Can You Have Too Much B12 in Your Diet?

Vitamin B12 is a crucial vitamin used by the body to ensure optimal nerve cells and blood health. It also helps prevent a condition known as megaloblastic anemia and creates DNA genetic material. Vitamin B12 is considered safe in general, even at high doses. 

Most individuals get almost all of their required B12 through their diet, so supplements are unnecessary. But you may need more than the daily recommended amount of B12 if a healthcare provider directs you to do so.

This article discusses everything you must know about vitamin B12 and what to do if you have low vitamin B12 levels.

The benefits of vitamin B12

B12 has several benefits associated with it, whether through supplementation or diet. They include: 

Keeps eyes healthy: Deficiencies in B12 may lead to eye disease, including macular degeneration, so it is crucial to get enough.

Formation of red blood cells: Red blood cells are crucial for carrying oxygen throughout the body, so getting enough vitamin B12 can ensure the process runs smoothly.

Bone health: Your bones utilize vitamin B12 to help maintain the density of bone minerals, and deficiency over time can lead to weaker bones and an increased risk of fractures.

Staying healthy during pregnancy: Consuming enough B12 during pregnancy can help to lower the risk of significant congenital disabilities.

Metabolism and energy: Your metabolism and energy levels are vital to your overall health, and getting enough vitamin B12 helps maintain correct metabolic functioning so that energy levels remain optimal.

Mental health: Studies show that vitamin B12 is crucial in disorders and mood regulation, such as depression. Getting enough vitamin B12 can help reduce symptoms of depression and improve mood because of how it helps to synthesize and metabolize serotonin.

Hair, skin, and nail health: B12 promotes healthy cells, including hair, nails, and skin.

Brain health: B12 vitamins can also help maintain brain health by preventing the loss of neurons.

Heart health: Several of the body’s amino acids, including homocysteine, play a role in heart health. Homocysteine has been shown to increase heart disease risk if levels are too high. Vitamin B12 can help keep levels of amino acids where they need to be, mitigating the risk.

How much B12 should you take each day?

You’ll have to receive enough essential nutrients to reap the benefits of B12 in the body. The amount of B12 a person needs is dependent on their age or pregnancy status and can be broken down as follows:

Children 1-3: O.9 micrograms per day

Children 4-8: 1.2 micrograms per day

Children 9-13: 1.8 micrograms per day

Teens 14-18: 2.4 micrograms per day

Adults: 2.4 micrograms per day

Pregnant people: 2.6 micrograms per day

People who are breastfeeding: 2.8 micrograms per day

How much B12 is too much to take?

When examining vitamin B12 levels, it is difficult to say how much is too much. The vitamin is water-soluble and relatively safe at high levels because the body flushes out what is unused with water.

While there is a common recommendation, some people may need more than others based on numerous factors, including:

Specific medications


Age (older adults may require more)

Difficulty absorbing B12 into the body

People who have intestinal or stomach surgery

People with certain health disorders, including autoimmune diseases, anemia, or gastrointestinal disorders.

People in the before-mentioned groups may need more than the daily recommended allowance, but in the general population, they do not, and taking more vitamin B12 than needed is unnecessary.

Several studies have investigated high doses of B12 to see if and how it affects the body, and none has determined a particular amount that could lead to an overdose.

Taking an excess of B12

While there are no adverse health effects associated with taking an excess of B12, you are wasting money if you supplement with B12 when you don’t need to. Your body will use what is necessary and expel the rest.

Can an excess of B12 cause side effects?

Since taking high doses of B12 hasn’t been seen to affect people negatively, there are no known symptoms associated with vitamin levels that are too high.

As mentioned before, the water-soluble vitamin is expelled from the body before it can cause any issues.

Can people have blood levels that are high in vitamin B12?

Excess levels of vitamin B12 in the bloodstream are uncommon as it leaves the body through urine when it isn’t needed. People can see an increase in their B12 levels in the blood if they have certain conditions, including: 

Hepatitis: inflammation of the liver.

Cirrhosis of the liver: scarring of the liver.

Myeloproliferative disorders: diseases of the blood and bone marrow.

Conditions often present with elevated B12, but the levels do not seem to be so high they cause toxicity.

What should you do if you have low B12 levels?

Deficiencies in vitamin B12 can be detrimental to one’s overall health. Some effects of low levels of vitamin B12 include:

Difficulty walking

Weak muscles

Tingling and numbness of the feet or hands


Decreased appetite


Weight loss

A quickened heart rate



Over time, deficiencies in vitamin B12 can increase the risk of various health disorders, including:





Memory loss


Heart failure

Loss of taste and smell

Problems with vision


Loss of physical coordination

Damage to the nervous system

Certain cancers

Neural tube defects

Because of the adverse effects that can develop from not getting enough B12, it is critical to have your levels tested by a healthcare provider, eat more foods that contain the nutrient, or take supplements if you determine you are low in the vitamin. 

Foods that contain Vitamin B12

To increase the amount of B12 in your diet, you can add foods, including:


Beef liver


Nutritional yeast






Plain fat-free yogurt

Fortified breakfast cereals

Cheddar cheese

Vitamin B12 and pregnancy

Pregnant women often require more vitamin B12 than those without because it helps fetal development. Vitamin B12 deficiency increases the risk of congenital disabilities, so taking enough is crucial. Pregnant women should aim to get at least 2.6 mcg per day to ensure they and the fetus receive enough of this essential nutrient during pregnancy.

To summarize

Vitamin B12 is an essential nutrient necessary for many processes in the body. Without enough, people may experience a deficiency that can be so severe it may lead to adverse health complications, including depression, anemia, and a higher risk for certain cancers. 

Because of that, knowing how much you should be getting each day is vital to ensuring your needs are met. 

There is no clinical evidence of adverse side effects from taking too much. Since the vitamin is water soluble, anything the body does not use is expelled through urine. This means it cannot build up to severe levels in the body. Taking more than the recommended amount might not lead to severe health consequences but is unnecessary unless a healthcare provider tells you otherwise.