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

Eating squid and octopus can also help boost your levels of vitamin A and vitamin B12. — Mark Gurarie, Health, 25 June 2026

People with higher homocysteine levels also tended to have lower vitamin B12 and folate. — Lindsay Curtis, Verywell Health, 23 June 2026

For instance, Susie explains that a 3.5-ounce serving (about 6 to 8 medium oysters) delivers more than 500 percent of the daily value for zinc and over six times the daily value for vitamin B12. — Bridget Shirvell, Martha Stewart, 9 June 2026

Nutritional deficiencies: Iron, ferritin, vitamin B12, folate, and vitamin D levels indicate whether dietary or absorption problems are causing symptoms such as fatigue, bone pain, or cognitive changes. — Web Golinkin, Forbes.com, 6 May 2026

That said, there’s no scientific evidence that taking a vitamin B12 supplement, or even eating more foods with vitamin B12, can stop hair loss from happening. — Rebecca Strong, USA Today, 3 Apr. 2026

The formula is gluten-free and features 24 essential vitamins and minerals, including vitamin B12, vitamin D and magnesium, to support your health. — Bestreviews, Mercury News, 28 Mar. 2026

It’s known that the body’s ability to absorb vitamin B12 decreases with age, and people 75 and older are at higher risk of deficiency. — Lindsey Leake, NBC news, 9 Mar. 2026

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