vitamin B₁₂

noun

-ˈbē-ˈtwelv 

1

: a complex cobalt-containing compound C₆₃H₈₈CoN₁₄O₁₄P that occurs especially in liver, is essential to normal blood formation, neural function, and growth, and is used especially in treating pernicious and related anemias and in animal feed as a growth factor

called also cyanocobalamin

2

: any of several compounds similar to vitamin B₁₂ in action but having different chemistry

Examples of vitamin B₁₂ in a Sentence

Recent Examples on the Web

This usually requires vegans to eat fortified foods or take a variety of supplements, especially for nutrients like vitamin B12, which is only found in animal products. —Daryl Austin, USA TODAY, 11 Feb. 2025

The new study found a higher prevalence of micronutrient deficiencies, especially vitamin B12, in people who took metformin. —Kaitlin Sullivan, Health, 6 Feb. 2025

Some vitamins and minerals may be particularly helpful in managing symptoms, including iodine, selenium, vitamin B12, vitamin D, and antioxidants. —Merve Ceylan, Health, 25 Jan. 2025

Boosting older adults’ health: Aging can affect the absorption of certain nutrients, such as vitamin B12. —Lindsay Curtis, Verywell Health, 22 Jan. 2025

According to the doctor, stress can definitely be a culprit—but gray hair actually comes down to genetics as well as certain diseases like vitiligo, vitamin B12 deficiency, alopecia areata. —Laura Solla, Vogue, 1 Jan. 2025

Where is Sura Ali now? Praised for her quiet confidence, Sura Ali brought her A-game to every challenge on Rhythm + Flow — despite also battling health issues from a vitamin B12 deficiency. —Emily Blackwood, People.com, 5 Dec. 2024

Several blood tests can help identify vitamin B12 deficiency:3 Vitamin B12 level: While this blood test not a common screening tool unless a deficiency is suspected, a serum vitamin B12 level can diagnose a B12 deficiency. —Sohaib Imtiaz, Verywell Health, 11 Jan. 2025

These blood tests might include a complete blood count; a metabolic panel; and tests for fasting blood glucose, thyroid stimulating hormone, and vitamin B12 levels. —Ruth Jessen Hickman, Md, Health, 23 Dec. 2024

Word History

First Known Use

1948, in the meaning defined at sense 1

Kids Definition

vitamin B₁₂

noun

-ˈbē-ˈtwelv

: a member of the vitamin B complex that contains cobalt, occurs especially in liver, and is needed for normal blood formation, nerve function, and growth

also : any of several other compounds with similar activity

Medical Definition

vitamin B₁₂

noun

-ˈbē-ˈtwelv 

1

: a complex cobalt-containing compound C₆₃H₈₈CoN₁₄O₁₄P found in animal products (as meat and eggs) that is essential to normal blood formation, neural function, and growth and is used especially in treating pernicious and related anemias and in animal feed as a growth factor

called also cyanocobalamin

2

: any of several compounds similar to vitamin B₁₂ in action but having different chemistry