Vitamin B12 Dosage: What Is the Proper Daily Amount?

Vitamin B12, also known as cobalamin, is an essential vitamin for humans. It’s vital for maintaining energy levels, metabolism, hormone balance, mood, digestion and skin health. But without enough of the nutrient, we can miss out on the many vitamin B12 benefits. In fact, being deficient in B12 can lead to major health issues, from improper growth and development to cognitive impairment. So what the proper vitamin B12 dosage?

Although a balanced diet including a variety of foods will generally supply enough vitamin B12 for most people, supplementation is sometimes necessary for certain age groups and circumstances or for those with underlying health conditions. That’s why it’s important to know what vitamin B12 dosage is right for your specific needs. How do you find out? Read on to learn all about vitamin B12 dosage recommendations and more.


Vitamin B12 dosage - Dr. Axe

Why You Need Vitamin B12

Vitamin B12 plays many important roles in your body. It’s an essential vitamin for the production of red blood cells and DNA; is needed to maintain the nervous, cardiovascular and digestive systems; and promotes hormonal balance.

Your body needs vitamin B12 to thrive, but about 26 percent of the general popular is living with a vitamin B12 deficiency. A deficiency in vitamin B12 is hard to detect because it can cause common symptoms, like feeling tired, having trouble focusing, experiencing mood changes and dealing with muscle aches.

Here’s a rundown of the top reasons why you need vitamin B12:

Vitamin B12 Dosage Recommendations

You may be confused about your personal recommended daily dosage of vitamin B12. Well, stages of life and lifestyle changes impact the amount of vitamin B12 you need in order to avoid deficiency. That means that your vitamin B12 requirements will change throughout the course of your life.

The National Institutes of Health recommends the following vitamin B12 dosages for each category:

Infants, Children and Teens

The recommended daily vitamin B12 dosage for infants, children and teens is as follows:

  • Birth to 6 months: 0.4 micrograms
  • Infants 7–12 months: 0.5 micrograms
  • Children 1–3 years: 0.9 micrograms
  • Children 4–8 years: 1.2 micrograms
  • Children 9–13 years: 1.8 micrograms
  • Teens 14–18 years: 2.4 micrograms

Vitamin B12 is essential for many body functions in babies, children and teens, including proper growth and brain function. A deficiency is associated with an increased risk of adverse child health outcomes, according to research published in Advances in Nutrition. Dietary intake of vitamin B12 through breast milk, infant formula and table foods is vital.

Adults Ages 18–50

The recommended daily dosage for adults over 18 years old is 2.4 micrograms. Most adults consume at least this amount from their diets alone, given that they eat animal products like meats, seafood, dairy and eggs.

Adults with small bowel disorders, low stomach acid levels or those who have had gastric surgery may not be able to absorb the B vitamin properly and are at a greater risk of deficiency. These people may benefit from taking a B12 supplement. If you take acid-reducing medications, talk to your doctor about increasing your vitamin B12 levels.

Adults Over 50 Years Old

Adults over 50 are at an increased risk of vitamin B12 deficiency because they tend to produce less stomach acid, which is needed to convert the vitamin properly. This means that adults over 50 years old need to consume even higher amounts of vitamin B12 daily.

Another group that’s more vulnerable to a vitamin B12 deficiency is people who follow a vegan or vegetarian diet. Most of the best sources of vitamin B12 are animal products (like fish, meat, eggs and dairy products), so plant-based eaters are advised to take a daily vitamin B12 supplement to ensure that they get enough of the essential vitamin.

Studies suggest that for elderly people, taking 125–250 micrograms of vitamin B12 is effective for maintaining needed levels and avoiding deficiency. For older adults who are already deficient, taking one milligram of vitamin B12 daily for a month has been shown to reverse the deficiency and appears to be safe and without side effects.

Pregnant Women

Research shows that low vitamin B12 status is a risk factor for birth defects resulting from improper neural tube development. The developing embryo is thought to be one of the groups that’s at the greatest risk of vitamin B12 deficiency. For this reason, it is recommended that pregnant women get 2.6 micrograms of vitamin B12 daily.

Breastfeeding Women

The recommended vitamin B12 dosage for breastfeeding women is 2.8 micrograms daily. Nursing mothers need more vitamin B12 in order to pass it to their infants.

Breastfeeding moms with a known vitamin B12 deficiency may need to supplement in order to correct their levels. Research suggests that higher daily doses of 50–100 micrograms may be needed in cases of maternal deficiency. Talk to your health care provider if you are a nursing mother who may have a vitamin B12 deficiency due to dietary restrictions or gastrointestinal issues.

Vegans and Vegetarians

Because most vitamin B12 foods come from animals, people following a vegan or vegetarian diet should take a B12 supplement in order to avoid deficiency.

According to a review published in Nutrients, for healthy vegans and vegetarians to meet the daily requirement for vitamin B12, taking one oral dose of 50–100 micrograms daily appears to be sufficient.

Vitamin B12 Dosage for Certain Conditions

Certain health conditions increase the risk of vitamin B12 deficiency. This is usually an issue of malabsorption or taking medications that interfere with the absorption of vitamin B12. Sometimes, dietary changes are needed to ensure that people with certain conditions consume enough vitamin B12, and other times a B12 supplement is recommended.

Fatigue: People with a B12 deficiency may experience fatigue or lack of energy. Research shows that to correct a deficiency, taking one milligram daily for one month is effective. This can be followed by a maintenance dose of 125–250 micrograms per day.

Depression: Research shows that patients with major depression have low folate and vitamin B12 status. According to a review published in the Journal of Psychopharmacology, oral doses of 800 micrograms of folic acid and one milligram of vitamin B12 daily may help improve treatment outcomes for depression.

Gastrointestinal issues: People with gastrointestinal disorders, like Crohn’s disease and celiac disease, may have issues absorbing vitamin B12 from food. People who have had gastrointestinal surgery may also have problems absorbing vitamin B12 from foods. Patients with gastrointestinal issues may receive one-milligram doses of vitamin B12, in either injection or oral forms.

Pernicious anemia: This is a condition that affects about 1 percent to 2 percent of older adults. Because people with pernicious anemia cannot properly absorb vitamin B12 in the gastrointestinal tract, they are usually treated with vitamin B12 injections.

B12 Injection Dosage

Vitamin B12 injections are shots that contain high doses of B12 and are administered to elevate vitamin levels in deficient patients quickly. They are also used for patients who are unable to absorb vitamin B12 from foods or oral supplements properly.

B12 injection dosage is based on the patient’s level of deficiency, response to B12 supplementation and medical condition. The dosage is typically decided by a doctor, and the injections are given at a clinic or doctor’s office. Injections are usually given weekly or monthly. But research shows that injections may not be more effective than oral supplementation. One study found that taking 1,000–2,000 micrograms orally in properly timed doses helped improve B12 levels as much as injections.


According to the Institute of Medicine, no adverse effects are associated with vitamin B12 intake from food and supplements in healthy individuals. Vitamin B12 is a water-soluble vitamin, so if you consume too much, your body should be able to flush it out through urine.

Some people may experience side effects from taking very high doses of vitamin B12 or receiving B12 injections above the vitamin B12 dosage recommendations. These potential vitamin B12 side effects include headache, rash, itchy skin, dizziness, swelling, anxiety and cold symptoms.

If you are vitamin B12 deficient, it’s important to address the underlying causes of your deficiency. Simply increasing your B12 intake, either with foods, supplements or injections, will not solve your problem if you are unable to absorb the vitamin properly.

If you do not have an underlying issue that decreases your ability to absorb vitamin B12, then the ideal and safest way to consume enough of the nutrient is through whole food sources, like animal meat, seafood, organic dairy products and eggs.

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