Vitamin B12 is an essential vitamin found in foods such as meat, fish, and dairy. It can also be made in a lab and is often taken with other B vitamins.
Vitamin B12 is required for the function and development of many parts of the body, including the brain, nerves, and blood cells. Methylcobalamin is the active form of vitamin B12. Cyanocobalamin, which must be processed by the body into the active form, is the most common type used in supplements.
People commonly use vitamin B12 for vitamin B12 deficiency, cyanide poisoning, and high levels of homocysteine in the blood. It is also used for canker sores, cataracts, Alzheimer disease, osteoporosis, fatigue, and many other conditions, but there is no good scientific evidence to support most of these other uses.
- Common Searches:
- Alpha Lipoic Acid
- Apple Cider Vinegar
- Black Cohosh
- Calcium
- Chromium
- Coenzyme Q - 10
- DHEA
- Flaxseed
- Folic Acid
- Ginko
- Glucosamine
- Melatonin
- Niacin
- Magnesium
- Probiotics
- Red Yeast Rice
- St. John's Wort
- Vitamin C
- Vitamin D
- Vitamin E
You Might Also Like
View More
CONDITIONS OF USE AND IMPORTANT INFORMATION: This information is meant to supplement, not replace advice from your doctor or healthcare provider and is not meant to cover all possible uses, precautions, interactions or adverse effects. This information may not fit your specific health circumstances. Never delay or disregard seeking professional medical advice from your doctor or other qualified health care provider because of something you have read on WebMD. You should always speak with your doctor or health care professional before you start, stop, or change any prescribed part of your health care plan or treatment and to determine what course of therapy is right for you.
This copyrighted material is provided by Natural Medicines Comprehensive Database Consumer Version. Information from this source is evidence-based and objective, and without commercial influence. For professional medical information on natural medicines, see Natural Medicines Comprehensive Database Professional Version.
© Therapeutic Research Faculty 2020.
Overview
Vitamin B-12 (cobalamin) plays an essential role in red blood cell formation, cell metabolism, nerve function and the production of DNA, the molecules inside cells that carry genetic information.
Food sources of vitamin B-12 include poultry, meat, fish and dairy products. Vitamin B-12 is also added to some foods, such as fortified breakfast cereals, and is available as an oral supplement. Vitamin B-12 injections or nasal spray might be prescribed to treat vitamin B-12 deficiency.
Vitamin B-12 deficiency is not common in the U.S. However, people who follow a vegetarian or vegan diet might be prone to deficiency because plant foods don't contain vitamin B-12. Older adults and people with digestive tract conditions that affect absorption of nutrients also are susceptible to vitamin B-12 deficiency.
Left untreated, a vitamin B-12 deficiency can lead to anemia, fatigue, muscle weakness, intestinal problems, nerve damage and mood disturbances.
The recommended daily amount of vitamin B-12 for adults is 2.4 micrograms.
Evidence
Research on the use of vitamin B-12 for specific activities and conditions shows:
- Heart and blood vessel disease. Researchers had previously believed that vitamin B-12, when combined with folic acid (vitamin B-9) and vitamin B-6, might prevent diseases of the heart and blood vessels by reducing the levels of an amino acid in the blood (homocysteine). However, studies show that the combination of these vitamins doesn't seem to reduce the risk or severity of cardiovascular disease and stroke.
- Dementia. Vitamin B-12 deficiency is associated with dementia and low cognitive function, but it's not clear whether vitamin B-12 supplements might help prevent or treat dementia.
- Athletic performance. Unless you have a vitamin B-12 deficiency, there's no evidence that vitamin B-12 supplements will boost your energy or make you a better athlete.
Our take
Generally safe
Most people get enough vitamin B-12 from a balanced diet. However, older adults, vegetarians, vegans and people who have conditions that affect their ability to absorb vitamin B-12 from foods might benefit from the use of oral supplements.
Vitamin B-12 supplements also are recommended for women who are pregnant or breastfeeding exclusively and follow vegetarian or vegan diets.
Safety and side effects
When taken at appropriate doses, vitamin B-12 supplements are generally considered safe. While the recommended daily amount of vitamin B-12 for adults is 2.4 micrograms, higher doses have been found to be safe. Your body absorbs only as much as it needs, and any excess passes through your urine.
High doses of vitamin B-12, such as those used to treat a deficiency, might cause:
- Headache
- Nausea and vomiting
- Diarrhea
- Fatigue or weakness
- Tingling sensation in hands and feet
Interactions
Possible interactions include:
- Aminosalicylic acid (Paser). Taking this drug used to treat digestive problems might reduce your body's ability to absorb vitamin B-12.
- Colchicine (Colcrys, Mitigare, Gloperba). Taking this anti-inflammatory drug used to prevent and treat gout attacks might decrease your body's ability to absorb vitamin B-12.
- Metformin (Glumetza, Fortamet, others). Taking this diabetes drug might reduce your body's ability to absorb vitamin B-12.
- Proton pump inhibitors. Taking omeprazole (Prilosec), lansoprazole (Prevacid) or other stomach acid-reducing drugs might decrease your body's ability to absorb vitamin B-12.
- Vitamin C (ascorbic acid) supplements. Taking vitamin B-12 with vitamin C might reduce the available amount of vitamin B-12 in your body. To avoid this interaction, take vitamin C two or more hours after taking a vitamin B-12 supplement.
Your doctor might recommend changing drugs or timing doses to offset any potential interactions.
Sign up for free, and stay up to date on research advancements, health tips and current health topics, like COVID-19, plus expertise on managing health. To provide you with the most relevant and helpful information, and understand which information is beneficial, we may combine your email and website usage
information with other information we have about you. If you are a Mayo Clinic patient, this could include protected health information. If we combine this information with your protected health information, we will treat all of that information as protected health information and will only use or disclose that information as set forth in our notice of privacy practices. You may opt-out of email communications at any time by clicking on the unsubscribe link in the e-mail.From Mayo Clinic to your inbox
July 17, 2021
- Vitamin B12: Fact sheet for professionals. Office of Dietary Supplements. //ods.od.nih.gov/factsheets/VitaminB12-HealthProfessional. Accessed Jan. 9, 2021.
- Fairfield KM. Vitamin supplementation in disease prevention. //www.uptodate.com/contents/search. Accessed Jan. 9, 2021.
- Means RT Jr, et al. Causes and pathophysiology of vitamin B12 and folate deficiencies. //www.uptodate.com/contents/search. Accessed Jan. 9, 2021.
- Cyanocobalamin. IBM Micromedex. //www.micromedexsolutions.com. Accessed Jan. 9, 2021.
- Methylcobalamin. Facts & Comparisons eAnswers. //www.wolterskluwercdi.com/facts-comparisons-online/. Accessed Jan. 9, 2021.
- Vitamin B12. Natural Medicines. //naturalmedicines.therapeuticresearch.com. Accessed Jan. 9, 2021.
.