Vitamin B12 Benefits: 13 Ways It Helps, Based On Science

Medically Reviewed By Dr. Abby Kramer, DC
Written by Ravi Teja Tadimalla

Vitamin B12 is an essential nutrient. Its deficiency is a severe problem in the Indian subcontinent, Central and South America, Mexico, and selected parts of Africa (1). The nutrient supports your mood and memory, promotes heart health, and may help in the treatment of skin diseases.

Most adults need 2.4 micrograms of vitamin B12 regularly (2). In this post, we will discuss what science states about the benefits of vitamin B12. We will also look into the food sources of vitamin B12 and the symptoms of a deficiency.

What Is Vitamin B12? How Does It Help?

Vitamin B12, also known as cobalamin, helps in the proper functioning of the body’s blood cells and nerves. It also plays a role in DNA synthesis (3).

The vitamin is also known to prevent megaloblastic anemia, a type of anemia that makes people weak. Studies have shown that a deficiency in this nutrient could lead to the condition (4).

Vitamin B12 is absorbed in the body in two steps. In food, this vitamin is attached to a protein. The hydrochloric acid in the stomach separates vitamin B12 from this protein. The vitamin then combines with another protein made by the stomach (called the intrinsic factor). It is then absorbed in the body (5).

Individuals with pernicious anemia (a decrease in red blood cells) may be deficient in vitamin B12, as their bodies do not have the ability to produce the intrinsic factor (3).

Vitamin B12 is important for performing various bodily functions. In the following section, we will discuss them in detail.

What Are The Health Benefits Of Vitamin B12?

1. Helps In The Formation Of Red Blood Cells

Vitamin B12 (along with folate) helps in the formation of red blood cells. Without enough vitamin B12, red blood cells do not divide normally as they are supposed to and become too large. This makes them difficult to get out of the bone marrow (6).

This can result in fewer red blood cells in the bloodstream to carry oxygen to the body, leading one to feel tired and weak. This condition is also called pernicious anemia, and if not treated, it can damage the brain, heart, and other organs of the body (6).

2. May Prevent Birth Defects

Vitamin B12 is one of the crucial ingredients during pregnancy. A deficiency of this vitamin may cause infertility and recurrent abortions (7).

Starting pregnancy with a vitamin B12 deficiency may increase the risk of neural tube defects in the newborn. It may also lead to preterm delivery. The deficiency in the mother may also cause the same in the newborn if sufficient vitamin B12 is not available in breast milk. However, these implications need more research (7).

Women with vitamin B12 levels lower than 300 ng/L have a higher risk of delivering infants with birth defects (8). Increasing B12 levels beyond this may reduce the risk, though more research is warranted (8).

Vitamin B12 is required to create the new maternal and fetal cells and prevent neural tube defects in the newborn (9). It works together with folate to achieve this. A deficiency of vitamin B12 can also lead to folate deficiency, and this adversely affects pregnancy.

The vitamin may treat nausea and morning sickness, which are often associated with pregnancy. However, research in this aspect is limited.

3. Might Promote Skin Health

Vitamin B12 deficiency has been associated with changes in the skin. The most common symptom is hyperpigmentation (10).

Other dermal complications of this deficiency include vitiligo and other skin lesions (11), (12).

Vitamin B12 can also help treat some serious skin ailments. One study found that a vitamin B12 cream could reduce the extent and severity of eczema. This was especially true in the case of eczema in children (13).

You can get the cream from a pharmacy. Apply it to the affected areas twice a day. Make sure you consult your doctor. B12 also decreases inflammation and its side effects, and this is one reason it can counteract eczema.

Vitamin B12 may also help reduce shingles pain. Anecdotal evidence suggests that taking 1000 mcg of vitamin B12 on a daily basis may help treat the condition. However, as research is limited, we recommend you check with your doctor before using it.

Studies suggest that folic acid and vitamin B12, along with sun exposure, can induce repigmentation (14).

Vitamin B12 may also help fight cellulite, but there are limited studies to prove this.

4. May Improve Hair Health

Vitamin B12 helps in the formation of red blood cells. Some believe this may promote hair growth.

Vitamin B12 deficiency was observed in those with hair loss (15). At the base of hair follicles, we have tiny blood vessels that connect to the roots of each hair strand. These blood vessels carry oxygen to the hair, thereby boosting hair growth and preventing hair fall.

5. May Promote Heart Health

Vitamin B12 has shown potential as a heart disease treatment. The nutrient lowered homocysteine (a particular amino acid), the high levels of which could elevate the risk of ischemic heart disease (16).

Deficiencies of B vitamins, in general, were linked to higher homocysteine levels and an increased risk of stroke (16). This may also cut down the long-term costs associated with expensive medical treatments.

Vitamin B12 was also found to reduce blood pressure in preschool children (17).

6. May Aid Diabetes Treatment

Though there is no direct link between vitamin B12 and diabetes treatment, the nutrient may treat diabetic retinopathy (damage of blood vessels in the eye) (18).

It may aid the treatment of diabetic neuropathy (nerve damage in the legs and feet), though further research is warranted (19). Anecdotal evidence suggests that the vitamin may also treat some of the symptoms of neuropathy, including numbness, pain, and a prickling sensation.

Vitamin B12 reduces homocysteine levels in the blood, which can otherwise lead to retinopathy (20).

More interestingly, metformin, a commonly prescribed diabetic drug, may cause vitamin B12 deficiency (21). This is why it might be a good idea to supplement it, especially in the case of diabetes. Pernicious anemia is vitamin B12 deficiency experienced in the case of type 1 diabetes (22).

7. May Help Maintain Bone Health

Low plasma levels of vitamin B12 have been linked to lower bone mineral density in humans. Studies suggest that the vitamin may affect bone formation. It has also been linked to osteoblastic activity (bone formation) (23).

High homocysteine levels and low vitamin B12 levels have also been associated with osteoporosis (24). Since vitamin B12 helps lower homocysteine levels, it may play a beneficial role here.

In a study conducted on older women, lower levels of vitamin B12 were linked to increased hip bone loss (25).

8. May Help Prevent Macular Degeneration

Age-related macular degeneration has been associated with reduced plasma vitamin B12 levels and increased homocysteine levels. Intake of B12 supplementation may prevent the condition (26). However, more thorough studies are needed to understand the mechanism.

Another study also states that high levels of homocysteine may increase the risk of age-related macular degeneration (27). Since vitamin B12 helps lower the levels of this amino acid, it could be helpful in the treatment of AMD.

In another study in women, daily supplementation with folic acid, vitamin B12, and vitamin B6 over a seven-year period was found to reduce the risk of age-related macular degeneration (28).

9. May Boost Brain Health

Studies show that supplementing with vitamin B12 along with antidepressants may improve depressive symptoms. B12 deficiency may be associated with depression (29).

Adequate vitamin B12 levels may also increase the probability of recovery from depression. However, we need more studies to confirm this finding (30).

The vitamin may also have a beneficial effect on mood. It is believed the vitamin produces brain chemicals responsible for a better mood, though we need more research to understand the mechanism. Anecdotal evidence suggests that it may help treat stress and certain anxiety disorders.

Vitamin B12, when combined with omega-3 fatty acids, could also slow down memory decline in adults. The nutrients also slow down the progression of mild cognitive impairment (31).

Another study states that the vitamin can prevent brain volume loss in the elderly. Individuals taking adequate vitamin B12 had a reduced risk of brain shrinkage/atrophy (32).

Vitamin B12 deficiency may also lead to dementia and Alzheimer’s, although more studies are needed to understand the mechanism (33), (34).

As vitamin B12 also aids cell production (a process called methylation), it may help improve the symptoms of autism (35).

10. May Help With Energy Production

Vitamin B12 plays a role in cellular energy production (36). However, there is no research stating that it may boost energy levels or improve athletic performance, as popularly believed.

Some research states that vitamin B12 deficiency could lead to increased levels of fatigue (37).

11. May Improve Sleep

There is limited research in this aspect. However, one study states that adequate vitamin B12 levels may improve sleep-wake rhythm disorders (38). This study has been conducted only on two patients, so we need more large-scale studies to understand the impact this vitamin can have on sleep quality.

It is believed that a deficiency of B12 may cause insomnia. However, more research is needed to establish the link.

12. May Help In The Treatment Of Fibromyalgia

It is believed that low levels of vitamin B12 may lead to fibromyalgia and chronic fatigue syndrome. There is a lack of research in this aspect.

One study states that vitamin B12 injections may work as analgesics, thereby aiding the treatment of fibromyalgia (39).

Other research also links fibromyalgia to higher levels of homocysteine in the blood (40). As vitamin B12 lowers homocysteine levels, it may potentially aid in the treatment of fibromyalgia.

13. May Help Improve Symptoms Of Tinnitus

Tinnitus is a condition characterized by a buzzing sensation in the ears. One study states that vitamin B12 may improve the symptoms of tinnitus (41).

The deficiency of vitamin B12 has been linked to chronic tinnitus and noise-induced hearing loss.

Insufficient Evidence For The Following

14. May Stabilize Digestive Health

Vitamin B12 is believed to help with the production of digestive enzymes, which promote digestive health and ensure the proper breakdown of food. The nutrient could foster the gut environment by promoting the growth of healthy gut bacteria.

It is also believed to eliminate the harmful bacteria in the gut, possibly preventing other digestive issues like inflammatory bowel disease.

15. May Help With Weight Loss

Though we need more research, some reports state that vitamin B12 helps the body convert fat into energy and also aids the breakdown of carbs.

The vitamin may boost your metabolism, and some believe this may help with weight loss.

However, please consult your doctor before using B12 for this purpose.

16. May Prevent Mosquito Bites

Though we don’t know if it can ease mosquito bites, some believe vitamin B12 may repel mosquitoes. It is thought to exude a mosquito repellent-like smell. However, we suggest you talk to a specialist before using it for this purpose.

What Are The Food Sources Of Vitamin B12?

The following are some of the best food sources of vitamin B12 (42):

  • Beef and chicken liver (3 ounces contain 3,375% RDA of the vitamin)
  • Salmon (A 108-gram filet contains 821% RDA)
  • Tuna (3 ounces contain 385% of the RDA)
  • Organic yogurt (1 container of 170 grams contains 53% of the RDA)
  • Raw milk (1 cup contains 41% of the RDA)
  • Lamb (3 ounces contains 34% of the RDA)
  • Low-fat yogurt (8 ounces contains 18% of the RDA)
  • Egg (1 large whole egg contains 10% of the RDA)
  • Roasted chicken breast (3 ounces contains 5% of the RDA)

Including these foods in your diet can help you meet your regular vitamin B12 requirements. But what if you don’t? How do you know you are deficient in this vitamin?

What Are The Symptoms Of Vitamin B12 Deficiency?

The following are some of the most common symptoms of the deficiency:

  • Muscle aches
  • Weakness/chronic fatigue
  • Poor memory
  • Dizziness
  • Anxiety and mood swings/depression
  • Heart palpitations
  • Nausea and abdominal cramping
  • A poor appetite

Taking adequate vitamin B12 can help you avoid these symptoms. Find out the recommended dosage in the next section.

What Is The Recommended Vitamin B12 Dosage?

The following table can help you with the details (2):

Age Group
0 to 6 months
8 ounces
7 to 12 months
0.5 mcg
1 to 3 years
0.9 mcg
4 to 8 years
1.2 mcg
9 to 13 years
1.8 mcg
14 years and older
2.4 mcg
Adult and adolescent pregnant females
2.6 mcg
Adult and adolescent lactating females
2.8 mcg

What About Vitamin B12 Shots? Who Needs Them?

These are the synthetic versions of the vitamin. You can take vitamin B12 from foods or acquire the vitamin from a man-made version of the nutrient known as cyanocobalamin.

Vitamin B12 shots are nothing but injections containing very high amounts of cyanocobalamin. These shots can quickly boost the vitamin B12 levels in the individual.

Who needs them? You need these shots only if you are severely deficient (or are at risk) in vitamin B12. Vitamin B12 injections are available only by prescription, which means a clinical diagnosis is a must. You can’t (and shouldn’t) administer the shots on your own without the advice of a doctor or dietitian (43).

The following factors can increase the risk of vitamin B12 deficiency:

  • Smoking
  • Alcohol abuse
  • Sticking to a vegetarian or vegan diet
  • Aging
  • Thyroid disorder
  • People on certain diabetes medications
  • Gastrointestinal disorders like Crohn’s disease
  • Surgical removal of parts of the stomach

One major benefit of vitamin B12 shots is that they bypass the stomach and are directly absorbed into the bloodstream. Hence, in case you have gastrointestinal issues or had stomach surgeries, these shots could be a better option over oral supplements.

Side Effects Of Excess Vitamin B12

Vitamin B12 is water-soluble. This means that excess of it can pass out of your system through urine. Vitamin B12 has not shown to cause any harm. However, certain medications can interfere with your body’s ability to absorb vitamin B12. The most common of these include antiepileptic drugs (44).

Vitamin B12 can also interfere with metformin, the anti-diabetes drug (21). It can also interfere with Proton Pump Inhibitors, drugs used to treat acid reflux and peptic ulcers (45).


The B vitamins are a powerful pack. They are vital for optimal health. One of them is vitamin B12, which you ought to include in your diet. Though severe deficiency of vitamin B12 is very rare (as your liver stores years’ worth of vitamin B12), it is important you are conscious about its intake.

Frequently Asked Questions

Is vitamin B12 water-soluble?

Yes, B12, just like other B vitamins, is water-soluble. This simply means that having an overdose of vitamin B12 is highly unlikely as it dissolves in water, and the remaining amount is passed out through urine.

What is the best time to take a vitamin B12 supplement?

In the mornings, after breakfast, or during lunch. You may also take vitamin B12 during the night. But since they promote energy generation, taking it in the day could be ideal (information on this is mixed, though).

Vitamin B12 supplements may work between 48 to 72 hours, especially if they are taken by someone who is deficient in the vitamin.

Is too much vitamin B12 bad for you?

Not really. As we discussed, B12 is a water-soluble vitamin. Maintain your dosage as per the recommended levels or as directed by your healthcare provider.

Is vitamin B12 good for treating erectile dysfunction?

There is no research on this. If you are going to use the vitamin for treating ED, make sure to consult your doctor.

Can vitamin B12 cause pimples?

There is no evidence here. If you experience pimples, it could mean some underlying condition. Consult a dermatologist.


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Ravi Teja Tadimalla is an editor and a published author. He graduated from SRM University, Chennai, and has been in the digital media field for over six years. He has a Professional Certificate in Food, Nutrition & Research from Wageningen University. He considers himself a sculptor born to chip away at content and reveal its dormant splendor. He started his career as a research writer, primarily focusing on health and wellness, and has over 250 articles to his credit. Ravi believes in the great possibilities of abundant health with natural foods and organic supplements. Reading and theater are his other interests.