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Vitamin B₁₂

Cobalamin (Vitamin B12) is a water-soluble essential vitamin that is known to play roles in neurology.

Our evidence-based analysis on vitamin b₁₂ features 70 unique references to scientific papers.

Research analysis led by and reviewed by the Examine team.
Last Updated:

How to Take

Recommended dosage, active amounts, other details

2.4 mcgs per day is the RDA for adults, generally (more is needed in some circumstances such as pregnancy). 100 mcg seems top be sufficient to reduce homocysteine for those with deficiency. Supplementation of vitamin B12 tends to be around 1,000 mcg (1 mg) of supplemental vitamin B12 to persons who are at risk for B12 insufficient or deficiency, mostly older individuals and vegans, though this dose is best only used for short periods with monitoring of levels so as to avoid excessive dosing and the potential risks.

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Human Effect Matrix

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The Human Effect Matrix summarizes human studies to tell you what effects Vitamin B₁₂ has on your body, how much evidence there is, and how strong these effects are.

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Grade Level of Evidence
Robust research conducted with repeated double-blind clinical trials
Multiple studies where at least two are double-blind and placebo controlled
Single double-blind study or multiple cohort studies
Uncontrolled or observational studies only
Level of Evidence
? The amount of high quality evidence. The more evidence, the more we can trust the results.
Outcome Magnitude of effect
? The direction and size of the supplement's impact on each outcome. Some supplements can have an increasing effect, others have a decreasing effect, and others have no effect.
Consistency of research results
? Scientific research does not always agree. HIGH or VERY HIGH means that most of the scientific research agrees.
Notes
grade-c - - See study
grade-d Minor - See study
A slight improvement in verbal learning associated with 1,000mcg of B12 supplementation in persons with lacunar stroke, according to at least one pilot study
grade-d - - See study
grade-d - - See study

Studies Excluded from Consideration

  • Confounded with other B-vitamins[1]

  • Used intramuscular injections[2]

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Things to Note

Primary Function:

Also Known As

Cyanocobalamin, cobalamin, methylcobalamin, 5-deoxyadenosylcobalamin, adenosylcobalamin, cobamamide, dibencozide, hydroxocobalamin

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Click here to see all 70 references.