Clinical Trial of Methylcobalamin

I’m taking another break from vitamin K2 to report on a study that a reader passed on regarding methylcobalamin (1).

There has been very little testing of methylcobalamin and so I normally recommend taking cyanocobalamin because it is a more stable form of vitamin B12 and there are anecdotal reports of people needing large doses of methylcobalamin to achieve results.

A 2011 clinical trial from Korea sheds some light on this issue. The study was done with people who had their stomachs removed (gastrectomy) due to cancer. Patients who have had a gastrectomy can no longer produce intrinsic factor, a molecule required for efficient B12 absorption, and they are typically given B12 injections.

In this trial, patients took 1,500 µg of methylcobalamin each day.

At baseline, their B12 levels were an average of 170 pg/ml and 24 out of 30 had tingling in their hands and feet, the traditional sign of vitamin B12 deficiency. Many had other indicators as well, including elevated homocysteine (an average of 17.5 µg/l). Over the course of the 3 month trial, vitamin B12 levels steadily increased to an average of 810 pg/ml, homocysteine steadily decreased to 11.4 µg/l, 28 patients experienced symptom relief, and 16 patients were free of all symptoms.

A drawback to this trial is that it did not have a placebo group; all the patients knew they were receiving vitamin B12. But these results are, in my opinion, too impressive to be due simply to placebo and based on the homocysteine and symptom improvement, it appears safe to say that 1,500 µg per day of methylcobalamin should be enough for just about anyone.

I have added a paragraph about this study to the Methylcobalamin & Adenosylcobalamin page at


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1. Kim HI, Hyung WJ, Song KJ, Choi SH, Kim CB, Noh SH. Oral vitamin B12 replacement: an effective treatment for vitamin B12 deficiency after total gastrectomy in gastric cancer patients. Ann Surg Oncol. 2011 Dec;18(13):3711-7. | link

One Response to “Clinical Trial of Methylcobalamin”

  1. Dan Says:

    What is amazing to me is that you can remove 95%+ of someone’s stomach and still achieve physiological levels of B12 in the human body using the oral route. I guess the less efficient downstream site of absorption becomes the major prevailing mechanism, if you give very large oral amounts. I have a semi-vegan patient (not gastrectomized) with documented B12 deficiency which has not responded to sublingual B12 drops. Her naturopath recommended that she start injections but she does not know the dose of what was in those drops. I told her to consider increasing her oral dose to a much higher, prescribed level AND combine these with shots her naturopath recommended (though of course, just doing shots alone should be adequate, but at least this way, she has a back-up route of protection if she misses a shot).

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