What is the second name of B12?

November 17, 2025 •

3 min read

According to the NIH, approximately 3.6% of adults have a vitamin B12 deficiency, with the risk increasing for those over 60. A common point of confusion is what is the second name of B12, which is actually cobalamin, a term that encompasses several different forms of this essential nutrient.

Quick Summary

The second name for B12 is cobalamin, an essential water-soluble vitamin. It is critical for the health of your nerve and blood cells, DNA synthesis, and metabolism.

Key Points

Cobalamin is the scientific name: The second name for Vitamin B12 is cobalamin, which is a collective term for a group of compounds with B12 activity.
Forms of B12 differ: There are natural active forms like methylcobalamin and adenosylcobalamin, and synthetic forms like cyanocobalamin, commonly used in supplements.
Crucial for nerve health: Vitamin B12 is essential for maintaining the nervous system and the myelin sheath that protects nerves.
Vital for red blood cells: It plays a key role in the formation of red blood cells, and a deficiency can lead to anemia.
Deficiency has varied causes: Poor diet (especially vegan), pernicious anemia, digestive disorders, and certain medications are common causes of low B12 levels.
Symptoms can take years to appear: The body stores a large amount of B12, so a deficiency can progress for years before symptoms like fatigue, numbness, and memory issues become noticeable.
Animal products are the primary source: B12 is naturally found in meat, dairy, eggs, and seafood; fortified foods are a reliable source for vegans.

The Scientific Name for B12: Cobalamin

Vitamin B12 is scientifically known as cobalamin, a name derived from the mineral cobalt it contains. Cobalamin is an umbrella term for compounds with vitamin B12 activity, existing in active, natural co-enzyme forms and synthetic versions requiring bodily conversion.

The Four Primary Forms of Cobalamin

Understanding the various forms is beneficial as they are found in different sources and supplements:

Methylcobalamin: A natural, active co-enzyme B12 found in foods and some supplements.
Adenosylcobalamin: Another natural co-enzyme B12 working alongside methylcobalamin for bodily functions.
Hydroxycobalamin: A highly bioavailable, natural B12 produced by bacteria, used for severe deficiencies and convertible to active forms.
Cyanocobalamin: A synthetic form in supplements and fortified foods, converted to active forms by the body. It is known for stability and cost-effectiveness.

The Critical Functions of Vitamin B12

Vitamin B12 is vital for numerous biological processes, including:

Red Blood Cell Formation: Essential for healthy red blood cells; deficiency can cause megaloblastic anemia.
Nervous System Health: Crucial for the development and function of the central nervous system, maintaining the myelin sheath. Deficiency can lead to nerve damage symptoms.
DNA Synthesis: A key factor, especially for rapidly dividing cells.
Energy Metabolism: Involved in converting food to energy, explaining fatigue as a deficiency symptom.

Causes and Symptoms of B12 Deficiency

B12 deficiency can stem from diet, absorption issues, or medical conditions. Due to large body stores, symptoms may appear years later.

Common Causes

Dietary: High risk for vegans and strict vegetarians as B12 is primarily in animal products.
Pernicious Anemia: An autoimmune disease impairing intrinsic factor production needed for B12 absorption.
Gastrointestinal Issues: Conditions like Crohn's, celiac disease, gastritis, or gastric surgery can hinder absorption.
Age: Adults over 60 are more prone due to reduced stomach acid.
Medications: Some drugs, like metformin and proton pump inhibitors, can affect B12 levels long-term.

Notable Symptoms

A B12 deficiency can manifest in several ways. Common symptoms include fatigue, a sore or red tongue, tingling sensations, and neurological changes such as memory loss or confusion. Physical signs might also include pale or jaundiced skin, heart palpitations, or shortness of breath.

Comparison of B12 Supplement Forms


Feature	Cyanocobalamin	Methylcobalamin	Hydroxocobalamin
Source	Synthetic	Naturally Occurring	Naturally Occurring
Availability	Widely used in oral supplements and fortified foods	Used in supplements (natural form)	Used for injections to treat severe deficiency
Cost	Generally more affordable	Can be more expensive	Only by prescription, often injected
Bioavailability	Good absorption, especially at lower doses	High bioavailability, especially in sublingual form	High bioavailability, especially via injection
Stability	Very stable, with a longer shelf life	Less stable than cyanocobalamin	Stable, also used for injections
Conversion	Must be converted by the body into active forms	Active form, no conversion needed	Converted into active forms

Food Sources and Supplementation

Dietary intake is the primary source for most, but supplementation is often needed for those with absorption issues or dietary restrictions.

Dietary Sources of B12

Excellent sources of B12 include meat, poultry, fish, and seafood. Dairy products and eggs also contain the vitamin. Many food products are fortified with B12, providing a crucial source for vegans and vegetarians.

Supplementation Options

Various supplements are available. It is recommended to consult a healthcare provider for guidance on the best option. Options include oral supplements (often high dose for poor absorption), sublingual supplements (designed for better absorption), injections (a standard treatment for severe deficiency, bypassing digestion), and a prescription nasal gel.

Conclusion

The second name of B12 is cobalamin, encompassing different forms of this vital nutrient. Cyanocobalamin is a common synthetic form in supplements, while methylcobalamin is a natural active form. Understanding these and B12's functions is key for recognizing deficiency risks, symptoms, and appropriate action via diet or supplementation. Adequate B12 intake supports overall health, particularly the nervous system and red blood cells. For more information, visit the National Institutes of Health.

Frequently Asked Questions

Yes, cobalamin is the scientific and collective name for vitamin B12 and all its various forms, including cyanocobalamin and methylcobalamin.

Methylcobalamin is a naturally occurring, active form of B12, while cyanocobalamin is a synthetic, more stable version often used in supplements. The body converts cyanocobalamin into active forms like methylcobalamin for use.

Since vitamin B12 is naturally found almost exclusively in animal products, people following vegan or strict vegetarian diets need to rely on fortified foods or supplements to ensure adequate intake.

Yes, a severe and prolonged B12 deficiency can damage the nerves and lead to neurological problems such as tingling, numbness, difficulty walking, and memory issues.

B12 absorption is a complex process involving stomach acid and a protein called intrinsic factor. Malabsorption can occur if either of these is lacking, leading to deficiency.

Groups at higher risk include older adults, people with digestive disorders like Crohn's disease, those who have had stomach surgery, and individuals on vegan diets.

B12 is a water-soluble vitamin and generally considered safe even at high supplemental doses, with no upper limit established due to lack of observed toxicity. However, consult a healthcare provider for proper dosage guidance.

Symptoms can include fatigue, weakness, a sore tongue, tingling in the hands and feet, memory loss, and difficulty with balance.