Are Vitamin B12 Injections Good or Bad?

Are Vitamin B12 Injections Good or Bad?

We’ve all heard about vitamin B12 injections. They’re quite popular.

Many people consider vitamin B12 injections a safety net – one that ensures that they have sufficient nutrient intake.

The vitamin B12 supplement market is a huge one, because of the widespread deficiency.

Very many people get regular vitamin B12 injections.

It is believed to boost energy, and also help with weight loss and brain function.

In this article, we will consider what vitamin B12 is and whether it is safe for you or not.


What is vitamin B12 and what purpose does it serve?

Another name for vitamin B12 is cobalamin. It is a water-soluble vitamin.

Vitamin B12 plays an important role in DNA production, brain function, and the production of red blood cells.

Vitamin B12 has different chemical forms, but they all contain cobalt – a mineral.

Vitamin B12 is usually stored in the liver. It can be stored there for a long time, so a deficiency takes time to develop (1).

Vitamin B12 deficiency

People are advised to take up to 6 micrograms of vitamin B12 daily. This is the recommended daily intake (RDI).

Vitamin B12 deficiency is very common among vegetarians or vegans.

Studies suggest that over 90% of vegetarians or vegans have a deficiency of vitamin B12 (2, 3).

Why is this so? Well, it happens that vitamin B12 is 100% natural. This means that it is only found naturally in animal foods.

Vegetarians and vegans are not the only vitamin B12-deficient people. Some meat eaters absorb vitamin B12 poorly (4, 5).

Compared with other nutrients, vitamin B12 absorption depends on a substance called intrinsic factor. The intrinsic factor is a protein produced in your stomach.

When you eat food containing vitamin B12, the intrinsic factor in your stomach binds to it and absorbs it into your blood. If your body doesn’t produce a sufficient amount of intrinsic factors, you may become deficient in vitamin B12.

Vitamin B12 deficiency is very common among the elderly because the absorption of this nutrient decreases as a person gets older (6, 7, 8, 9, 10, 11).

The risk of vitamin B12 deficiency is also high in those who have had a weight loss surgery, or intestinal surgery. People with gut diseases like celiac disease or Crohn’s disease are also at risk (12, 13, 14, 15).

A vitamin B12 shot is very effective

When left untreated, a vitamin B12 deficiency can result in complications such as pernicious anemia or neurological conditions. Both issues occur when you don’t have sufficient B12 to produce an adequate number of red blood cells for your body (16).

Getting these shots is the commonest way to treat a deficiency or even prevent one. Your doctor will prescribe the injections and administer them intramuscularly.

The shots are usually given as cyanocobalamin or hydroxocobalamin. These injections can raise the level of B12 in the blood, and also prevent or reverse a vitamin B12 deficiency.

Potential health benefits of vitamin B12

Without a doubt, vitamin B12 plays a very vital role in the human body. As such, a deficiency of this important nutrient may affect your health.

Studies have linked low blood levels of B12 to several health issues:

Brain function

Vitamin B12 deficiency is associated with a decline in cognitive function.

Recent studies have found an association between low levels of B12 in the blood and the onset of dementia (17, 18).

Results from these studies are mixed and people with normal brain function may not necessarily benefit from treatment with vitamin B12 (19, 20, 21).


Several studies have suggested that low levels of vitamin B12 may contribute to depression.

But then, a particular review found that vitamin B12 did not help relieve the symptoms of depression whatsoever.

However, researchers suggested that long-term intake of vitamin B12 could prevent an individual from relapsing into depression (22).

Currently, very little research has been done in this area. There is a need for high-quality studies to determine whether vitamin B12 deficiency contributes to depression (23).


Osteoporosis is a condition characterized by loss of bone mass. This causes weakness of the bone and a high risk of fractures.

Studies have shown that low levels of vitamin B12 contribute to a reduction in bone mass (24).

Vitamin B12 has therefore been recommended for the prevention of osteoporosis despite the mixed results yielded by studies in this regard (25, 26, 27).

Age-related macular degeneration

This condition causes loss of central vision.

Consumption of vitamin B12 is important for individuals above the age of 50 because it is believed to maintain good vision and prevent macular degeneration as well.

In one study, 5,200 women were given 1,000 mcg of vitamin B12 every day, together with folic acid and other B vitamins (28).

After 7 years, it was discovered that their risk of developing age-related macular degeneration had decreased by 35%.

While it is true that other nutrients played a role in this, it does suggest the importance of getting adequate vitamin B12.

Any side effects?

Well, vitamin B12 injections are quite safe. There’s no risk of major side effects.

In rare instances, however, side effects may be experienced due to sensitivity or allergic reactions (29, 30). If you experience side effects from vitamin B12 injections, consult your healthcare provider without delay.

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