In This ArticleView AllIn This ArticleWhat Is Vitamin B12?How Much Do You Need?Do You Need a Supplement?Can You Take Too Much?Excess Vitamin B12FAQs
In This ArticleView All
View All
In This Article
What Is Vitamin B12?
How Much Do You Need?
Do You Need a Supplement?
Can You Take Too Much?
Excess Vitamin B12
FAQs
Close
Photo:Viktoriya Kraynyuk/Getty Images
Viktoriya Kraynyuk/Getty Images
Vitamins and minerals are essential for vitality, which may explain why vitamin supplements are a multibillion-dollar business.,Among the plethora of supplements on the market, vitamin B12 ranks near the top of the popularity list. In fact, roughly a quarter of men and nearly a third of women take B12 in supplement form, according to the National Institutes of Health.Thismember of the B vitamin familyis vital for red blood cell production, nerve and brain function, and cellular health. It’s also touted for its ability to help boost energy and mood.
Buthow much B12 do you need, and can you take too much of it? (Or do you even need to take it at all?) Most people get adequate amounts of B12 through food. However, a B12 supplement can help ensure you’re getting enough—especially if you’re vegan or vegetarian or if you struggle to absorb this essential nutrient.
Read on to learn who can benefit from a B12 supplement and if it’s possible to take too much of it.
Vitamin B12 (also called cobalamin) is a water-soluble vitamin that’s crucial for various bodily functions, including red blood cell formation, energy production, DNA synthesis and brain health. It is found naturally in animal products such as meat, dairy and eggs and is essential for maintaining healthy nerve cells and producing energy.B12 deficiencycan lead to fatigue, weakness and neurological issues like numbness, tingling and cognitive impairment.Since your body stores B12 in the liver for extended periods, deficiency symptoms may only appear years after inadequate intake.
Do You Need a B12 Supplement?
Most people can get enough of this nutrient through diet, but certain groups are at a higher risk of deficiency and may require supplementation.“People prone to B12 deficiencies include those who follow vegetarian and vegan eating patterns, because B12 is not found in plant foods, and older adults with decreased absorptive efficiency,” saysLauren Harris-Pincus, M.S., RDN, founder of NutritionStarringYou and author ofThe Everything Easy Pre-Diabetes Cookbook. Certain health conditions, such as pernicious anemia and gastrointestinal disorders that affect nutrient absorption, such as Crohn’s or celiac disease, may also increase the risk of vitamin B12 deficiency, she adds. Additionally, GI surgery and medications like metformin and proton pump inhibitors may also impair the absorption of this vitamin.
Can You Take Too Much Vitamin B12?
Since vitamin B12 is water-soluble, it has a low risk of toxicity. “The body typically excretes excess amounts of B12 through urine,” explainsTrista Best, RD, a registered dietitian with Balance One Supplements. “However, taking very high doses of B12 supplements, especially over extended periods, can potentially lead to side effects. While the upper limit for B12 intake [has not been] established, avoid excessively high doses without medical supervision.”
Signs & Symptoms
Vitamin B12 is considered safe even at high doses since your body doesn’t store excess amounts. However, in rare cases, excessive B12 intake fromsupplementsmay cause unwanted side effects. Some studies suggest high B12 doses might impactkidney functionor interact with certain medications.Another potential symptom of taking too much B12 includes mild skin reactions, such as itching, rashes or acne-like breakouts.
“Speak with a health care provider before significantly increasing your B12 intake, especially if you’re on medication or have underlying health conditions like chronic kidney disease,” says Best. “Regular blood work can also help ensure your B12 levels are within a healthy range.”
Frequently Asked QuestionsFor most people, doses exceeding 2,000 micrograms per day are considered excessive, as the typical recommended daily allowance ranges from 2.4 to 2.8 micrograms.Although rare, excessive B12 intake may cause acne, rashes or impaired kidney function, as the kidneys help filter and remove excess vitamin B12 from the blood.“Surplus vitamin B12 is excreted through urine, and elevated levels typically normalize within a few days to a week after stopping supplementation,” says Best.
Frequently Asked Questions
For most people, doses exceeding 2,000 micrograms per day are considered excessive, as the typical recommended daily allowance ranges from 2.4 to 2.8 micrograms.
Although rare, excessive B12 intake may cause acne, rashes or impaired kidney function, as the kidneys help filter and remove excess vitamin B12 from the blood.
“Surplus vitamin B12 is excreted through urine, and elevated levels typically normalize within a few days to a week after stopping supplementation,” says Best.
The Bottom Line
Vitamin B12 is a water-soluble nutrient essential for several bodily functions, including red blood cell production, nerve and brain function, mood and energy. Most healthy adults get enough B12 through food. However, some people may benefit from supplementing B12, including vegans, vegetarians, people taking certain medications, and those with chronic kidney disease. Because B12 absorption decreases with age, supplements may also be helpful for people over age 65.
Although B12 supplementation is generally safe even in high doses, monitoring your intake is wise to avoid potential side effects, such as skin conditions or kidney issues. Talk to your health care provider or a registered dietitian before increasing your B12 supplementation to help ensure you maintain optimal levels for excellent health.
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SourcesEatingWell 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 Center for Complementary and Integrative Health.Vitamins and Minerals.National Institutes of Health.Multivitamin/mineral Supplements.National Institutes of Health.Health Professional Fact Sheet, Vitamin B12.Niklewicz A, Smith AD, Smith A, et al.The importance of vitamin B12 for individuals choosing plant-based diets.Eur J Nutr. 2023;62(3):1551-1559. doi:10.1007/s00394-022-03025-4Ankar A, Kumar A. Vitamin B12 Deficiency. [Updated 2022 Oct 22]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024 Jan-. Available from:https://www.ncbi.nlm.nih.gov/books/NBK441923/Capelli I, Cianciolo G, Gasperoni L, et al.Folic Acid and Vitamin B12 Administration in CKD, Why Not?Nutrients. 2019;11(2):383. doi:10.3390/nu11020383Bahbouhi I, Aboudourib M, Hocar O, Amal S.Vitamin B12 induced acneiform eruption.Heliyon. 2023;9(5):e16120. doi:10.1016/j.heliyon.2023.e16120Wu HHL, Wang AYM.Vitamin B12 and chronic kidney disease.Vitamins and Hormones. 2022;119:325-353. doi:10.1016/bs.vh.2022.01.011
Sources
EatingWell 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 Center for Complementary and Integrative Health.Vitamins and Minerals.National Institutes of Health.Multivitamin/mineral Supplements.National Institutes of Health.Health Professional Fact Sheet, Vitamin B12.Niklewicz A, Smith AD, Smith A, et al.The importance of vitamin B12 for individuals choosing plant-based diets.Eur J Nutr. 2023;62(3):1551-1559. doi:10.1007/s00394-022-03025-4Ankar A, Kumar A. Vitamin B12 Deficiency. [Updated 2022 Oct 22]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024 Jan-. Available from:https://www.ncbi.nlm.nih.gov/books/NBK441923/Capelli I, Cianciolo G, Gasperoni L, et al.Folic Acid and Vitamin B12 Administration in CKD, Why Not?Nutrients. 2019;11(2):383. doi:10.3390/nu11020383Bahbouhi I, Aboudourib M, Hocar O, Amal S.Vitamin B12 induced acneiform eruption.Heliyon. 2023;9(5):e16120. doi:10.1016/j.heliyon.2023.e16120Wu HHL, Wang AYM.Vitamin B12 and chronic kidney disease.Vitamins and Hormones. 2022;119:325-353. doi:10.1016/bs.vh.2022.01.011
EatingWell 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 Center for Complementary and Integrative Health.Vitamins and Minerals.National Institutes of Health.Multivitamin/mineral Supplements.National Institutes of Health.Health Professional Fact Sheet, Vitamin B12.Niklewicz A, Smith AD, Smith A, et al.The importance of vitamin B12 for individuals choosing plant-based diets.Eur J Nutr. 2023;62(3):1551-1559. doi:10.1007/s00394-022-03025-4Ankar A, Kumar A. Vitamin B12 Deficiency. [Updated 2022 Oct 22]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024 Jan-. Available from:https://www.ncbi.nlm.nih.gov/books/NBK441923/Capelli I, Cianciolo G, Gasperoni L, et al.Folic Acid and Vitamin B12 Administration in CKD, Why Not?Nutrients. 2019;11(2):383. doi:10.3390/nu11020383Bahbouhi I, Aboudourib M, Hocar O, Amal S.Vitamin B12 induced acneiform eruption.Heliyon. 2023;9(5):e16120. doi:10.1016/j.heliyon.2023.e16120Wu HHL, Wang AYM.Vitamin B12 and chronic kidney disease.Vitamins and Hormones. 2022;119:325-353. doi:10.1016/bs.vh.2022.01.011
National Center for Complementary and Integrative Health.Vitamins and Minerals.
National Institutes of Health.Multivitamin/mineral Supplements.
National Institutes of Health.Health Professional Fact Sheet, Vitamin B12.
Niklewicz A, Smith AD, Smith A, et al.The importance of vitamin B12 for individuals choosing plant-based diets.Eur J Nutr. 2023;62(3):1551-1559. doi:10.1007/s00394-022-03025-4
Ankar A, Kumar A. Vitamin B12 Deficiency. [Updated 2022 Oct 22]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024 Jan-. Available from:https://www.ncbi.nlm.nih.gov/books/NBK441923/
Capelli I, Cianciolo G, Gasperoni L, et al.Folic Acid and Vitamin B12 Administration in CKD, Why Not?Nutrients. 2019;11(2):383. doi:10.3390/nu11020383
Bahbouhi I, Aboudourib M, Hocar O, Amal S.Vitamin B12 induced acneiform eruption.Heliyon. 2023;9(5):e16120. doi:10.1016/j.heliyon.2023.e16120
Wu HHL, Wang AYM.Vitamin B12 and chronic kidney disease.Vitamins and Hormones. 2022;119:325-353. doi:10.1016/bs.vh.2022.01.011
