Table of ContentsView AllTable of ContentsHow It HelpsBenefits of SupplementsFood SourcesHow Much Is Needed?Symptoms of DeficiencyAt-Risk GroupsDo I Need to Supplement?
Table of ContentsView All
View All
Table of Contents
How It Helps
Benefits of Supplements
Food Sources
How Much Is Needed?
Symptoms of Deficiency
At-Risk Groups
Do I Need to Supplement?
Vitamin B12 is an essentialwater-soluble vitamin. The body doesn’t make vitamin B12, so it must be obtained through food. It can be found in meat, seafood, and dairy products. It is also added to certain foods like breakfast cereal.
Vitamin B12 contains the trace element cobalt, which is why it is sometimes mentioned ascobalamin,cyanocobalamin,hydroxycobalamin,methylcobalamin, or 5-deoxyadenosylcobalamin.
If you cannot get enough vitamin B12 through diet, you may need to take it in supplement form. Vitamin B12 supplements can help treat or prevent a deficiency in people who are at greater risk.
Supplementation is also often marketed to help prevent several conditions, such as heart disease, macular degeneration, and dementia. However, there is not enough research to support these uses.
This article reviews vitamin B12, why you need it, and who should supplement with it.
Getty Images / ljubaphoto
What Does Vitamin B12 Do?
Vitamin B12 has several primary functions in the human body, including:
Most people get enough vitamin B12 from the foods they eat, but some may require additional vitamin B12 through supplementation.
Benefits of Vitamin B12 Supplements
The following are potential health benefits of vitamin B12 supplementation.
Prevent or Treat Vitamin B12 Deficiency
Vitamin B12 deficiencyusually results from inadequate intake or poor absorption.
It can also occur due topernicious anemia, an autoimmune disorder that prevents the body from absorbing vitamin B12.
If you are concerned about your vitamin B12 status, discuss it with your healthcare provider. They can help order tests to check your status and prescribe supplementation.
Pregnancy Support
Multivitamin and mineral supplementation is frequently recommended during pregnancy.
Research has found thatmulti-micronutrient supplementationimproves maternal and child health outcomes, particularly in underdeveloped countries.
Vitamin B12 supplementation during pregnancy improves vitamin B12 status during and after pregnancy. Still, the clinical impact of this improvement in the long term and on the child’s health has not been studied.
Pregnant people who are at risk of vitamin B12 deficiency should discuss their diet and supplementation options with their primary care provider for pregnancy.
For example, if you follow a vegetarian diet, you may need to check your vitamin B12 status and supplement while pregnant or breastfeeding.
Unproven Uses
Vitamin B12 has been suggested to be beneficial in several areas. Yet, there is not enough research to support supplementation of vitamin B12 for these purposes.
Heart Health
Elevatedhomocysteine levelshave been associated with increased heart disease risk.While B vitamins may lower homocysteine levels, research has found no effect on reducing heart diseaseor cardiovascular events, including heart attack and stroke.
Macular Degeneration Risk
Like heart disease,age-related macular degeneration(AMD) is associated with elevated homocysteine levels and low levels of vitamin B12.AMD is an eye condition that affects an individual’s central vision.
However, no research has been conducted on the effects of vitamin B12 supplementation on AMD risk or the slowed progression of AMD.
Cognitive Function
Observational studies have suggested elevated homocysteine levels were associated with the incidence ofAlzheimer’s diseaseand dementia. Additionally, low vitamin B12 levels have been associated with cognitive impairment (confusion or trouble with memory and thinking).
However, further research has not found a role for vitamin B12 deficiency and supplementation for cognitive impairment.
Clinical trials evaluating supplementation of vitamin B12 and other B vitamins had little effect on preventing cognitive decline in healthy individuals.
Supplementing vitamin B12 also had no impact on reducing the risk or slowing the progression of dementia or Alzheimer’s in older adults.
Mood
Some research has suggested that low intake of B vitamins may be related to a higher risk ofdepressionin females.
One systematic review found that supplementation with B vitamins and vitamin D may improve the symptoms associated with depression and anxiety.
However, further research on clinical trials found that vitamin B12 supplementation alone had no effect on reducing depressive symptoms or improving cognitive function.
Energy and Athletic Performance
Vitamin B12 and other B vitamins are often touted as energy and performance enhancers for athletes.
However, the research does not support this. In one study, there was no difference in the bench press and leg press lifting volume or sprint performance in those taking a supplement that included vitamin B12,folate (vitamin B9), and several other nutrients compared to a placebo (an ineffective substance given to people in a drug trial control group).
Vitamin B12 does not appear to have any beneficial effect on performance in the absence of a deficiency.
B Vitamins: What Are Their Health Benefits?
Food Sources of Vitamin B12
Good food sources of vitamin B12often include meat and seafood. Beef liver, ground beef, and turkey are notable meats that contain a lot of vitamin B12.
If you prefer seafood, you can easily get your daily vitamin B12 requirements with 3 ounces of clams, oysters, salmon, or tuna.
Dairy products like milk, yogurt, and cheese also provide good amounts of vitamin B12. Eggs are another protein food that provides vitamin B12.
Some breakfast cereals are fortified with vitamins and minerals, including vitamin B12. Read the nutrition facts label to see if vitamin B12 has been added.
For vegetarians,nutritional yeastis an excellent source of vitamin B12.
How Much Vitamin B12 Do I Need?
There is a Recommended Dietary Allowance (RDA) set for vitamin B12 intake. The amounts vary depending on age:
Vitamin B12 requirements increase to 2.6 mg and 2.8 mg daily during pregnancy and lactation, respectively.
Signs and Symptoms of Vitamin B12 Deficiency
Vitamin B12 deficiency can occur due to the following:
The body stores up to 5 milligrams (mg) of vitamin B12, so symptoms of a deficiency take several months to years to develop. Signs of a possible deficiency include:
Who Is at Risk of Vitamin B12 Deficiency?
Deficiency of vitamin B12 is typically the result of too little intake of vitamin B12-rich foods or altered/poor absorption. The following populations are at a heightened risk of vitamin B12 deficiency:
Do I Need to Take Supplements?
Based on the available evidence, only people with an existing deficiency or risk of developing a deficiency should take vitamin B12 supplements. This may include:
Otherwise, you should be able to get enough vitamin B12 through diet alone.
Before purchasing vitamin B12 supplements, discuss with your healthcare provider whether you actually need supplementation. They can help you determine whether supplements are the right choice for you, what form of supplements would be best, and recommend a proper dose.
Additionally, many supplements may interact with medications. Before starting your supplements, talk to your provider about what medications you are taking. This includes over-the-counter and prescription medications, as well as other supplements.
How to Choose a SupplementDietary supplements are not regulated like drugs in the United States. They can cause interactions with medications or have other safety concerns. For this reason, it’s important to be aware of what to look for whenchoosing a supplement, such as independent testing, potential drug interactions, and more.
How to Choose a Supplement
Dietary supplements are not regulated like drugs in the United States. They can cause interactions with medications or have other safety concerns. For this reason, it’s important to be aware of what to look for whenchoosing a supplement, such as independent testing, potential drug interactions, and more.
Summary
Vitamin B12 is an essential vitamin that we get from our diet. Most people can easily get enough vitamin B12 from the food they eat. However, there are a few groups of people who either don’t get enough in their diet or have trouble properly absorbing vitamin B12. In these cases, they may benefit from supplementation.
Vitamin B12 supplementation is marketed for several other reasons, including heart health, eye health, cognitive decline, mood enhancement, and more. However, insufficient evidence exists to routinely supplement vitamin B12 for these conditions.
As always, discuss nutritional supplementation with your primary care provider to ensure that it is appropriate for you.
14 SourcesVerywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.National Institute of Health. Office of Dietary Supplements.Vitamin B12. March 26, 2024.Keats EC, Oh C, Chau T, et al.Effects of vitamin and mineral supplementation during pregnancy on maternal, birth, child health and development outcomes in low- and middle-income countries: a systematic review.Campbell Syst Rev. 2021;17(2):e1127. doi:10.1002/cl2.1127Finkelstein JL, Fothergill A, Venkatramanan S, et al.Vitamin B12 supplementation during pregnancy for maternal and child health outcomes.Cochrane Database Syst Rev. 2024;1(1):CD013823. doi:10.1002/14651858.CD013823.pub2Rashid S, Meier V, Patrick H.Review of vitamin B12 deficiency in pregnancy: a diagnosis not to miss as veganism and vegetarianism become more prevalent.Eur J Haematol. 2021;106(4):450-455. doi:10.1111/ejh.13571Martí-Carvajal AJ, Solà I, et al.Homocysteine-lowering interventions for preventing cardiovascular events.Cochrane Database Syst Rev. 2017;8(8):CD006612. doi:10.1002/14651858.CD006612.pub5Huang P, Wang F, Sah BK, et al.Homocysteine and the risk of age-related macular degeneration: a systematic review and meta-analysis.Sci Rep. 2015;5:10585. doi:10.1038/srep10585National Institutes of Health. National Eye Institute.Age-related macular degeneration (AMD).O’Leary F, Allman-Farinelli M, Samman S.Vitamin B₁₂ status, cognitive decline and dementia: a systematic review of prospective cohort studies.Br J Nutr. 2012;108(11):1948-1961. doi:10.1017/S0007114512004175Rutjes AW, Denton DA, Di Nisio M, et al.Vitamin and mineral supplementation for maintaining cognitive function in cognitively healthy people in mid and late life.Cochrane Database Syst Rev. 2018;12(12):CD011906. Published 2018 Dec 17. doi:10.1002/14651858.CD011906.pub2McCleery J, Abraham RP, Denton DA, et al.Vitamin and mineral supplementation for preventing dementia or delaying cognitive decline in people with mild cognitive impairment.Cochrane Database Syst Rev. 2018;11(11):CD011905. Published 2018 Nov 1. doi:10.1002/14651858.CD011905.pub2Wu Y, Zhang L, Li S, Zhang D.Associations of dietary vitamin B1, vitamin B2, vitamin B6, and vitamin B12 with the risk of depression: a systematic review and meta-analysis.Nutr Rev. 2022;80(3):351-366. doi:10.1093/nutrit/nuab014Borges-Vieira JG, Cardoso CKS.Efficacy of B-vitamins and vitamin D therapy in improving depressive and anxiety disorders: a systematic review of randomized controlled trials.Nutr Neurosci. 2023;26(3):187-207. doi:10.1080/1028415X.2022.2031494Markun S, Gravestock I, Jäger L, Rosemann T, Pichierri G, Burgstaller JM.Effects of Vitamin B12 Supplementation on Cognitive Function, Depressive Symptoms, and Fatigue: A Systematic Review, Meta-Analysis, and Meta-Regression.Nutrients. 2021;13(3):923. Published 2021 Mar 12. doi:10.3390/nu13030923Jung YP, Earnest CP, Koozehchian M, et al.Effects of acute ingestion of a pre-workout dietary supplement with and withoutp-synephrine on resting energy expenditure, cognitive function and exercise performance.J Int Soc Sports Nutr. 2017;14:3. Published 2017 Jan 12. doi:10.1186/s12970-016-0159-2
14 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.National Institute of Health. Office of Dietary Supplements.Vitamin B12. March 26, 2024.Keats EC, Oh C, Chau T, et al.Effects of vitamin and mineral supplementation during pregnancy on maternal, birth, child health and development outcomes in low- and middle-income countries: a systematic review.Campbell Syst Rev. 2021;17(2):e1127. doi:10.1002/cl2.1127Finkelstein JL, Fothergill A, Venkatramanan S, et al.Vitamin B12 supplementation during pregnancy for maternal and child health outcomes.Cochrane Database Syst Rev. 2024;1(1):CD013823. doi:10.1002/14651858.CD013823.pub2Rashid S, Meier V, Patrick H.Review of vitamin B12 deficiency in pregnancy: a diagnosis not to miss as veganism and vegetarianism become more prevalent.Eur J Haematol. 2021;106(4):450-455. doi:10.1111/ejh.13571Martí-Carvajal AJ, Solà I, et al.Homocysteine-lowering interventions for preventing cardiovascular events.Cochrane Database Syst Rev. 2017;8(8):CD006612. doi:10.1002/14651858.CD006612.pub5Huang P, Wang F, Sah BK, et al.Homocysteine and the risk of age-related macular degeneration: a systematic review and meta-analysis.Sci Rep. 2015;5:10585. doi:10.1038/srep10585National Institutes of Health. National Eye Institute.Age-related macular degeneration (AMD).O’Leary F, Allman-Farinelli M, Samman S.Vitamin B₁₂ status, cognitive decline and dementia: a systematic review of prospective cohort studies.Br J Nutr. 2012;108(11):1948-1961. doi:10.1017/S0007114512004175Rutjes AW, Denton DA, Di Nisio M, et al.Vitamin and mineral supplementation for maintaining cognitive function in cognitively healthy people in mid and late life.Cochrane Database Syst Rev. 2018;12(12):CD011906. Published 2018 Dec 17. doi:10.1002/14651858.CD011906.pub2McCleery J, Abraham RP, Denton DA, et al.Vitamin and mineral supplementation for preventing dementia or delaying cognitive decline in people with mild cognitive impairment.Cochrane Database Syst Rev. 2018;11(11):CD011905. Published 2018 Nov 1. doi:10.1002/14651858.CD011905.pub2Wu Y, Zhang L, Li S, Zhang D.Associations of dietary vitamin B1, vitamin B2, vitamin B6, and vitamin B12 with the risk of depression: a systematic review and meta-analysis.Nutr Rev. 2022;80(3):351-366. doi:10.1093/nutrit/nuab014Borges-Vieira JG, Cardoso CKS.Efficacy of B-vitamins and vitamin D therapy in improving depressive and anxiety disorders: a systematic review of randomized controlled trials.Nutr Neurosci. 2023;26(3):187-207. doi:10.1080/1028415X.2022.2031494Markun S, Gravestock I, Jäger L, Rosemann T, Pichierri G, Burgstaller JM.Effects of Vitamin B12 Supplementation on Cognitive Function, Depressive Symptoms, and Fatigue: A Systematic Review, Meta-Analysis, and Meta-Regression.Nutrients. 2021;13(3):923. Published 2021 Mar 12. doi:10.3390/nu13030923Jung YP, Earnest CP, Koozehchian M, et al.Effects of acute ingestion of a pre-workout dietary supplement with and withoutp-synephrine on resting energy expenditure, cognitive function and exercise performance.J Int Soc Sports Nutr. 2017;14:3. Published 2017 Jan 12. doi:10.1186/s12970-016-0159-2
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
National Institute of Health. Office of Dietary Supplements.Vitamin B12. March 26, 2024.Keats EC, Oh C, Chau T, et al.Effects of vitamin and mineral supplementation during pregnancy on maternal, birth, child health and development outcomes in low- and middle-income countries: a systematic review.Campbell Syst Rev. 2021;17(2):e1127. doi:10.1002/cl2.1127Finkelstein JL, Fothergill A, Venkatramanan S, et al.Vitamin B12 supplementation during pregnancy for maternal and child health outcomes.Cochrane Database Syst Rev. 2024;1(1):CD013823. doi:10.1002/14651858.CD013823.pub2Rashid S, Meier V, Patrick H.Review of vitamin B12 deficiency in pregnancy: a diagnosis not to miss as veganism and vegetarianism become more prevalent.Eur J Haematol. 2021;106(4):450-455. doi:10.1111/ejh.13571Martí-Carvajal AJ, Solà I, et al.Homocysteine-lowering interventions for preventing cardiovascular events.Cochrane Database Syst Rev. 2017;8(8):CD006612. doi:10.1002/14651858.CD006612.pub5Huang P, Wang F, Sah BK, et al.Homocysteine and the risk of age-related macular degeneration: a systematic review and meta-analysis.Sci Rep. 2015;5:10585. doi:10.1038/srep10585National Institutes of Health. National Eye Institute.Age-related macular degeneration (AMD).O’Leary F, Allman-Farinelli M, Samman S.Vitamin B₁₂ status, cognitive decline and dementia: a systematic review of prospective cohort studies.Br J Nutr. 2012;108(11):1948-1961. doi:10.1017/S0007114512004175Rutjes AW, Denton DA, Di Nisio M, et al.Vitamin and mineral supplementation for maintaining cognitive function in cognitively healthy people in mid and late life.Cochrane Database Syst Rev. 2018;12(12):CD011906. Published 2018 Dec 17. doi:10.1002/14651858.CD011906.pub2McCleery J, Abraham RP, Denton DA, et al.Vitamin and mineral supplementation for preventing dementia or delaying cognitive decline in people with mild cognitive impairment.Cochrane Database Syst Rev. 2018;11(11):CD011905. Published 2018 Nov 1. doi:10.1002/14651858.CD011905.pub2Wu Y, Zhang L, Li S, Zhang D.Associations of dietary vitamin B1, vitamin B2, vitamin B6, and vitamin B12 with the risk of depression: a systematic review and meta-analysis.Nutr Rev. 2022;80(3):351-366. doi:10.1093/nutrit/nuab014Borges-Vieira JG, Cardoso CKS.Efficacy of B-vitamins and vitamin D therapy in improving depressive and anxiety disorders: a systematic review of randomized controlled trials.Nutr Neurosci. 2023;26(3):187-207. doi:10.1080/1028415X.2022.2031494Markun S, Gravestock I, Jäger L, Rosemann T, Pichierri G, Burgstaller JM.Effects of Vitamin B12 Supplementation on Cognitive Function, Depressive Symptoms, and Fatigue: A Systematic Review, Meta-Analysis, and Meta-Regression.Nutrients. 2021;13(3):923. Published 2021 Mar 12. doi:10.3390/nu13030923Jung YP, Earnest CP, Koozehchian M, et al.Effects of acute ingestion of a pre-workout dietary supplement with and withoutp-synephrine on resting energy expenditure, cognitive function and exercise performance.J Int Soc Sports Nutr. 2017;14:3. Published 2017 Jan 12. doi:10.1186/s12970-016-0159-2
National Institute of Health. Office of Dietary Supplements.Vitamin B12. March 26, 2024.
Keats EC, Oh C, Chau T, et al.Effects of vitamin and mineral supplementation during pregnancy on maternal, birth, child health and development outcomes in low- and middle-income countries: a systematic review.Campbell Syst Rev. 2021;17(2):e1127. doi:10.1002/cl2.1127
Finkelstein JL, Fothergill A, Venkatramanan S, et al.Vitamin B12 supplementation during pregnancy for maternal and child health outcomes.Cochrane Database Syst Rev. 2024;1(1):CD013823. doi:10.1002/14651858.CD013823.pub2
Rashid S, Meier V, Patrick H.Review of vitamin B12 deficiency in pregnancy: a diagnosis not to miss as veganism and vegetarianism become more prevalent.Eur J Haematol. 2021;106(4):450-455. doi:10.1111/ejh.13571
Martí-Carvajal AJ, Solà I, et al.Homocysteine-lowering interventions for preventing cardiovascular events.Cochrane Database Syst Rev. 2017;8(8):CD006612. doi:10.1002/14651858.CD006612.pub5
Huang P, Wang F, Sah BK, et al.Homocysteine and the risk of age-related macular degeneration: a systematic review and meta-analysis.Sci Rep. 2015;5:10585. doi:10.1038/srep10585
National Institutes of Health. National Eye Institute.Age-related macular degeneration (AMD).
O’Leary F, Allman-Farinelli M, Samman S.Vitamin B₁₂ status, cognitive decline and dementia: a systematic review of prospective cohort studies.Br J Nutr. 2012;108(11):1948-1961. doi:10.1017/S0007114512004175
Rutjes AW, Denton DA, Di Nisio M, et al.Vitamin and mineral supplementation for maintaining cognitive function in cognitively healthy people in mid and late life.Cochrane Database Syst Rev. 2018;12(12):CD011906. Published 2018 Dec 17. doi:10.1002/14651858.CD011906.pub2
McCleery J, Abraham RP, Denton DA, et al.Vitamin and mineral supplementation for preventing dementia or delaying cognitive decline in people with mild cognitive impairment.Cochrane Database Syst Rev. 2018;11(11):CD011905. Published 2018 Nov 1. doi:10.1002/14651858.CD011905.pub2
Wu Y, Zhang L, Li S, Zhang D.Associations of dietary vitamin B1, vitamin B2, vitamin B6, and vitamin B12 with the risk of depression: a systematic review and meta-analysis.Nutr Rev. 2022;80(3):351-366. doi:10.1093/nutrit/nuab014
Borges-Vieira JG, Cardoso CKS.Efficacy of B-vitamins and vitamin D therapy in improving depressive and anxiety disorders: a systematic review of randomized controlled trials.Nutr Neurosci. 2023;26(3):187-207. doi:10.1080/1028415X.2022.2031494
Markun S, Gravestock I, Jäger L, Rosemann T, Pichierri G, Burgstaller JM.Effects of Vitamin B12 Supplementation on Cognitive Function, Depressive Symptoms, and Fatigue: A Systematic Review, Meta-Analysis, and Meta-Regression.Nutrients. 2021;13(3):923. Published 2021 Mar 12. doi:10.3390/nu13030923
Jung YP, Earnest CP, Koozehchian M, et al.Effects of acute ingestion of a pre-workout dietary supplement with and withoutp-synephrine on resting energy expenditure, cognitive function and exercise performance.J Int Soc Sports Nutr. 2017;14:3. Published 2017 Jan 12. doi:10.1186/s12970-016-0159-2
Meet Our Medical Expert Board
Share Feedback
Was this page helpful?Thanks for your feedback!What is your feedback?OtherHelpfulReport an ErrorSubmit
Was this page helpful?
Thanks for your feedback!
What is your feedback?OtherHelpfulReport an ErrorSubmit
What is your feedback?
