When Should You Take Vitamin B12?

Medically Reviewed By William C. Lloyd III, MD, FACS

Vitamin B12 is great for your entire body with benefits that include DNA production, cell metabolism, red blood cell formation, bone health, protein synthesis, and nerve function. Though it’s not common, 5 to 15% of the U.S. population has a vitamin B12 deficiency. People who are deficient in B12 report having more energy and improved mood after increasing vitamin B12 intake. B12 can also help with anemia, since it boosts red blood cell production.

Vitamin B12 is not found naturally in plant products, but you can get more B12 in your diet through vitamin-rich or vitamin-fortified foods, as well as taking supplements. Vitamin B12 binds to protein in foods. It is naturally abundant in foods from animals, including meat and dairy products. Keep in mind, evidence shows you only need to take B12 if you have low levels of the vitamin in your system.

woman in bathrobe taking vitamins or medication

Signs of Vitamin B12 Deficiency

You may be more likely to experience vitamin B12 deficiency if you follow a vegetarian or vegan diet, because B12 is in plant foods.

As you get older, you may experience a B12 deficiency if your stomach does not make enough hydrochloric acid to absorb the vitamin. People with such conditions as atrophic gastritis and pernicious anemia may also have trouble absorbing vitamin B12.

How do you know if you have a vitamin B12 deficiency? It can be hard to self-diagnose, because symptoms often develop slowly and are often attributed to the normal aging process. If you experience any of these symptoms, contact your doctor and let them know you are concerned about a B12 deficiency; and ask for a vitamin B12 blood test.

Signs of vitamin B12 deficiency can include:

How to Take Vitamin B12

Getting the benefits of vitamin B12 can be as simple as eating the right foods. Meats, fish, eggs, and dairy products are all great sources of B12. If you like clams and beef liver, they have some of the highest amounts of B12 per serving.

If you don’t eat animal products, you can try foods like fortified breakfast cereals and nutritional yeast to boost your vitamin B12 intake. Your doctor may also recommend an oral vitamin B12 supplement. Some treatments for vitamin B12 deficiency may require injections to increase your B12 levels faster.

The average daily recommended intake of vitamin B12 for adults is 2.4 micrograms. Eating a bowl of fortified cereal provides more than your daily amount of B12, since fortified cereals have up to 6 micrograms of B12 and a cup of low-fat milk contains 1.2 micrograms.

Keep in mind that vitamin B12 is a water-soluble vitamin, so any excess vitamin B12 in your system is eliminated through the kidneys. Always take B12 supplements with a full glass of water to optimize absorption. You may also want to take vitamin B12 in the morning, because it’s known to boost your energy and could interfere with your sleep if you take it at night.

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  1. Vitamin B12 deficiency can be sneaky, harmful. Harvard Health. https://www.health.harvard.edu/blog/vitamin-b12-deficiency-can-be-sneaky-harmful-201301105780
  2. Vitamin B12. National Institutes of Health Office of Dietary Supplements. https://ods.od.nih.gov/factsheets/VitaminB12-Consumer/
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  5. The Best Time to Take Vitamins. Cleveland Clinic. https://health.clevelandclinic.org/the-best-time-to-take-vitamins/
  6. TUESDAY Q & A: Vitamin B-12 deficiency more common with increasing age. Mayo Clinic. https://newsnetwork.mayoclinic.org/discussion/tuesday-q-a-vitamin-b-12-deficiency-more-common-with-increasing-age/
Medical Reviewer: William C. Lloyd III, MD, FACS
Last Review Date: 2021 Dec 14
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