Fact Checked

This Dr. Axe content is medically reviewed or fact checked to ensure factually accurate information.

With strict editorial sourcing guidelines, we only link to academic research institutions, reputable media sites and, when research is available, medically peer-reviewed studies. Note that the numbers in parentheses (1, 2, etc.) are clickable links to these studies.

The information in our articles is NOT intended to replace a one-on-one relationship with a qualified health care professional and is not intended as medical advice.

This article is based on scientific evidence, written by experts and fact checked by our trained editorial staff. Note that the numbers in parentheses (1, 2, etc.) are clickable links to medically peer-reviewed studies.

Our team includes licensed nutritionists and dietitians, certified health education specialists, as well as certified strength and conditioning specialists, personal trainers and corrective exercise specialists. Our team aims to be not only thorough with its research, but also objective and unbiased.

The information in our articles is NOT intended to replace a one-on-one relationship with a qualified health care professional and is not intended as medical advice.

Vitamin B12 Benefits That You’re Probably Missing


Vitamin B12 benefits - Dr. Axe

Are you struggling with fatigue, low energy levels, mood changes and a lack of focus? This can be a sign that you’re dealing with a vitamin B12 deficiency. If that’s the case — you’re not alone. About 40 percent of people have low levels of vitamin B12, which is an issue that needs to be addressed because this is an essential vitamin for the production of red blood cells and DNA, not to mention all the vitamin B12 benefits it provides. 

Vitamin B12 deficiency is thought to be one of the leading nutrient deficiencies in the world, with a 2004 study showing that it’s a major health concern in many parts of the world, including the U.S., India, Mexico, Central America, South America and certain areas in Africa. (1) This is a big deal because vitamin B12 benefits so much of the body, and without it, those vitamin B12 benefits are lost. That’s why it’s important to get vitamin B12 foods into your diet.

So what does it do? Vitamin B12 benefits your mood, energy level, memory, heart, skin, hair, digestion and more. It is also an essential vitamin for addressing adrenal fatigue, multiple metabolic functions — including enzyme production, DNA synthesis and hormonal balance — and maintaining healthy nervous and cardiovascular systems.

Because of its wide-reaching roles within the body, a vitamin B12 deficiency can show up in many different negative symptoms, many of which are very noticeable, such as potential chronic fatigue, mood disorders like depression, and chronic stress or feeling run down.

What Is Vitamin B12?

Vitamin B12 actually exists in many forms, and it contains the mineral cobalt, which is why compounds with vitamin B12 are collectively called cobalamins. Two forms of vitamin B12 that are active in human metabolism are methylcobalamin and 5-deoxyadenosylcobalamin.

Vitamin B12 benefits the central nervous system in many important ways: It helps maintain the health of nerve cells — including those needed for neurotransmitter signaling — and helps form the protective covering of nerves, called the cell’s myelin sheath. This means that when vitamin B12 levels are low, almost every cognitive function can suffer.

Vitamin B12 also helps with digestion and heart health, so a deficiency can lead to both digestive disorders and an increased risk for heart disease. It can come in food sources, hydroxocobalimin vitamin B12 injections or as an intramuscular vitamin.

The National Institute of Health’s (NIH) Dietary Office estimates that somewhere between 1.5 percent to 15 percent of people in the U.S. are deficient in vitamin B12. (2) Other studies, like one published in the American Journal of Clinical Nutrition in 2000, indicate that this number might be even higher, with up to 39 percent of the population possibly suffering from a vitamin B12 deficiency. (3)

Top 9 Vitamin B12 Benefits

Wonder how vitamin B12 functions as a health-promoting vitamin? Vitamin B12 functions as a beneficial substance in the following ways:

1. Helps Maintain Energy Levels

Vitamin B12 benefits your metabolism because it’s needed to convert carbohydrates into useable glucose in the body. Glucose from carbohydrate foods is used as a form of energy, so this is the reason why people with vitamin B12 deficiencies often experience fatigue.

Vitamin B12 is also needed for neurotransmitter signaling that helps your muscles contract and gives you energy to go about your day without feeling tired and run down. (4)

People often wonder whether vitamin B12 benefits weight loss. Because a vitamin B12 deficiency can lead to sluggishness, chronic fatigue, and mood and appetite changes, it can be hard to lose or maintain weight with these symptoms. It’s not that increasing your vitamin B12 levels alone will make you lose weight, but correcting a deficiency will boost your energy levels and regulate your appetite so you can continue your health regime.

2. Prevents Memory Loss and Lowers Risk of Neurodegenerative Disease

A vitamin B12 deficiency may cause various neurologic and psychiatric disturbances. Because of its role in nerve health and neurotransmitter signaling, vitamin B12 benefits cognitive function and is used to lower the risk of neurodegenerative diseases, including Alzheimer’s disease and dementia. (56)

A systematic review published in International Psychogeriatrics examined 43 studies investigating the association of vitamin B12 and cognitive impairment or dementia and 17 studies reporting the efficacy of vitamin B12 therapy for these cognitive conditions. Researchers found that low vitamin B12 levels are associated with Alzheimer’s disease, vascular dementia and Parkinson’s disease. On top of this, vitamin B12 supplements were effective in correcting a biochemical deficiency and improved cognition in patients with pre-existing vitamin B12 deficiency. (7)

3. Boosts Mood and Helps the Nervous System to Properly Function

One of the most researched vitamin B12 benefits is its ability to help in healthy regulation of the nervous system, including reducing such mood disorders as depression and anxiety. Vitamin B12, along with folate, is needed as a major determinant of one-carbon metabolism, which produces the compound called SAM (S-adenosyl methionine). SAM is crucial for neurological function, dealing with stress and mood regulation. (8, 9)

Vitamin B12 is also needed for concentration and cognitive processes, such as learning, so a vitamin B12 deficiency can result in difficulty focusing and an increased risk for attention disorders.

4. Plays a Role in Maintaining Heart Health

Vitamin B12 benefits cardiovascular health in several ways, which is important considering the fact that heart disease is currently the No. 1 cause of death worldwide. Vitamin B12 helps reduce elevated homocysteine levels, which is now considered a major risk factor for heart disease. (10) Homocysteine is an amino acid, and its levels in the blood are influenced by blood levels of B-complex vitamins, including vitamin B12.

Vitamin B12 helps protect against heart disease like a heart attack or stroke by lowering high homocysteine levels in the blood. There is also some evidence that B12 can help control high cholesterol and high blood pressure levels. B vitamins are also able to control atherosclerotic diseases, in which someone experiences a dangerous buildup of plaque in the arteries. (11)

5. Needed for Healthy Skin and Hair

Vitamin B12 is essential for healthy skin, hair and nails because it plays a major part in cell reproduction. Vitamin B12 benefits skin health by reducing redness, dryness, inflammation and acne blemishes — and can be applied to the skin for psoriasis and eczema. It can also reduce hair breakage and help nails become stronger. (12)

Vitamin B12 benefits

6. Aids in Digestion

Due to its role in helping with digestive enzyme production, vitamin B12 is needed to support a healthy metabolism and the breakdown of foods within the stomach. One of the ways that vitamin B12 benefits digestion? It helps foster healthy bacteria within the gut environment. The elimination of harmful bacteria in the digestive tract — and simultaneously the presence of beneficial bacteria — is what prevents digestive disorders like inflammatory bowel disease or candida. (13)

7. Needed for a Healthy Pregnancy

Vitamin B12 is needed to create nucleic acid, or DNA — the basic genetic material that’s used to create the entire body. Therefore, vitamin B12 is not only a key nutrient for growth and development, but a vital component of a healthy pregnancy.

Vitamin B12 also interacts with folate in the body, so it may help lower the risk of birth defects, such as neural tube defects. When a pregnant woman’s vitamin B12 supply is low, the folate that’s needed for DNA synthesis remains trapped and cell replication is impaired. Studies report a two- to four-fold increased risk of neural tube defects with low vitamin B12 status. (14)

8. May Help Prevent Cancer

Vitamin B12 supplementation is now being studied as a way to help lower the risk of certain kinds of cancers, especially when taken with folate. (15) Some preliminary research shows that vitamin B12 benefits the immune system enough to potentially help prevent cancer, including cervical, prostate and colon cancers.

9. Helps Produce Red Blood Cells and Prevent Anemia

Vitamin B12 is needed to help produce a healthy level of red blood cells. It helps prevent a type of anemia called megaloblastic anemia, which results in symptoms like chronic fatigue and weakness. (16)

B12 vs. B6 vs. B Complex vs. Folic Acid

Vitamin B12:

  • Vitamin B12 is required for many important body functions, including proper red blood cell formation, DNA synthesis and neurological function.
  • Vitamin B12 deficiency can cause symptoms like chronic fatigue, muscles aches, joint pain, shortness of breath, mood chances, poor dental health, abnormal health problems and poor memory.
  • The best vitamin B12 foods include beef and chicken liver; fish like salmon, herring, mackerel and tuna; yogurt; and raw milk.

Vitamin B6:

  • Like vitamin B12, vitamin B6 (also known as pyridoxine) plays an important role in a range of physical and psychological functions, but this vitamin is essential for amino acid metabolism. Vitamin B6 benefits include its ability to help maintain a healthy metabolism, boost nerve and liver function, improve skin and eye health, and increase energy levels.
  • Vitamin B6 deficiency can cause symptoms like mood changes, fatigue, muscle pains, confusion, worsening PMS symptoms and worsening anemia symptoms. Studies also show that vitamin B6 deficiency is linked to increased heart disease, neurodegenerative diseases and neuropsychiatric disorders, like seizures, migraines and mood disorders.
  • The best vitamin B6 foods include turkey breast, grass-fed beef, chicken breast, tuna, pinto beans, chickpeas, avocado, pistachio nuts, sunflower seeds and sesame seeds.

B Complex:

  • B complex supplements contain a combination of B vitamins, including vitamin:
    • B1 (thiamine)
    • B2 (riboflavin)
    • B3 (niacin)
    • B5 (pantothenic acid)
    • B6 (pyridoxine)
    • B7 (biotin)
    • B9 (folic acid)
    • B12 (cobalamin)
  • As a whole, B vitamins benefit your metabolism and energy levels. Vitamin B was once considered a single nutrient, but scientists discovered that “vitamin B” extracts were actually made up of several vitamins, so they were given distinguishing numbers.
  • Just because the names of these vitamins all begin with “B” doesn’t mean that they are completely alike. All B vitamins have unique structures and are responsible for performing different functions. Plus, the amount we require for each B vitamin varies, so we shouldn’t be consuming equal amounts of each one.
  • What’s called a “B complex” is commonly available as a separate supplement or as part of a multivitamin.
  • All B vitamins are water-soluble, so they are flushed out of the body and dissolved in urine when you’ve consumed too much. This means that your body cannot store B vitamins, so you need to replenish them with the foods you eat.

Folic Acid:

  • Folic acid is the synthetic form of folate, or vitamin B9.
  • Folate plays an important role in cell division, and it helps make new cells by copying and creating DNA. Folate also helps the body use vitamin B12, and it’s an important vitamin for pregnancy, as it’s required for DNA synthesis.
  • Folic acid and vitamin B12 are closely connected because they both play a role in methionine synthase. Basically, vitamin B12 reactivates folic acid so it can be used by the body, and vitamin B12 depends on folic acid to fulfill this role. A deficiency in one of these vitamins will create a deficiency in the other.
  • Folate is naturally found in foods, while folic acid is the synthetic form of folate that’s found in supplements or fortified foods. Some folic acid foods include fortified rice and enriched spaghetti, and folate foods include beef liver, spinach, black-eyed peas and avocado.

Uses in Traditional Medicine

In Ayurvedic medicine, traditional Chinese medicine and traditional medicine, health problems arise when there are imbalances in a person’s flow of energy. A proper balance of energy is what allows for homeostasis. Because vitamin B12 plays an essential role in the formation of red blood cells and cell metabolism, nerve function, and the production of DNA, it’s needed by the body to sustain balance.

Instead of turning to medications and other conventional forms of medicine to treat health concerns, practitioners of natural medicine will look for signs of nutrient deficiencies first. If a patient is feeling sluggish, moody, forgetful and unable to focus, making dietary changes to allow for an increased intake of B vitamins may be recommended.

Plus, vitamin B12 deficiency is often caused by an issue with the gut and digestive system, which makes it difficult to absorb the vitamin properly. This is another reason why the patient’s dietary choices and overall balance need to be addressed. In combination with increasing vitamin B12 intake, it’s also important to remove foods that trigger inflammation and alter the health of your digestive system.

Vitamin B12 Deficiency

Vitamin B12 deficiency can be hard to detect, especially considering how common the symptoms of a vitamin B12 deficiency can be, such as feeling tired or unfocused. A diagnosis of vitamin B12 deficiency is typically based on the measurement of serum vitamin B12 levels within the blood. However, alarmingly, studies show that about 50 percent of patients with diseases related to vitamin B12 deficiency have normal B12 levels when tested. (17)

There are more precise screening options available to detect a deficiency, but these are usually not given to patients unless they have a known case of anemia or heart disease-related symptoms. (18) If you suspect you might have a deficiency but your initial blood test shows that your levels are normal, you may want to talk with your doctor about performing secondary tests, especially those that check for high homocysteine levels.

Symptoms of a vitamin B12 deficiency can include: (19)

  • Constantly feeling tired or chronic fatigue
  • Muscle aches and weakness
  • Joint pain
  • Difficulty breathing or shortness of breath
  • Feeling dizzy
  • Poor memory
  • Inability to concentrate well
  • Mood changes, like increased depression and anxiety
  • Having abnormal heart problems, such as palpitations
  • Poor dental health, including bleeding gums and mouth sores
  • Digestive problems like nausea, diarrhea or cramping
  • A poor appetite
  • A more serious deficiency can also cause a form of anemia called pernicious anemia, a serious condition that can cause memory loss, confusion and even long-term dementia.

Who is most at risk for having a vitamin B12 deficiency? Elderly people who tend to have impaired digestion are one of the most susceptible populations. This is because older people tend to produce less stomach acid that is needed to convert vitamin B12 properly.

Since animal foods are usually the best sources of vitamin B12, those who follow a vegan diet and don’t eat any animal products are also most likely to have a deficiency. Therefore, both older adults and plant-based eaters are advised to take a daily vitamin B12 supplement. (20)

Other groups that are at a higher risk of having a vitamin B12 deficiency include smokers (since nicotine can block absorption), alcoholics, those with anemia, and anyone with a digestive disorder like celiac or Crohn’s disease.

Bottom line — your ability to properly absorb vitamin B12 depends on the health of your digestive system. If you aren’t able to digest foods that contain vitamin B12, like animal meat, then you will end up with low vitamin B12 levels.

Top 10 Vitamin B12 Foods

Animal foods are the best food sources of vitamin B12, including organic, grass-fed dairy products, cage-free eggs, grass-fed meat, wild-caught fish, organic poultry and organ meats. According to the NIH, plant foods do not naturally contain vitamin B12 unless they are synthetically fortified.

Vitamin B12 can be found to some degree in fortified plant foods like nutritional yeast, fortified grain products and algae sea vegetables. However, most of these are not thought to be nearly as absorbable as natural animal sources.

According to the NIH, two steps are required for the body to absorb vitamin B12 from foods and experience the vitamin B12 benefits mentioned above:

First, hydrochloric acid in the stomach separates vitamin B12 from the protein to which vitamin B12 is attached in food. After this, vitamin B12 combines with a protein made by the stomach called intrinsic factor and is absorbed by the body. (21)

So, essentially, the health of your digestive system is just as important in absorbing and using adequate levels of vitamin B12 as the foods you’re eating are!

According to a 2007 study done by the Experiential Biology and Medicine group, vitamin B12 is a difficult nutrient to absorb, with healthy adults only being able to actually absorb and use about 50 percent of the vitamin B12 present within food sources — and sometimes much less. (22) The vitamin B12 present in foods like chicken, meat and fish was found to be the most absorbable, while eggs were shown to be somewhat poorly absorbed, with only about 9 percent of its vitamin B12 being used by the body.

Another unfortunate finding was that algae foods, such as blue-green algae that is a popular “superfood” among vegans and vegetarians, was not a very absorbable source of vitamin B12 at all. This is another reason why many vegans are told to take vitamin B12 supplements daily, even if they believe they are acquiring enough from certain plant foods, in order to prevent a vitamin B12 deficiency. (23)

Although the exact rate of absorbability depends on the person’s digestive health, here are the top food sources that provide vitamin B12:

  1. Beef liver: 1 ounce: 20 micrograms (over 300 percent DV)
  2. Sardines: 3 ounces: 6.6 micrograms (over 100 percent DV)
  3. Atlantic mackerel: 3 ounces: 7.4 micrograms (over 100 percent DV)
  4. Lamb: 3 ounces: 2.7 micrograms (45 percent DV)
  5. Wild-caught salmon: 3 ounces: 2.6 micrograms (42 percent DV)
  6. Nutritional yeast: 1 tablespoon: 2.4 micrograms (40 percent DV)
  7. Feta cheese: 0.5 cup: 1.25 micrograms (21 percent DV)
  8. Grass-fed beef: 3 ounces: 1.2 micrograms (20 percent DV)
  9. Cottage cheese: 1 cup: 0.97 microgram (16 percent DV)
  10. Eggs: 1 large: 0.6 microgram (11 percent DV)
Top 10 vitamin B12 foods - Dr. Axe

How to Overcome Deficiency

Here’s a breakdown of the best ways to overcome a vitamin B12 deficiency:

  1. Start consuming more natural food sources of vitamin B12. Foods provide a complex network of vitamins, minerals, dietary fiber and other substances that benefit health in ways that supplements usually cannot. You can prevent a vitamin B12 deficiency and get the most vitamin B12 benefits by adding good quality animal foods, like beef liver, grass-fed beef, wild-caught salmon, grass-fed lamb and raw dairy products, to your diet.
  2. Take a probiotic supplement daily. Taking a high-quality probiotic on a regular basis can help to improve the health of your gut and your body’s ability to properly absorb vitamin B12 and other nutrients.
  3. Work on healing your gut. Again, in order to properly absorb vitamin B12 and other nutrients, you need a healthy digestive system. Improve the health of your gut by cutting out inflammatory foods, add more whole foods to your diet and take a probiotic supplement.
  4. Take the right supplements. You can take a high-quality vitamin B12 supplement or take a B-complex vitamin. There are also vitamin B12 sprays available. But remember, dietary supplements might help in some serious situations to alleviate a deficiency, but it’s not a good idea to rely on them solely for your nutrient needs. Your diet is the most important factor in avoiding nutrient deficiencies.
  5. If you have a confirmed vitamin B12 deficiency, another option is intramuscular vitamin B12 injections, which can be done under the care of your doctor or health care practitioner.

Supplements and Dosage

Vitamin B12 can be taken in tablet form, in drops that you place under the tongue (called sublingual B12), in oral spray form, as gel formulations or even in the form of injection. You can use any of these types of vitamin B12 supplements, but make sure you are choosing a high-quality product from a reputable source. If you are curious about vitamin B12 injections, talk to your doctor about confirming a deficiency and how to go about this process. And keep in mind that sometimes seniors do better supplementing with drops and oral spray forms of vitamin B12 because they have trouble absorbing the vitamin from the stomach.

For adults who are looking to boost their vitamin B12 levels with something other than whole foods, take vitamin B12 as part of a whole foods-based B-complex supplement or a high-quality, whole foods-based multivitamin. These will contain the full spectrum of B vitamins that all work together within the body to carry out functions and balance one another, hence the “complex” name this group is given. Within a vitamin B-complex supplement, you’ll find other important B vitamins — like biotin, thiamine, niacin and riboflavin — that require one another to be present for the best results.

Compared to other vitamins, we don’t need a very large amount of vitamin B12 — but we do need to replenish our supply just about every single day. B vitamins are water-soluble and flushed out of the body somewhat easily, so to maintain levels of the recommended amount within the bloodstream and prevent a vitamin B12 deficiency, we need to eat food sources of B vitamins often.

According to the NIH, the recommended dietary allowance (RDA) for vitamin B12 is: (24)

  • Infants 0–6 months: 0.4 microgram
  • Infants 7–12 months: 0.5 microgram
  • Toddlers 1–3 years: 0.9 microgram
  • Children 4–8 years: 1.2 micrograms
  • Children 9–13 years: 1.8 micrograms
  • Adult men and women over age 14: 2.4 micrograms
  • Women who are pregnant: 2.6 micrograms
  • Women who are breastfeeding: 2.8micrograms

The NIH recommends that adults over 50 years take a daily vitamin B12 supplement or consume foods fortified with vitamin B12. The recommendation is to take between 25–100 micrograms per day, as this amount has been shown to maintain healthy levels of vitamin B12 levels in older people.

Can I Have Too Much Vitamin B12?

Because vitamin B12 is a water-soluble vitamin, the body has the ability to flush out (through our urine) any excess that it doesn’t need. As a result, vitamin B12 is considered safe and non-toxic, although it’s still always best to stick to the recommended amount and not take large doses of any supplement without consulting with a doctor first. Although vitamin B12 side effects are rare, some people experience headache, swelling, anxiousness and itching when they’ve consumed too much vitamin B12 or are having a reaction to a dietary supplement.

Also, keep in mind that some people have trouble properly absorbing vitamin B12 because of digestive issues. For these people, taking more and more vitamin B12 isn’t going to solve their problem. They’ll have to identify the reason why they’re struggling with a deficiency in the first place, which may be an issue with their gut health.


The best food sources of vitamin B12 are animal products, like organic meats and wild-caught fish. Cooking with nutritional yeast is another great way to increase your vitamin B12 levels when you aren’t eating meat. Here are some delicious recipes that contain a good amount of vitamin B12:

Risks and Side Effects

Vitamin B12 absorption can be hindered when someone has a history of alcoholism or heavy smoking. In addition to alcohol and nicotine, long-term antibiotic use can also reduce the ability of the stomach to absorb and use vitamin B12. For this reason, anyone who has used stomach acid-controlling drugs may want to talk to their doctor about needing vitamin B12 supplements.

Potassium supplements can also reduce absorption of vitamin B12 benefits, so if you take large amounts of potassium in supplement form, you should watch out for a possible vitamin B12 deficiency. Potassium from food sources shouldn’t cause a problem, but very high amounts may set someone up for a vitamin B12 deficiency.

Final Thoughts

  • Vitamin B12 is a water-soluble nutrient in the vitamin B complex that the body needs in small amounts to function properly.
  • Vitamin B12 benefits your energy levels, mood, memory, heart, hair, skin and digestion. It’s also essential for the production of DNA and red blood cells.
  • Vitamin B12 deficiency can lead to a number of health issues, including chronic fatigue, mood disorders, neurodegenerative disorders, heart issues, anemia and neural tube defects in infants.
  • To reverse a vitamin B12 deficiency, consume more natural sources of vitamin B12, including beef liver, organic meats and wild-caught salmon. You should also take a probiotic daily and work on the health of your gut by eliminating inflammatory foods.
  • If you are at risk of a vitamin B12 deficiency because of your dietary choices or age, consider taking a whole foods-based B complex supplement.

Read Next: Iron Deficiency: Is It to Blame for Your Low Energy?

Josh Axe

Get FREE Access!

Dr. Josh Axe is on a mission to provide you and your family with the highest quality nutrition tips and healthy recipes in the world...Sign up to get VIP access to his eBooks and valuable weekly health tips for FREE!

Free eBook to boost
metabolism & healing

30 Gluten-Free Recipes
& detox juicing guide

Shopping Guide &
premium newsletter

More Nutrition