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Can you take too much Vitamin B12?

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Eggs are a good dietary source of vitamin B12.

Eggs are a good dietary source of vitamin B12.

Photo © Andre Schaer
Question: Can you take too much Vitamin B12?
Can you take too much Vitamin B12? I just bought my first bottle of sublingual B12 and it has 2500 mcg one time per day. My friend has 500 mcg sublingual B12 and takes it two times per day. What are the dangers or cautions that I need to be aware of if I take this vitamin on a daily basis?

Vicki - About.com User

Answer: Vitamin B12, or Cyanocobalamin, is important for energy use and metabolism. Overdoses are almost unknown, and although 2500 mcg is a high dose, it is safe to take daily.

Some things to consider with vitamin B12 supplements:

  • Take vitamin B12 and folic acid together. A deficiency of one can mask the other. They are usually sold together as one supplement.
  • Some people have trouble absorbing and using vitamin B12 because they don't make enough of a substance called intrinsic factor or hydrochloric acid in their stomachs. Vitamin B12 may be absorbed best by taking sublingual supplements that dissolve under the tongue.
  • A lack of intrinsic factor may lead to Pernicious Anemia.
  • Vegans may wish to supplement vitamin B12 since it is almost exclusively found in animal products.
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