top of page

B12- Mechanism of Action, Indications, uses, Administration, Side Effects

  • Vitamin B12, also known as cobalamin, is a water-soluble vitamin that plays a crucial role in various bodily functions.

  • It is involved in the synthesis of DNA, red blood cell production, nerve function, and the metabolism of fats and carbohydrates.

  • Here's a detailed explanation of B12, including its chemical formula, mechanism of action, indications, uses, administration, and side effects.

Chemical Formula

The chemical formula of vitamin B12 is C63H88CoN14O14P. It contains a complex structure consisting of a central cobalt atom surrounded by a corrin ring, a nucleotide loop, and various side chains.

Mechanism of Action:

Vitamin B12 has a unique mechanism of action. It acts as a cofactor for enzymes involved in two important reactions:

  1. Methionine synthase: Vitamin B12 is required for the conversion of homocysteine to methionine. This reaction is essential for the synthesis of DNA, RNA, and proteins. Methionine is also involved in various methylation reactions, which are crucial for gene expression and other cellular processes.

  2. Methylmalonyl-CoA mutase: Another enzyme dependent on vitamin B12 is methylmalonyl-CoA mutase. This enzyme is involved in the breakdown of certain amino acids and fatty acids. Without functional vitamin B12, methylmalonyl-CoA cannot be converted, leading to the accumulation of toxic compounds.

Indications and Uses:

Vitamin B12 is primarily used for the treatment and prevention of vitamin B12 deficiency. It is also used in various medical conditions where a deficiency is suspected or confirmed. Indications and uses of vitamin B12 include:

  1. Pernicious anemia: This is a type of anemia caused by impaired absorption of vitamin B12 due to the lack of intrinsic factor, a protein required for its absorption. Vitamin B12 injections or high-dose oral supplements are commonly used to treat this condition.

  2. Vitamin B12 deficiency: Deficiency can occur due to inadequate dietary intake, malabsorption disorders (e.g., celiac disease, Crohn's disease), gastrointestinal surgeries, or long-term use of certain medications (e.g., proton pump inhibitors, metformin). Vitamin B12 supplements are used to restore and maintain adequate levels.

  3. Vegan or vegetarian diets: Since vitamin B12 is primarily found in animal-based foods, individuals following strict vegan or vegetarian diets may be at risk of deficiency. B12 supplements or fortified foods are often recommended in these cases.

  4. Neurological disorders: Vitamin B12 deficiency can lead to neurological complications, such as peripheral neuropathy, cognitive decline, and mood disorders. Supplementation may be prescribed to manage or prevent these conditions.


Vitamin B12 can be administered through various routes, including:

  1. Oral: It is available as oral tablets, capsules, or liquid formulations. Oral supplements are typically used for maintenance therapy or mild deficiencies.

  2. Intramuscular (IM) injections: In severe deficiencies, or when oral absorption is impaired, vitamin B12 is often administered via IM injections. These injections are usually given monthly or as prescribed by a healthcare professional.

  3. Nasal gel: A nasal gel formulation of vitamin B12 is available, which is absorbed through the nasal mucosa. It is a convenient option for individuals who have difficulty with oral supplementation or injections.

Side Effects:

Vitamin B12 is generally considered safe when used in recommended doses. However, some individuals may experience certain side effects, although they are uncommon. These side effects may include:

  1. Allergic reactions: Rarely, individuals may develop allergic reactions such as itching, rash, or swelling after receiving vitamin B12 injections or supplements. Seek medical attention if any allergic symptoms


Related Posts

See All

Thanks for subscribing!

bottom of page