What Does a B12 Shot Do for You?

Medically Reviewed on 9/3/2021
what does a B12 shot do for you
Vitamin B12 shots are given to prevent or treat disorders or health complications caused by vitamin B12 deficiency

Vitamin B12 shots are given to prevent or treat vitamin B12 deficiency. 

Vitamin B12, also called cyanocobalamin or hydroxocobalamin, is a vital nutrient that helps make DNA and hemoglobin. It keeps your nerves and brain healthy and plays an important role in improving concentration and preventing age-related memory loss. Vitamin B12 shot may be prescribed to prevent or treat the following:

  • Pernicious anemia (a condition in which there are low red blood cell counts due to an abnormality in B12 absorption by the intestines)
  • Megaloblastic anemia (a type of anemia in which there are very large red blood cells called megaloblasts)
  • Cognitive disorders, such as dementia (a disorder characterized by problems with memory, problem-solving abilities, language, etc.)
  • Disorders that affect B12 absorption, such as pancreatic diseases, intestinal infections, Crohn’s disease, and tropical sprue
  • Cardiovascular disease risk (by lowering blood homocysteine levels, which is a compound associated with an increased risk of heart problems)
  • Multiple sclerosis symptoms
  • Bell’s palsy recovery
  • B12 deficiencies related to:
    • Weight loss
    • Vegan or restrictive diets
    • Surgery to remove the part of the stomach or the ileum (the last part of the small intestine) 
    • Energy and endurance

What are signs of vitamin B12 deficiency?

Signs and symptoms of vitamin B12 deficiency signs may include:

What are the side effects of a B12 shot?

Vitamin B12 injections are generally safe. If side effects do occur, they are generally mild and may include:

Serious side effects are rare and may include:

If you experience serious side effects, contact your doctor right away.


Next to red peppers, you can get the most vitamin C from ________________. See Answer

What precautions should you take with vitamin B12 shots?

While taking vitamin B12 shots as energy boosters at health spas has become a rising trend, it’s important to exercise caution. Vitamin B12 shots should be taken only in prescribed doses and administered by a licensed medical practitioner.

Before taking a B12 shot, tell your doctor if you:

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Medically Reviewed on 9/3/2021
Harvard Health Publishing. Ask the Doctor: B12 Shots vs. Pills. https://www.health.harvard.edu/staying-healthy/ask-the-doctor-b12-shots-vs-pills

RxList. Cyanocobalamin. https://www.rxlist.com/cyanocobalamin-side-effects-drug-center.htm