CTS and B6 -deficiency.³ In any case, even if B6 -deficiency were common in CTS, that by itself wouldn't prove that taking B6 supplements can reduce carpal tunnel syndrome symptoms.

Since vitamin B6 has not been proven effective and may be harmful in high doses, it should be taken with caution for carpal tunnel syndrome.

Read more details about Vitamin B6.

A few studies have investigated the effectiveness of vitamin B6 specifically for carpal tunnel syndrome. Most were poorly designed and involved few people. The two (albeit small) randomized, double-blind, placebo-controlled studies that do exist found no evidence that vitamin B 6 effectively treats carpal tunnel.

The first study, which enrolled only 15 people, found no significant difference after 10 weeks among those taking vitamin B6, placebo, or nothing at all.⁴

The second, involving 32 people, did find some benefits, but these were fairly minor.⁵ There was no improvement in nighttime pain, numbness, or tingling, nor in objective measurements of median nerve function. Some benefit, however, was seen in the relatively less important symptoms of finger swelling and discomfort after repetitive motion.

Again, the thought that vitamin B6 might be helpful to take for carpal tunnel syndrome is based on the fact that some people with with this health challenge were found to be deficient in the vitamin. However, this does not mean that supplementing the vitamin will actually help treat the condition.

Safety Issues

The safe upper levels for daily intake of vitamin B 6 ¹ are as follows:

• Children
• 1-3 years: 30 mg
• 4-8 years: 40 mg
• Males and Females
• 9-13 years: 60 mg
• 14-18 years: 80 mg
• 19 years and older: 100 mg
• Pregnant or Nursing Women
• 18 years old and younger: 80 mg
• 19 years and older: 100 mg

At higher dosages (especially above 2 g daily) there is a very real risk of nerve damage. Nerve-related symptoms have even been reported at doses as low as 200 mg.² (This is a bit ironic, given that B6 deficiency also causes nerve problems.) In some cases, very high doses of vitamin B6 can cause or worsen acne symptoms.⁴

In addition, doses of vitamin B6 over 5 mg may interfere with the effects of the drug levodopa when it is taken alone.^{6, 7} However, vitamin B6 does not impair the effectiveness of drugs containing levodopa and carbidopa.

Maximum safe dosages for individuals with severe liver or kidney disease have not been established.

Interactions You Should Know About

If you are taking:

• Isoniazid (INH) , penicillamine , hydralazine , theophylline , or MAO inhibitors : You may need extra vitamin B 6 , but take only nutritional doses. Higher doses of B 6 might interfere with the action of the drug.

• Levodopa without carbidopa (for Parkinson's disease): Do not take more than 5 mg of vitamin B 6 daily, except on medical advice.

• Antipsychotic medications: B 6 might reduce side effects.

1. Dietary Reference Intakes for Thiamin, Riboflavin, Niacin, Vitamin B6, Folate, Vitamin B12, Pantothenic Acid, Biotin, and Choline (1998). Available at www.nap.edu. Accessed October 4, 2001.

1. Stransky M, Rubin A, Lava NS, et al. Treatment of carpal tunnel syndrome with vitamin B6: a double-blind study. South Med J. 1989;81:841-842.

2. Ellis JM, Kishi T, Azuma J, et al. Vitamin B6 deficiency in patients with a clinical syndrome including the carpal tunnel defect. Biochemical and clinical response to therapy with pyridoxine. Res Commun Chem Pathol Pharmacol. 1976;13:743-757.

3. Franzblau A, Rock CL, Werner RA, et al. The relationship of vitamin B6 status to median nerve function and carpal tunnel syndrome among active industrial workers. J Occup Environ Med. 1996;38:485-491.

4. Stransky M, Rubin A, Lava NS, et al. Treatment of carpal tunnel syndrome with vitamin B6: a double-blind study. South Med J. 1989;81:841-842.

5. Spooner GR, Desai HB, Angel JF, et al. Using pyridoxine to treat carpal tunnel syndrome . Can Fam Physician . 1993;39:2122-2127.

6. Garfinkel MS, Singhal A, Katz WA, et al. Yoga-based intervention for carpal tunnel syndrome: a randomized trial. JAMA. 1998;280:1601-1603.

7. Carter R, Hall T, Aspy CB, et al. Effectiveness of magnet therapy for treatment of writs pain attributed to carpal tunnel syndrome. J Fam Pract. 2002;51:38-40.