vitamin B12

American  

noun

1. a deep-red crystalline, water-soluble solid, C 63 H 88 N 14 O 14 PCo, obtained from liver, milk, eggs, fish, oysters, and clams: a deficiency causes pernicious anemia and disorders of the nervous system.

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vitamin B12 British  

noun

1. another name for cyanocobalamin

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vitamin B12 Scientific  

1. A water-soluble, complex organic compound containing cobalt, found especially in meat, liver, eggs, milk, and milk products. Vitamin B ₁₂ is necessary for the synthesis of DNA by the body, for the production of blood cells, and for maintaining the health of nerves. A deficiency of vitamin B ₁₂ in the diet results in pernicious anemia.

2. Also called cobalamin cyanocobalamin

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Etymology

Origin of vitamin B12

First recorded in 1945–50

Compare meaning

How does vitamin-b12 compare to similar and commonly confused words? Explore the most common comparisons:

• vitamin B12 vs. B complex

Example Sentences

"This suggested relationship between vitamin B12, folate, and fatigue in healthy individuals may represent the first report of its kind," said Professor Kanouchi.

From Science Daily • May 29, 2026

"A lot of people were suffering from chronic fatigue, constant headaches, low vitamin B12, which was subsequently causing things like heart palpitations and very foggy heads," she said.

From BBC • May 18, 2026

However, they also had lower intakes of energy, protein, fat, vitamin B12, and zinc.

From Science Daily • Dec. 21, 2025

As the crops are rich in protein, carbohydrate, omega-3s, fatty-acids, and vitamin B12, Mr Haflidason believes growing microalgae this way, could help tackle global food insecurity.

From BBC • Jan. 20, 2025

We are, after all, a planet where the rain contains vitamin B12!

From "The Lives of a Cell" by Lewis Thomas