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

Other diseases that cause similar symptoms and findings include lupus, Lyme disease, fibromyalgia, vitamin B12 deficiency, and less common conditions like neuromyelitis optica and MOG antibody disease. — Lindsay Karp, STAT, 23 Oct. 2026

The food is also a decent source of nutrients, such as phosphorus, vitamin B12, selenium and zinc, which support blood cell formation, nerve function, bone health and metabolism. — Kristen Rogers, CNN Money, 22 Oct. 2026

Aside from vitamin B12, organ meats like kidneys are nutrient-dense, providing substantial amounts of essential amino acids, iron, selenium, zinc, copper, phosphorus, and omega-3 fatty acids. — Joy Emeh, HEALTH, 19 Oct. 2026

Additionally, iron and B vitamins such as folate (vitamin B9) and cyanocobalamin (vitamin B12) work together to support healthy red blood cell production. — Sara Hoffman, Verywell Health, 16 Oct. 2026

Advertisement Kinkade’s vial of tirzepatide, for instance, included the vitamin B12. — Alana Semuels, Time, 7 Oct. 2026

Iron, ferritin, vitamin B12, vitamin D, and zinc all play an important role, along with adequate protein and complex carbohydrates to fuel your follicles. — Maggie Ryan, Flow Space, 25 Aug. 2026

Oral Supplements Doctors may prescribe iron supplements to increase iron levels in the body or vitamin B12 supplements to treat vitamin B12–deficiency anemia. — Emily Kay Votruba, EverydayHealth.com, 19 Aug. 2026

The arbitrator, a retired judge, sided with Kaiser’s doctors and experts, who questioned whether Fowler’s problems were caused by a deficiency of vitamin B12. — Melody Petersen, Los Angeles Times, 20 July 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