Table of ContentsView AllTable of ContentsBenefitsHow Much Is Too Much?Side EffectsHigh LevelsLow LevelsPregnancy and Vitamin B12
Table of ContentsView All
View All
Table of Contents
Benefits
How Much Is Too Much?
Side Effects
High Levels
Low Levels
Pregnancy and Vitamin B12
Having too much vitamin B12 is nearly impossible because any excess of this water-soluble nutrient washes out of the body before it poses any harm.For this reason, the U.S. Food and Drug Administration (FDA) listsvitamin B12in the Generally Regarded as Safe (GRAS) category and has not set an upper dosage limit.
In the United States, the Food and Drug Administration (FDA) does not regulate supplements the way it regulates prescription drugs. That means some supplement products may not contain what the label says. Whenchoosing a supplement, look for independently tested products and consult a healthcare provider, registered dietitian nutritionist (RD or RDN), or pharmacist.
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Vitamin B12 Benefits
There are several benefits associated with B12, whether through diet or supplementation. They include:
How Much B12 Should You Be Getting Each Day?To reap the benefits of B12 within the body, you’ll have to get enough of the essential nutrient. The amount of B12 a person needs depends on their age or pregnancy status and can be broken down as follows:Children 1–3:0.9 microgram (mcg)/dayChildren 4–8:1.2 mcg/dayChildren 9–13:1.8 mcg/dayTeens 14–18:2.4 mcg/dayAdults:2.4 mcg/dayPregnant people:2.6 mcg/dayPeople who are breastfeeding:2.8 mcg/day
How Much B12 Should You Be Getting Each Day?
To reap the benefits of B12 within the body, you’ll have to get enough of the essential nutrient. The amount of B12 a person needs depends on their age or pregnancy status and can be broken down as follows:Children 1–3:0.9 microgram (mcg)/dayChildren 4–8:1.2 mcg/dayChildren 9–13:1.8 mcg/dayTeens 14–18:2.4 mcg/dayAdults:2.4 mcg/dayPregnant people:2.6 mcg/dayPeople who are breastfeeding:2.8 mcg/day
To reap the benefits of B12 within the body, you’ll have to get enough of the essential nutrient. The amount of B12 a person needs depends on their age or pregnancy status and can be broken down as follows:
Fat-Soluble vs. Water-Soluble Vitamins
How Much B12 Is Too Much?
When looking at vitamin B12 levels, it’s hard to say how much is too much. The vitamin is water-soluble, meaning it’s generally safe at high levels because the body flushes out what it doesn’t use with water.
While there is a general recommendation, some people may need more than others based on several factors, including:
People in the above-mentioned groups may need more than the daily recommended allowance, but those in the general population do not, and taking more vitamin B12 than you need is unnecessary.
Many studies have investigated high doses of B12 to see how it affects the body, and none has determined a specific amount that could lead to an overdose.
Taking B12 in ExcessWhile no known adverse health effects are associated with taking too much B12, you’re wasting money if you supplement with the vitamin when you don’t need to. Your body will use what it needs and then expel the rest.
Taking B12 in Excess
While no known adverse health effects are associated with taking too much B12, you’re wasting money if you supplement with the vitamin when you don’t need to. Your body will use what it needs and then expel the rest.
Can Too Much B12 Cause Side Effects?
Since taking B12 in high doses has not been seen to negatively affect people in any way, there are no known symptoms associated with too-high levels of the vitamin.
As mentioned above, the water-soluble vitamin is expelled from the body before it has the chance to cause any issues.
What Is Vitamin Toxicity?
Can People Have High Vitamin B12 Blood Levels?
Excess levels of vitamin B12 in the blood are highly uncommon as it leaves the body through urine when it is not needed. That said, people can see an increase in their B12 levels in the blood if they have certain conditions, such as:
These conditions often present with elevated B12, but the levels don’t seem to be so high that they cause toxicity to occur.
What If You Have Low B12 Levels?
Vitamin B12 deficiencies can be detrimental to one’s overall health. Some of the effects of low levels of vitamin B12 include:
Over time, vitamin B12 deficiencies can increase the risk of various health disorders, including:
Foods With Vitamin B12To increase the amount of B12 in your diet, you can add in foods such as:Beef liverClamsNutritional yeastSalmonTuneBeefMilkPlain fat-free yogurtFortified breakfast cerealsEggsCheddar cheeseTempeh
Foods With Vitamin B12
To increase the amount of B12 in your diet, you can add in foods such as:Beef liverClamsNutritional yeastSalmonTuneBeefMilkPlain fat-free yogurtFortified breakfast cerealsEggsCheddar cheeseTempeh
To increase the amount of B12 in your diet, you can add in foods such as:
The Best Sources of Vitamin B12 for Any Diet
People who are pregnant often need more vitamin B12 than those who are not because it helps with fetal development. Deficiencies in vitamin B12 also increase the risk of birth defects, so getting enough is vital.Pregnant people should aim to get at least 2.6 mcg/day to ensure that they and the fetus are getting enough of this essential nutrient during pregnancy.
The 8 Best B12 Supplements, According to a Dietitian
Summary
Vitamin B12 is an essential nutrient vital for many bodily processes. Without enough, people may experience a deficiency that can be so severe it could lead to adverse health complications, such as anemia, depression, and an increased risk for certain cancers. Because of that, knowing how much you should be getting per day is vital to ensure your needs are met.
There is no clinical evidence of side effects from taking too much. The vitamin is water soluble, so anything the body doesn’t use is expelled through the urine. This means it cannot build up within the body to dangerous levels. Taking more than the recommended amount may not lead to severe health consequences, but it is unnecessary unless a healthcare provider tells you otherwise.
17 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 Institutes of Health.Vitamin B12 - Fact Sheet for Health Professionals. Updated March 26, 2021.U.S. Food and Drug Administration.GRAS Substances (SCOGS) Database-Vitamin B12. Updated June 25, 2019.Office of Dietary Supplements.Vitamin B12.Behere RV, Deshmukh AS, Otiv S, Gupte MD, Yajnik CS.Maternal vitamin B12 status during pregnancy and its association with outcomes of pregnancy and health of the offspring: A systematic review and implications for policy in India.Front Endocrinol (Lausanne).2021 Apr 12;12:619176. doi:10.3389/fendo.2021.619176Macêdo LLG, Carvalho CMRG, Cavalcanti JC, Freitas BJESA.Vitamin B12, bone mineral density and fracture risk in adults: A systematic review.Rev Assoc Med Bras (1992).2017 Sep;63(9):801-809. doi:10.1590/1806-9282.63.09.801Merle BMJ, Barthes S, Féart C, Cougnard-Grégoire A, Korobelnik JF, Rougier MB, Delyfer MN, Delcourt C.B vitamins and incidence of advanced age-related macular degeneration: The alienor study.Nutrients.2022 Jul 8;14(14):2821. doi:10.3390/nu14142821Sangle P, Sandhu O, Aftab Z, Anthony AT, Khan S.Vitamin B12 supplementation: Preventing onset and improving prognosis of depression.Cureus.2020 Oct 26;12(10):e11169. doi:10.7759/cureus.11169Tardy AL, Pouteau E, Marquez D, Yilmaz C, Scholey A.Vitamins and minerals for energy, fatigue and cognition: A narrative review of the biochemical and clinical evidence.Nutrients.2020 Jan 16;12(1):228. doi:10.3390/nu12010228Tayebi A, Biniaz V, Savari S, Ebadi A, Shermeh MS, Einollahi B, Rahimi A.Effect of Vitamin B12 supplementation on serum homocysteine in patients undergoing hemodialysis: A randomized controlled trial.Saudi J Kidney Dis Transpl.2016 Mar;27(2):256-62. doi:10.4103/1319-2442.178255DiBaise M, Tarleton SM.Hair, nails, and skin: Differentiating cutaneous manifestations of micronutrient deficiency.Nutr Clin Pract.2019 Aug;34(4):490-503. doi:10.1002/ncp.10321National Institutes of Health Office of Dietary Supplements.Vitamin B12 fact sheet for consumers.Mount Sinai.Vitamin B12 level.Johns Hopkins Medicine.Vitamin B12 deficiency anemia.UK National Health Service.Vitamin B12 or folate deficiency complications.Harvard Health Publishing Harvard Medical School.Vitamin B12 deficiency can be sneaky and harmful.National Institutes of Health Office of Dietary Supplements.Vitamin B12 fact sheet for health professionals.Chandyo RK, Kvestad I, Ulak M, Ranjitkar S, Hysing M, Shrestha M, Schwinger C, McCann A, Ueland PM, Basnet S, Shrestha L, Strand TA.The effect of vitamin B12 supplementation during pregnancy on infant growth and development in Nepal: a community-based, double-blind, randomised, placebo-controlled trial.Lancet.2023 May 6;401(10387):1508-1517. doi:10.1016/S0140-6736(23)00346-X
17 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 Institutes of Health.Vitamin B12 - Fact Sheet for Health Professionals. Updated March 26, 2021.U.S. Food and Drug Administration.GRAS Substances (SCOGS) Database-Vitamin B12. Updated June 25, 2019.Office of Dietary Supplements.Vitamin B12.Behere RV, Deshmukh AS, Otiv S, Gupte MD, Yajnik CS.Maternal vitamin B12 status during pregnancy and its association with outcomes of pregnancy and health of the offspring: A systematic review and implications for policy in India.Front Endocrinol (Lausanne).2021 Apr 12;12:619176. doi:10.3389/fendo.2021.619176Macêdo LLG, Carvalho CMRG, Cavalcanti JC, Freitas BJESA.Vitamin B12, bone mineral density and fracture risk in adults: A systematic review.Rev Assoc Med Bras (1992).2017 Sep;63(9):801-809. doi:10.1590/1806-9282.63.09.801Merle BMJ, Barthes S, Féart C, Cougnard-Grégoire A, Korobelnik JF, Rougier MB, Delyfer MN, Delcourt C.B vitamins and incidence of advanced age-related macular degeneration: The alienor study.Nutrients.2022 Jul 8;14(14):2821. doi:10.3390/nu14142821Sangle P, Sandhu O, Aftab Z, Anthony AT, Khan S.Vitamin B12 supplementation: Preventing onset and improving prognosis of depression.Cureus.2020 Oct 26;12(10):e11169. doi:10.7759/cureus.11169Tardy AL, Pouteau E, Marquez D, Yilmaz C, Scholey A.Vitamins and minerals for energy, fatigue and cognition: A narrative review of the biochemical and clinical evidence.Nutrients.2020 Jan 16;12(1):228. doi:10.3390/nu12010228Tayebi A, Biniaz V, Savari S, Ebadi A, Shermeh MS, Einollahi B, Rahimi A.Effect of Vitamin B12 supplementation on serum homocysteine in patients undergoing hemodialysis: A randomized controlled trial.Saudi J Kidney Dis Transpl.2016 Mar;27(2):256-62. doi:10.4103/1319-2442.178255DiBaise M, Tarleton SM.Hair, nails, and skin: Differentiating cutaneous manifestations of micronutrient deficiency.Nutr Clin Pract.2019 Aug;34(4):490-503. doi:10.1002/ncp.10321National Institutes of Health Office of Dietary Supplements.Vitamin B12 fact sheet for consumers.Mount Sinai.Vitamin B12 level.Johns Hopkins Medicine.Vitamin B12 deficiency anemia.UK National Health Service.Vitamin B12 or folate deficiency complications.Harvard Health Publishing Harvard Medical School.Vitamin B12 deficiency can be sneaky and harmful.National Institutes of Health Office of Dietary Supplements.Vitamin B12 fact sheet for health professionals.Chandyo RK, Kvestad I, Ulak M, Ranjitkar S, Hysing M, Shrestha M, Schwinger C, McCann A, Ueland PM, Basnet S, Shrestha L, Strand TA.The effect of vitamin B12 supplementation during pregnancy on infant growth and development in Nepal: a community-based, double-blind, randomised, placebo-controlled trial.Lancet.2023 May 6;401(10387):1508-1517. doi:10.1016/S0140-6736(23)00346-X
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 Institutes of Health.Vitamin B12 - Fact Sheet for Health Professionals. Updated March 26, 2021.U.S. Food and Drug Administration.GRAS Substances (SCOGS) Database-Vitamin B12. Updated June 25, 2019.Office of Dietary Supplements.Vitamin B12.Behere RV, Deshmukh AS, Otiv S, Gupte MD, Yajnik CS.Maternal vitamin B12 status during pregnancy and its association with outcomes of pregnancy and health of the offspring: A systematic review and implications for policy in India.Front Endocrinol (Lausanne).2021 Apr 12;12:619176. doi:10.3389/fendo.2021.619176Macêdo LLG, Carvalho CMRG, Cavalcanti JC, Freitas BJESA.Vitamin B12, bone mineral density and fracture risk in adults: A systematic review.Rev Assoc Med Bras (1992).2017 Sep;63(9):801-809. doi:10.1590/1806-9282.63.09.801Merle BMJ, Barthes S, Féart C, Cougnard-Grégoire A, Korobelnik JF, Rougier MB, Delyfer MN, Delcourt C.B vitamins and incidence of advanced age-related macular degeneration: The alienor study.Nutrients.2022 Jul 8;14(14):2821. doi:10.3390/nu14142821Sangle P, Sandhu O, Aftab Z, Anthony AT, Khan S.Vitamin B12 supplementation: Preventing onset and improving prognosis of depression.Cureus.2020 Oct 26;12(10):e11169. doi:10.7759/cureus.11169Tardy AL, Pouteau E, Marquez D, Yilmaz C, Scholey A.Vitamins and minerals for energy, fatigue and cognition: A narrative review of the biochemical and clinical evidence.Nutrients.2020 Jan 16;12(1):228. doi:10.3390/nu12010228Tayebi A, Biniaz V, Savari S, Ebadi A, Shermeh MS, Einollahi B, Rahimi A.Effect of Vitamin B12 supplementation on serum homocysteine in patients undergoing hemodialysis: A randomized controlled trial.Saudi J Kidney Dis Transpl.2016 Mar;27(2):256-62. doi:10.4103/1319-2442.178255DiBaise M, Tarleton SM.Hair, nails, and skin: Differentiating cutaneous manifestations of micronutrient deficiency.Nutr Clin Pract.2019 Aug;34(4):490-503. doi:10.1002/ncp.10321National Institutes of Health Office of Dietary Supplements.Vitamin B12 fact sheet for consumers.Mount Sinai.Vitamin B12 level.Johns Hopkins Medicine.Vitamin B12 deficiency anemia.UK National Health Service.Vitamin B12 or folate deficiency complications.Harvard Health Publishing Harvard Medical School.Vitamin B12 deficiency can be sneaky and harmful.National Institutes of Health Office of Dietary Supplements.Vitamin B12 fact sheet for health professionals.Chandyo RK, Kvestad I, Ulak M, Ranjitkar S, Hysing M, Shrestha M, Schwinger C, McCann A, Ueland PM, Basnet S, Shrestha L, Strand TA.The effect of vitamin B12 supplementation during pregnancy on infant growth and development in Nepal: a community-based, double-blind, randomised, placebo-controlled trial.Lancet.2023 May 6;401(10387):1508-1517. doi:10.1016/S0140-6736(23)00346-X
National Institutes of Health.Vitamin B12 - Fact Sheet for Health Professionals. Updated March 26, 2021.
U.S. Food and Drug Administration.GRAS Substances (SCOGS) Database-Vitamin B12. Updated June 25, 2019.
Office of Dietary Supplements.Vitamin B12.
Behere RV, Deshmukh AS, Otiv S, Gupte MD, Yajnik CS.Maternal vitamin B12 status during pregnancy and its association with outcomes of pregnancy and health of the offspring: A systematic review and implications for policy in India.Front Endocrinol (Lausanne).2021 Apr 12;12:619176. doi:10.3389/fendo.2021.619176
Macêdo LLG, Carvalho CMRG, Cavalcanti JC, Freitas BJESA.Vitamin B12, bone mineral density and fracture risk in adults: A systematic review.Rev Assoc Med Bras (1992).2017 Sep;63(9):801-809. doi:10.1590/1806-9282.63.09.801
Merle BMJ, Barthes S, Féart C, Cougnard-Grégoire A, Korobelnik JF, Rougier MB, Delyfer MN, Delcourt C.B vitamins and incidence of advanced age-related macular degeneration: The alienor study.Nutrients.2022 Jul 8;14(14):2821. doi:10.3390/nu14142821
Sangle P, Sandhu O, Aftab Z, Anthony AT, Khan S.Vitamin B12 supplementation: Preventing onset and improving prognosis of depression.Cureus.2020 Oct 26;12(10):e11169. doi:10.7759/cureus.11169
Tardy AL, Pouteau E, Marquez D, Yilmaz C, Scholey A.Vitamins and minerals for energy, fatigue and cognition: A narrative review of the biochemical and clinical evidence.Nutrients.2020 Jan 16;12(1):228. doi:10.3390/nu12010228
Tayebi A, Biniaz V, Savari S, Ebadi A, Shermeh MS, Einollahi B, Rahimi A.Effect of Vitamin B12 supplementation on serum homocysteine in patients undergoing hemodialysis: A randomized controlled trial.Saudi J Kidney Dis Transpl.2016 Mar;27(2):256-62. doi:10.4103/1319-2442.178255
DiBaise M, Tarleton SM.Hair, nails, and skin: Differentiating cutaneous manifestations of micronutrient deficiency.Nutr Clin Pract.2019 Aug;34(4):490-503. doi:10.1002/ncp.10321
National Institutes of Health Office of Dietary Supplements.Vitamin B12 fact sheet for consumers.
Mount Sinai.Vitamin B12 level.
Johns Hopkins Medicine.Vitamin B12 deficiency anemia.
UK National Health Service.Vitamin B12 or folate deficiency complications.
Harvard Health Publishing Harvard Medical School.Vitamin B12 deficiency can be sneaky and harmful.
National Institutes of Health Office of Dietary Supplements.Vitamin B12 fact sheet for health professionals.
Chandyo RK, Kvestad I, Ulak M, Ranjitkar S, Hysing M, Shrestha M, Schwinger C, McCann A, Ueland PM, Basnet S, Shrestha L, Strand TA.The effect of vitamin B12 supplementation during pregnancy on infant growth and development in Nepal: a community-based, double-blind, randomised, placebo-controlled trial.Lancet.2023 May 6;401(10387):1508-1517. doi:10.1016/S0140-6736(23)00346-X
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