How Much Vitamin B12 Should I Take?

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    Vitamin B12 can be found in many foods, but if you’re not getting enough from your diet, you need to know all the facts before you supplement.

    What is vitamin B12?

    Vitamin B12 is probably the most well known of all of the 8 B vitamins that comprise the B-complex group. The B vitamins are water-soluble, which means that the body does not store any extra. Instead it is excreted in the urine through the kidneys. All eight are all essential nutrients and since you get them in your food, it is possible for a deficiency due to diet alone. The good news is that a good B-Complex, like Care/of’s The Busy B’s can help to bridge the nutrient gap.

    The B vitamins help the body to convert food (carbohydrates) into fuel (glucose), which is then used to produce energy. They help the nervous system function properly, promote cognitive function, and are necessary for healthy skin, hair, eyes, and liver.

    Vitamin B12, also known as cobalamin, is naturally found in foods, though it can be supplemented with vitamins or added to foods, which will indicate that they are “fortified with vitamin B-12” on the product packaging.

    It works closely with vitamin B9 (folate or folic acid) in the formation of red blood cells and to help iron work more effectively in the body. It is especially important for maintaining healthy nerve cells, and it helps in the production of the body’s genetic material, DNA and RNA. B12 and folate (B9) work together to produce S-adenosylmethionine (SAMe), a compound involved in mood and immune function. Vitamin B12 also works with B6 and B9 to manage the blood levels of the amino acid homocysteine.

    Why I need vitamin B12

    Vitamin B12 is critical for a number of bodily functions, from keeping your brain and blood cells healthy to helping you to metabolize food for energy. It plays a major role in developing the central nervous system, forming red blood cells, and synthesizing DNA.

    Vitamin B12 also helps your body turn carbohydrates into glucose, thereby producing energy. It is also known to promote mood and immune function. Your body does not make vitamin B12 on its own, so you have to get it from a diet that includes meat, dairy, eggs, and fortified foods such as certain breads, cereals, milks, and juices. It is a water-soluble vitamin, so your body will flush out any extra that isn’t being used through your urine. This makes it it unlikely that you’ll consume too much of it. Still, it is important to monitor your B12 level, especially as you age.

    Vitamin B12 deficiency

    While a vitamin B12 deficiency is rare, especially in younger people, a mild deficiency is not uncommon as people age. Vitamin B12 is not made in the human body and must come from food sources such as meat, poultry, dairy, eggs, and fortified foods. A person’s inability to digest vitamin B12 may cause a deficiency. Other factors that may contribute to the poor absorption of vitamin B12 include low stomach acid (which is needed for B12 absorption), a diet low or void of any animal products, intestinal surgeries or digestive issues can contribute to malabsorption, and the use of certain medications (such as proton pump inhibitors).

    According to some sources lab levels below 200 pg/mL are considered a clinical B12 deficiency. However, there are functional practitioners ranges that are considered optimal. There are some potential symptoms that may be indicative of a B12 deficiency, but it should be noted that the symptoms can be related to other potential causes. Always talk to your doctor about health concerns. Some of the physical symptoms of a potential B12 deficiency may include fatigue, pale skin, , weight loss, sore mouth or tongue. A deficiency unaddressed can impact neurological and psychological systems as well.

    It is always a good idea to monitor your B12 level and it can be easily done with a blood test by your physician. If you are experiencing any of the symptoms of a vitamin B12 deficiency, contact your physician. Most deficiencies are easily remedied with dietary changes and supplementation.

    Health benefits of vitamin B12

    Vitamin B12 helps your body to convert carbohydrates to glucose, thus creating more energy for your body. It also plays an important role in the production of healthy red blood cells. B12 is known to maintain healthy homocysteine levels in the body.

    Vitamin B12 has been shown to support cognitive and nervous system health.

    This study of vitamin B12 and cognitive functions in old age demonstrates that maintaining optimal levels of vitamin B12 provides positive health benefits. Research suggests that optimal B12 levels can positively influence cognitive function. In a study on men and women aged 45 to 69, high vitamin B12 levels were associated with better word recall and higher verbal fluency scores.

    This study of the relationship of vitamin B12 and sensory and motor peripheral function in older adults found that adequate B12 levels are needed to maintain healthy nerve function. A large cross-sectional study performed on adults aged 72 to 83 found that a deficiency in B12 was associated with greater insensitivity to light and touch, along with worse nerve conduction amplitude and velocity.

    How much vitamin B12 should I take?

    The recommended dietary allowance (RDA) of vitamin B12 is 2.4 micrograms per day. This does not take into account any special requirements that would change the recommendation. Older people may need higher doses than younger people as the body’s ability to absorb B12 from your diet declines with age. Pregnant or breastfeeding people may also require a higher dosage. The same may be true vegans or vegetarians, since they do not eat any animal products. People with absorption issues due to medication or low stomach acid might require higher doses as well. Ideally you could get enough vitamin B12 from diet alone, but this is not always the case. Foods rich in B12 include beef, liver, kidney, chicken, shellfish, rainbow trout, salmon, tuna, clams, Greek yogurt, eggs, and cheese. There are also foods fortified with vitamin B12 such as breakfast cereal, whole grains, breads, orange juice, yogurt, milk, and many milk alternatives that are all excellent sources of B12.

    If you are considering taking a B12 supplement, ask your physician for assistance with determining the best dose for you.

    Can I take too much vitamin B12?

    The Tolerable Upper Intake Level (UL) of a supplement is the maximum daily dose that can be taken that is unlikely to cause adverse side effects in the general population. To date, no UL has been determined for vitamin B12 because of its low level of potential toxicity. Since vitamin B12 is water-soluble, the body flushes out any excess it cannot use through its urine.

    Potential side effects and adverse reactions

    Potential side effects are rare as most studies do not report any side effects. If taking high doses to treat a deficiency then there may be an increase in the potential for symptoms. If you experience any new symptoms when starting a new supplement be sure to talk to your doctor to figure out the next steps.

    Should I take a vitamin B12 supplement?

    Vitamin B12 is essential to the body’s optimal functioning and well-being. If you are following a plant based diet, looking to support cognitive and nervous system health, or energy metabolism, then B12 may be a good option to consider.

    If you think you might have a deficiency, it can easily be confirmed with a blood test from your doctor. The normal values are 160 to 950 picograms per milliliter (pg/mL), or 118 to 701 picomoles per liter (pmol/L). Normal value ranges may vary some among different labs, but your physician will be able to interpret the results and determine if B12 supplementation is necessary.

    You can also easily add more B12 rich foods to your diet if you’re interested in raising your levels naturally.

    Other sources of vitamin B12

    Vitamin B12 can be found in a variety of sources, the most obvious being a healthy diet that includes animal products (the richest sources being clams and liver), fortified foods, and nutritional yeast. The most natural way to increase your B12 levels is to increase your intake of any of these foods. But if clams and liver don’t do it for you, you prefer to eat a plant-based diet, or you can’t get enough B12 that way, there are a variety of supplement options available to you either over-the-counter or with a prescription from your physician.

    Vitamin B12 can be found in multivitamins, B-Complex vitamins, and in individual supplements. It can be administered through the nose, (intranasal form), oral tablets, capsules, soft gels, gummies, and lozenges. It is also sold under the names cobalamin and cyanocobalamin. But the most active methylated versions are listed as methylcobalamin, adenosylcobalamin, and hydroxocobalamin.

    In the case of a severe deficiency, or if you have other health issues that limit your body’s natural ability to absorb it, your physician may recommend vitamin B12 injections. The subcutaneous or intramuscular injections may be prescribed by your doctor who will recommend the dosage and the frequency of the supplementation.

    Vitamin B12 is also available in energy drinks and B12 shots, though these may come with more sugar and additives than you want and might actually contain inactive forms of B12.

    If you do decide to supplement, always choose a high-quality product with minimal, if any, additives or fillers. Care/of’s B12 The Energizer and B-Complex The Busy B’s are premium quality supplements that are rich with B vitamins and also vegan.

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    Dr. Carla Montrond Correia ND, CNS
    Medical Content Manager
    Dr. Montrond-Correia is a licensed naturopathic physician and a certified nutrition specialist (CNS). She holds degrees from University of Bridgeport, Georgetown University, and University of Saint Joseph, and supplemented her education with internships in the health and wellness space. She's focused on research, herbal medicine, nutrigenomics, and integrative and functional medicine. She makes time for exercise, artistic activities, and enjoying delicious food.
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