Benefits of B12 Shots: 5 Important Facts To Know

Vitamin B12 is an essential nutrient that is important for maintaining healthy nerve cells, DNA synthesis1, and red blood cell formation. A deficiency in vitamin B12 can lead to a variety of symptoms and health problems.

This article describes the uses and benefits of B12 shots in curing vitamin B12 deficiency in the body, which has various negative impacts on our health such as hair loss, anxiety, fatigue, etc., and the types of vitamin B12 used in these shots for different purposes.

1. Vitamin B12 And Its Importance In Our Body

Vitamin B12, also known as cobalamin, is water-soluble vitamin2 intricated in the metabolism of every cell in our body. Vitamin B12 plays a vital role in the human body to produce red blood cells for proper nerve tissue health and the functioning of the brain, DNA, and other functions.

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Photo by Louis Hansel on Unsplash

2. Symptoms of Vitamin B12 Deficiency

Vitamin B12 deficiency occurs due to inadequate absorption of these vitamins by people or inadequate consumption by the body. Rich vitamin B12 are milk, cheese, butter, eggs, meat, and poultry from other animal foods.

Strict vegetarians and people following a vegan diet are at higher risk of developing a deficiency of this vitamin if they don’t consume grains rich in vitamin B12. Less acid production in the stomach due to gastric bypass surgery3 also causes a lack of vitamin B12.

Crohn’s disease is an autoimmune disease that also causes vitamin B12 deficiency in our body. This inflammatory disease causes ulcerations throughout the GI tract in our body and especially affects the colon and small bowel. Uncontrolled inflammation can cause vitamin B12 deficiency.

Graves’ disease4 or lupus are immune system disorders that increase your risk of having vitamin B12 deficiency.

⚠️9 Vitamin B12 Deficiency WARNING Signs! [B12 Foods vs. B12 Shots?]

2.1. Various Vitamin B12 Deficiency Symptoms Are:

  • Balance problems
  • Constipation
  • Confusion
  • Bleeding gums
  • Memory loss
  • Dizziness
  • Muscle weakness
  • Vision loss
  • Fatigue
  • Pale skin
  • Decreased appetite
  • Hair loss
  • Weight loss

Although there are foods rich in vitamin B12, such as oranges, fortified cereals, milk, cheese, yogurt, and meat, if someone suffers from a serious vitamin B12, so in that case, vitamin B12 shots are a quick way to cure the deficiencies. There are multiple benefits of B12 shots, which we will discuss further in this article, but we will see the types of vitamin B12 used in these shots.

3. Types of Vitamin B12 Used In B12 Shots

There are four types of vitamin b12 forms such as methylcobalamin, adenosylcobalamin, cyanocobalamin, and hydroxocobalamin. Methylcobalamin and adenosylcobalamin are found in animal products such as milk, eggs, and meat and are easily absorbed by the body. Mostly hydroxocobalamin and cyanocobalamin are used in B12 shots and provide benefits for B12 shots in case of severe deficiency.

Hydroxocobalamin:  These are produced naturally in the digestive tract by bacteria produced by broken sources of food. It can be made synthetically by a man from microorganisms. Suppose vitamin B12 deficiency can be given in injection form to the person. In that case, it is easily converted into adenosylcobalamin and methylcobalamin by the body, and the cell absorbs it, and it’s ready to use.

Cyanocobalamin:  These are a synthetic form of vitamin B125 and are not found easily in food products. These can be given to the person in injection form in case of vitamin B12 deficiency. It consists of a cyanide molecule. We know cyanide is a kind of poison, but it is present in really minute quantities in cyanocobalamin, and that’s why it is not so harmful. These are converted into methylcobalamin and adenosylcobalamin by the body. Mainly B12 shots include the above two types of vitamin B12. Consult with your doctor about which type of vitamin B12 shot is needed for your body to gain the maximum benefits of B12 shots.

4. Benefits of B12 Shots:

There are numerous benefits of B12 shots, especially for older adults or people with a serious deficiency of vitamin B12, which cannot be fulfilled with diet or other supplements.

7 Powerful Benefits of B12 Shots you Probably Didn’t Know

4.1. Increase Energy Levels In The Body:

Our body requires glucose for energy production, and vitamin B12 aids in the process of the body converting food into glucose. This is one of the important benefits of B12 shots.

4.2. Benefits of B12 Shots For Brain Health:

Vitamin B12 is considered a vital nutrient for brain neurons. The lack of these neurons in the brain raises the problem of memory loss or dementia. A deficiency of vitamin B12 causes neuron loss, poor memory, and depression. So vitamin B12 is essential for brain health, and it also increases concentration.

4.3. Benefits of B12 Shots for Blood Health:

Vitamin B12 is responsible for generating red blood cells in our body. Red blood cells do not develop properly in case of a deficiency of vitamin B12 in our body. So due to these poorly developed blood cells in our body, blood cells become large and asymmetrical in shape. This leads to improper flow of these blood cells from bone marrow to the bloodstream, leading to the problem of megaloblastic anemia6. Anemia can cause fatigue and weakness. That’s why the balance of vitamin B12 in our body is essential to become fit. It also helps in weight gain if you suffer from weakness.


4.4. Reduced Macular Degeneration Risk:

It is a kind of eye disease that causes blindness in older people. A sufficient amount of vitamin B12 in the body reduces homocysteine in the bloodstream, which helps prevent macular degeneration. Especially older adults get the maximum benefits of B12 shots in this case.

4.5. Boost Heart Health:

Low vitamin B12 in our body leads to a higher chance of stroke or heart attack due to increased homocysteine levels. So to balance these homocysteine levels, vitamin B12 is really necessary for our body.

4.6. Benefits of B12 Shots In Skin Health:

Vitamin B12 is essential for your hair, nails, and skin health. The proper balance of vitamin B12 in our body helps in cell health, which boosts our skin.

5. Side Effects of B12 Shots:

Before taking a B12 shot, you must be completely aware of its benefits and side effects to make a well-informed decision. Some of its side effects are:

What Causes B12 Side Effects?

5.1. Mild Side Effects of B12 Shots Containing Hydroxocobalamin:

  1. Redness at the injection site.
  2. Swelling, itching, and diarrhea

5.2. Mild And Serious Side Effects of B12 Shots Containing Cyanocobalamin:

5.2.1. Mild Effects:

  1. Diarrhea
  2. Swelling

5.2.2. Serious Effects:

  1. Muscle weakness
  2. Extreme thirst
  3. Confusion
  4. Shortness of breath
  5. Headache
  6. Reddening of skin
  7. Irregular heartbeat


B12 deficiency can have serious health consequences if left untreated, so it’s important to seek medical attention if you suspect you may be deficient.

It’s important to note that B12 shots are generally considered safe, but they may cause side effects in some people, such as pain or swelling at the injection site, nausea, and dizziness. As with any supplement or medication, it’s essential to talk to your healthcare provider before starting B12 shots to determine if they are appropriate for you.


1. How long does the B12 shot last?


Simply put, how long the B12 shot will last is different for everyone. Though it differs a bit from one person to another, the effects of B12 vitamins usually last around 48 hours to 72 hours after the initial injection.


2. How fast does a B12 shot work?


B12 injections work quickly; they are the most effective way for your body to absorb Vitamin B12. Within 48 to 72 hours, your body will begin to make new red blood cells. For mild deficiencies, you may need two to three injections over several weeks to notice peak impact.


3. Which is better B12 shots or pills?


Orally-swallowed B12 tablets are just as effective as injections in the vast majority of patients, except those with digestive issues that may hamper absorption.

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  1. Hoffbrand, A. V., and B. F. A. Jackson. “Correction of the DNA synthesis defect in vitamin B12 deficiency by tetrahydrofolate: evidence in favour of the methyl‐folate trap hypothesis as the cause of megaloblastic anaemia in vitamin B12 deficiency.” British journal of haematology 83.4 (1993): 643-647. ↩︎
  2. Ermens, A. A. M., L. T. Vlasveld, and Jan Lindemans. “Significance of elevated cobalamin (vitamin B12) levels in blood.” Clinical biochemistry 36.8 (2003): 585-590. ↩︎
  3. Glinski, Juliet, Scott Wetzler, and Elliot Goodman. “The psychology of gastric bypass surgery.” Obesity surgery 11.5 (2001): 581-588. ↩︎
  4. Weetman, Anthony P. “Graves’ disease.” New England Journal of Medicine 343.17 (2000): 1236-1248. ↩︎
  5. Wierzba, Aleksandra J., Sidra Hassan, and Dorota Gryko. “Synthetic approaches toward vitamin B12 conjugates.” Asian Journal of Organic Chemistry 8.1 (2019): 6-24. ↩︎
  6. Aslinia, Florence, Joseph J. Mazza, and Steven H. Yale. “Megaloblastic anemia and other causes of macrocytosis.” Clinical medicine & research 4.3 (2006): 236-241. ↩︎

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