Vitamin B12 Recommendations

I have changed my vitamin B12 recommendations.

A 2010 paper by Bor et al., showed that in healthy people aged 18-50, a vitamin B12 intake of 4 to 7 mcg/day was associated with the lowest methylmalonic acid and homocysteine levels (1). They reviewed other research from the past 10 years, primarily on older populations, that reinforces this finding.

My previous recommendations were 1.5 – 2.5 µg twice per day. I have changed that to 2.0 to 3.5 µg twice per day. For supplements, I raised the lower end of the range from 10 µg to 25 µg. The daily range is now 25 to 100 µg.

You can read an explanation of my recommendations here under Step 2.

1. Bor MV, von Castel-Roberts KM, Kauwell GP, Stabler SP, Allen RH, Maneval DR, Bailey LB, Nexo E. Daily intake of 4 to 7 microg dietary vitamin B-12 is associated with steady concentrations of vitamin B-12-related biomarkers in a healthy young population. Am J Clin Nutr. 2010 Mar;91(3):571-7.

56 Responses to “Vitamin B12 Recommendations”

  1. Miles Says:

    Do you see any danger in excessive B-12 levels? I’ve been taking 1,000 mcg once a day and eating fortified foods.

  2. Jack Norris RD Says:

    Once in awhile I hear from someone who has had an acute reaction to large doses of vitamin B12. It’s not clear to me whether it’s the B12 or something else in the pill that is causing the reaction. As far as long-term problems are concerned, none have been established. That said, there is no need to take so much, unless you have B12 absorption problems.

  3. Jon Says:

    “As far as long-term problems are concerned, none have been established.”

    Does that mean: several studies find no problems with sustained high B12 intake? Or: not many studies have been done on that?

    I’m asking since I take a daily multivitamin that contains 15 µg B12 but in addition a biweekly standalone 1mg B12 pill as a “precautionary boost”. I’m thinking of cutting out the biweekly.

  4. Jack Norris RD Says:

    > Does that mean: several studies find no problems with sustained high B12 intake?

    No, it would be impractical to study such a thing as you would need tens of thousands of people with sustained high B12 intake for many years.

    Most of the B12 in a supplement of 1,000 µg will not be absorbed but will be excreted out by way of the digestive tract. Is it possible that this much B12 could be a problem in the intestinal tract? Possibly, but, in my opinion, unlikely. People taking 1,000 µg multiple times a week are likely to absorb more B12 than the average person. If we look at people who absorb more B12 on a long term basis, the research I can think of that would relate to this shows that lower homocysteine levels, a manifestation of higher B12 absorption, are linked with lower rates of mortality, heart disease and stroke.

    But, really, the best that can be said is that no one has noticed any problems with taking that much. There are no short term effects and no good reason to think that there would be any long term effects.

  5. Sandy Says:

    Is it fine to take 1000 mcg B12 supplement pills once a week?

    Thanks !

  6. Jack Norris RD Says:

    I think it’s fine to take them 2 or 3 times a week. Or possibly even every single day. But 2 times a week should be enough to maximize your B12 status, so there is no need to take more if you are concerned that it could be a problem.

  7. Steve K Says:

    Hey Jack –

    I found this company at the natural product expo in anaheim this weekend. they have this really cool product – a b12 lollipop. Can you check it out and tell me your thoughts on this?

  8. Jack Norris RD Says:

    Methylcobalamin is one of the two forms of B12 that are used by the body in the chemical reactions that require vitamin B12. The other one is adenosylcobalamin. The form of B12 found in most supplements is cyanocobalamin, which is a more stable form and thought to be more readily absorbed. Some people think it’s better to get methylcobalamin because it’s one of the forms the body uses, but all the cells of the body should be able to convert cyano- to methyl- and adenosyl-.

    That said, I don’t see any harm in this B12 lollipop, but I don’t think it’s necessary either.

  9. Ales Says:

    What are your B12 daily and/or weekly recomendations (for supplements in pill form) for vegan and vegetarian children, 1 year and up? What is the safe amount?

  10. Jack Norris RD Says:


    Cutting the dose in half for for pre-teens should work fine. Teenagers can have the same recommendations as adults.


  11. caela Says:

    Have you any thoughts on the effectiveness of B12 patches? I’ve been thinking of trying them.

  12. Jack Norris RD Says:


    Since supplements work well, I haven’t taken the time to research B12 patches.

  13. Amanda Says:

    But what is the significance of these “biomarkers”? I eat fortified foods regularly, but probably not on a daily basis, and probably not close to the recommended value. What will happen to me if I don’t take a supplement? I am 19 and I have only been vegan for two years.

    I read somewhere, and I thought it was here, that there is some evidence to suggest that healthy people need hardly any B12 because it can be stored and used in the body for very long periods of time. And that usually severe B12 deficiency in developed countries is caused by nondietary problems (I might be confusing it with another nutrient though).

    Sorry, I don’t know where else to ask these questions…

  14. Jack Norris RD Says:


    The main worry is that you might develop high levels of homocysteine which, over many years, could cause an increased risk of heart disease, stroke, dementia, and early death.

    > I read somewhere, and I thought it was here, that there is some evidence to suggest that healthy people need hardly any B12 because it can be stored and used in the body for very long periods of time.

    You definitely didn’t read that here! We’ve known for 10 years now that the body does not store enough vitamin B12 to keep homocysteine levels in check for more than short periods of time.

    You might want to check out this page:

    If you are not eating fortified foods in the amounts I’ve recommended, then you should probably opt for one of the two supplement options. They are not hard to do.

  15. Amanda Says:

    Do you know if the recommended daily value on fortified foods, such as Silk soymilk, is the one you are recommending, or is it lower?

  16. Jack Norris RD Says:


    The Daily Value on fortified foods is based on 6 µg.

  17. Leslie Goldberg Says:

    What about just eating brewer’s yeast or nutritional yeast and skipping the pills?

  18. Jack Norris RD Says:


    Eating fortified foods is fine and is mostly how I get vitamin B12 (I take a 1,000 µg pill once in awhile). But brewer’s and nutritional yeast do not have vitamin B12 unless they are fortified with it. You also have to take care not to let them sit out in the light as that can damage B12.

  19. Alice Says:

    I totally agree with increasing the recommended intake of B12, based on my personal experience as well as the recent research findings. I developed a B12 deficiency despite taking a supplement containing 10mcg every day since I gave up meat. I had tests done which showed that my absorption of B12 is normal, so the deficiency was caused by inadequate intake rather than poor absorption. Given how serious B12 deficiency can be, nobody should be taking the risk of inadequate intake.

  20. Caroline Says:

    Hello, sorry to spam an old post, I didn’t know who else could answer my question…
    I was wondering what you think about the Vegan Society multivitamin, Veg-1… I’ve never seen it mentioned in your different recommandations and just noticed that it contains only 10µg of B12. Which, according to you and the unfortunate person preceding my comment, is not enough.
    I’ve been thinking of taking two pills daily instead of just one, but I don’t want the rest to become a problem because of an excessive intake (vitamins B2 (1.6mg), B6 (2mg), D (10µg), iodine (150µg), selenium (60µg) and folic acid (200µg)). Should I keep taking this one and another B12 supplement? Or maybe another multivitamin would be better?
    We have no fortified food in France and vegan supplements are not easy to find, that’s why I’m taking this one… (silly anti-vegan politics).

  21. Jack Norris RD Says:


    > it contains only 10µg of B12. Which, according to you and the unfortunate person preceding my comment, is not enough.

    There is a difference between “enough” and “ideal.” 10 µg should be enough to prevent any sort of overt B12 deficiency and keep homocysteine levels relatively low. I would not take 2 per day.

  22. Tamara McFarland Says:

    Hi Jack,

    I just purchased some Nature’s Bounty Sublingual B12 tablets – they are 2500 mcg each and the label says to take one a day – that seems excessive based on what has been posted here… I was thinking about doing one once a week for me and a half of a tablet once a week for my 6-year-old son.

    We both also take a multivitamin daily that has 6 µg B12.

    Does this seem like a reasonable plan?


  23. Jack Norris RD Says:


    I would cut the pill in half and take one half two times a week for you, and cut it in quarters and have your son take one quarter two times a week. I am basing this on my chart here:

  24. Tamara McFarland Says:

    Thanks! That makes sense, I was just doubting my math or something since the bottle says to take a whole one every day! 🙂

  25. puzzled Says:

    I am a little puzzled at the B12 recommendations you list in the table at

    If I’m reading that table correctly, adults should get 2.4 ug based on the US RDA, but the recommendation is 25ug – 100ug per day.

    However, where it gets confusing is it also lists 2 – 3.5ug as the “2 Doses per Day” recommendation. That’s 2x the US RDA, but only a tiny fraction of the recommended daily dose. Why? And why is the recommended 2x weekly dose of 1000ug 10x the maximum recommended daily dose?

    I understand that some people may prefer to take their B12 once per day, or twice per day, or twice per week, but shouldn’t the doses all add up to the same amount per week? That is, if the recommended daily dose was 100ug, shouldn’t the recommended weekly dose be 700ug, not 2000ug?” (Based on the maximum daily recommendation of 100ug)

  26. Jack Norris RD Says:


    I list the US RDA in that table simply as an fyi. The reason I do not simply suggest that vegans meet the US RDA is because:

    1. The RDA is based on what intake of vitamin B12 will prevent macrocytic anemia, rather than what amount will lower homocysteine and methylmalonic acid to optimal levels. My recommendations should accomplish all of these things.

    2. The RDA is intended for people who are eating B12 multiple times a day as most omnivores do.

    When you are getting your vitamin B12 in 2 doses or less per day, the amount of vitamin B12 that can be absorbed at one time becomes an issue. The are 2 ways to absorb B12: via transport proteins (called intrinsic factor) and by diffusion. The intrinsic factor route becomes saturated at about 1 to 1.5 µg per day. Anything above that ingested at the same time will only be absorbed at a rate of about 1 to 1.5%. So, as the frequency of taking B12 goes down, the amount rises rather steeply.

    I explain all of this in a lot more detail in How Recommendations Were Formulated of Vitamin B12: Are You Getting It?

  27. Nick Says:

    This might be a silly question, but going by the recommended values, what would be the best way to proportion a 500 mcg B12 supplement? Can I just take two twice a week to meet the ~1000 mcg recommendation? Or take one every other day? This is for a vegan diet and having no known B12 deficiency.

  28. Jack Norris RD Says:


    Not silly. But the answer is to combine them to make a 1,000 mcg tablet and take 1,000 mcg twice a week. You’ll actually absorb more if you take 4 by 500 mcg per week at different times, but that isn’t necessary.

  29. Eva Says:

    I am a lacto-ovo vegetarian that has Pernicious Anaemia. As I am sure you must know, this means I cannot absorb B12 through my gut and have to have periodic injections. I am struggling with my doctor at the moment to get him to realise that I need my injections much re frequently than every 3 months (which seems to be the blanket norm for all PA sufferers – unless you have a doctor who really understands the disease). I just about get through a month before the PA symptoms begin to erupt again. I have persuaded him to change me to 2 monthly injections but still struggle through he second month, spending many days at home too weak to do very much. This disease will be with me for life and I try and read as much as I can about it so that I can manage it as we’ll as possible. However, the doctor has agreed to run some more blood tests and I am due to have one tomorrow to see what my B12 levels are. One of the problems that I face is that I have been taking a multi vitamin and realised a couple of days ago that The B12 content of the supplement would give a false reading on my blood test. I stopped taking the supplement a couple of days ago but wonder if the B12 would still be present in my blood. I realise B12 is water soluble, but how long would it take to clear from my blood. Another question I have for you is hat I have read that B12 can be stored in the liver for 3-5 years. How is this possible if it is water soluble? Look forward to your reply.

  30. Jack Norris RD Says:


    Why do you think B12 from a multivitamin can give a false reading on a B12 test? From what I know, that would not be true.

    > I have read that B12 can be stored in the liver for 3-5 years.

    All that means is that someone can build up a supply of B12 in their liver such that if they no longer have a dietary source of vitamin B12, they would have enough B12 to prevent overt deficiency symptoms from appearing for 3-5 years. However, the number (3-5) is arbitrary, it depends on the person and how much B12 they had eaten, and it wouldn’t apply much to people with PA. The liver can store B12 on proteins, it doesn’t matter if it’s water-soluble.

  31. Eva Says:

    I should have said I take the multi vitamin supplement daily

  32. Erin Says:

    I am still very confused about whether a vegan multivitamin is sufficient in getting enough B12. I currently take VegLife , , which states it has 100mcg as cyanocobalamin and %1667 of daily values. I am also now questioning whether it has a sufficient amount of the other vitamins as well. If you could help clarify this I would really appreciate it. Thank you so much

  33. Jack Norris RD Says:


    Here are my recommendations:

    100 micrograms per day should be enough.

    I leave it up to each individual to determine how they meet the recommendations, assuming they choose to, as there is no way I have time to counsel everyone on how to do it given their circumstances. Here is what I supplement with:

  34. Humprey Says:

    Hi sir Jack!

    How are you doing?

    I have another question about your recommendation:

    You recommend us to take 2000mg daily for 2 weeks, and after that we would shift to step 2, which has an option to take 1000mg twice a week. You explicitly state that the recommendation is for cyanocobalamin only.

    What if I have 1000mg/tablet of pure cobalamin? I just have bought a B-12 supplement from Healthy Options but I didn’t notice until I got home that the 1000mg is cobalamin not cyanocobalamin.

    Would your recommendation, in this case, not hold? What would you recommend me then?

    Also, if I may, I want to ask what do you think about Chelated Zinc vs. Zinc Gluconate? I also bought a Chelated Zinc (30mg, tablet) as a replacement for my old Zinc Gluconate (tablet, chewable). The chelated says it utilized technique for greater absorption through amino acids, while the gluconate is chewable (which seems to me enhances absorption). Or perhaps I can also chew the chelated (although it probably wouldn’t taste as good as the chewable gluconate!)? There’s also another version (which I forgot the name) of zinc that is capsulated (Gelatin), which they said is better than the chelated one.


  35. Jack Norris RD Says:


    This is all I know about zinc absorption:

    I have no idea if what they’re saying about chelated zinc is true. Sorry!

    As for the B12, I’m pretty sure there can’t just be “cobalamin”, it has to have a side group (methyl, cyano, hydroxo, and adenosyl being the most common). I tried to search for the company to see if I could figure out which type it was, or if they are using a questionable method for determining how much B12 is in their product, but I couldn’t find it. If you can find a link, post it and I will check it out. In the meantime, in my opinion, it’s most likely cyano.

  36. Humprey Says:

    Sir Jack,

    Thanks for the link. Seems there’s no Chelated Zinc there, would that mean you preferred my chewable Zinc Gluconate? And how about my question whether chewing the chelated tablet (or any tablet, even not advised) could make it better absorbed?

    Yap, I actually thought of that exactly, that it seems cobalamin should come with some forms. That makes me wonder of the reliability of this.

    And that made me thought of this questions: Ins’t cobalamin another name for Vitamin B-12 and cyanocobalamin is a compound of vitamin B-12 + cyanide? If so, then how much % cobalamin will there be on a cyanocobalamin?

    Could it be that when it says 1000mcg cobalamin it means there’s 1000mcg of vitamin B-12 *aside* from its other constituents (albeit wrongly unnamed))? Say there’s also 1000mcg of cyano/cyanide which made a single tablet really 2000mcg of cyanocobalamin, and since it’s the B-12 that is important that it alone was put on the nutritional facts?


  37. Jack Norris RD Says:


    > Seems there’s no Chelated Zinc there, would that mean you preferred my chewable Zinc Gluconate?

    No, it just means I haven’t researched chelated zinc.

    > And that made me thought of this questions: Ins’t cobalamin another name for Vitamin B-12 and cyanocobalamin is a compound of vitamin B-12 + cyanide? If so, then how much % cobalamin will there be on a cyanocobalamin?


    I’m not sure why some companies only list “cobalamin” or what it actually means. I’m not sure they even know what they mean by it. But the cyanide component of B12 is very small compared to the rest of the molecule.

  38. Humprey Says:

    Sir Jack,

    >No, it just means I haven’t researched chelated zinc.

    Ok. How about my “could-chewing-enhance-absorption?”

    >I’m not sure why some companies only list “cobalamin” or what it actually means. I’m not sure they even know what they mean by it. But the cyanide component of B12 is very small compared to the rest of the molecule.

    Oh I see. So I think it’s ok. I’m thinking that if the “cobalamin = 1000mcg” means there’s a total of 1000mcg of cobalamin per tablet, and the cyanocobalamin’s composition would be something like 50/50 (cyanide/cobalamin) then I would be taking 2x greater than the recommended.

    But you seems to say that the cobalamin on a 1000mcg tablet would be something greater than 95%, so I think even the worst case isn’t that bad.

  39. Jack Norris RD Says:


    > How about my “could-chewing-enhance-absorption?”

    It could, but only if your digestive system is too weak to break down the tablet on it’s own. This is possible, but unlikely.

  40. Humprey Says:

    Sir Jack,

    Good day!

    I have another dumb question:

    It seems recommended to take supplements after meal. What if, not too long, say 30 mins, after meal you will be having a Bowel Movement, would you prefer taking the supplement after or it is ok to take it before the Bowel Movement.

    I’m thinking that maybe if you took it before, then the Bowel Movement would render it less absorbed.


  41. Jack Norris RD Says:


    It doesn’t matter when you take vitamin B12.

  42. Humprey Says:

    Sir Jack,


    Also, what about Zinc? When is the best time it should be taken? Would it also be good anytime?


  43. Jack Norris RD Says:


    I think you have started to cross over from legitimate questions about my posts into personal nutrition counseling. If you’d like to have a professional counseling session with me, let me know. Thanks.

  44. Jenna Says:

    Hi Jack,

    Just a question about the B12 recommendations: In the B12 Recommendations section, it mentions two doses per week of 1000 mcg for someone in my age group (14-64) as an option. Should the B12 pills be cut in half and taken throughout the day or should I just take one whole B12 pill each time I am scheduled to take one?

    Also, are you still accepting donations for your site? I wasn’t sure if the pay pal section was for donations or the PeaCounter or both?

    Thanks again for all that you do in bringing valuable information to the vegan community!


  45. Jack Norris RD Says:


    Those recommendations assume you are not breaking the pills in half and taking twice a day, but that’s better to do if you are willing.

    > Also, are you still accepting donations for your site? I wasn’t sure if the pay pal section was for donations or the PeaCounter or both?

    Thanks for asking! Yes, it is for both for donations to and

    Thank you.

  46. Serene Says:


    I would like to know that is it safe to consume methylcobal (mecobalamin) tablets by breaking them into half? I feel thirsty when I take 500 mcg tablets, so I was wondering if I could break them into half. Will the broken tablet go bad if I take it the next day?

    Thank you

  47. Jack Norris RD Says:


    I don’t see why that would be a problem, though it seems that people need to take at least 1,000 µg per day for methylcobalamin to work.

  48. Tara Says:

    Hi Jack,

    I am a vegan RD who works with vegan and vegetarian clients and I love your website. I recently wanted to look up the vitamin B12 recommendations for vegans (if I remember correctly, you had it written as a 2-Step process, during which time someone would take 1000 (?) micrograms daily for two weeks, and then switch to a much lower dose. When I click on your link “Vitamin B12 Recommendations”, I am taken here (, a page that says “Oops, Page Not Found.”

    Has this page been relocated? Any advice you have on how to access it would be much appreciated!


  49. Jack Norris RD Says:


    I got rid of the 2-step process and only have the daily recommendations which are here:

    I’ve heard many reports of acne-like symptoms from large doses of B12 and I don’t think the first step was necessary for most people. I’m also trying to simplify my recommendations. For those reasons, I only have the one step now.

  50. Laura Harrison Says:

    Hi Jack,

    57-year old female vegan with an odd b-12 problem. I have difficulty supplementing b-12. Even smaller doses cause me insomnia. I managed (with great difficulty) to find 25 mcg vegan tabs by Lifeplan. The whole pill keeps me up all night and cutting them in half hasn’t worked either. I recently acquired Vegan for Life and decided to try fortified soy milk. When I had a cup at breakfast and one at lunch, I felt great. Energy was good, really perked me up. But then up all night even with that tiny dose, which is only lie 6 mcg total, is that right? I don’t do any caffeine. So then I tried cutting back to one cup of soy milk a day. That seems to be the sweet spot. I feel good during the day and am sleeping beautifully. Have you encountered anyone with a similar sensitivity to b12? I am small, about 98 lbs and super sensitive to stimulants. Even tiny amounts of coffee, chocolate or green tea mess my sleep up. At one time I attempted to take vitamin c and that also caused insomnia. I had a b-12 injection which caused about 3 weeks of crap sleep. I once drank a red bull and was up for 2 days. My serum b-12 when last tested was 279. Not great, not horrible. I’ll stick with the 1 cup/day soy milk and get re-tested in July. I may have to live with the fact that I am never going to achieve very high levels because of my diff. with supplementing. Any ideas? Parents may want to pay attention to their children’s sleep patterns after giving higher b12 doses. Or maybe it is just me. I read that b-12 can lower melatonin levels and that seems to be what happens with me. I can get to sleep, but can’t stay there.

    Thanks for reading,

  51. Laura Harrison Says:

    Hey Jack,

    Forgot to add that my MMA result was 212 nmol in July of 2017. I was drinking raw milk then. I drift back to that occasionally as a result of my frustration with the b12 issue. However, I did quit dairy (again) in Aug. of 2017. Don’t know know what my current MMA is. Dairy serum level was 275, non-dairy was up 4 points at 279, but I had been haphazardly attemping to supplement.

  52. Jack Norris RD Says:


    I’ve never experienced someone not being able to sleep from B12 supplements or someone being negatively affected by such small amounts. If you’re getting B12 from two or more doses of fortified soymilk, you only really need 2.4 µg per day to meet the RDA. Just cut the soymilk down by enough to get 1.2 µg per serving. But you probably should get your B12 status checked once a year under this regimen to make sure it’s enough.

  53. Annika Impallomeni Says:

    Can too much B12 ie one tablet 1000 per day cause tingling in hands and arms, very mild.

  54. Jack Norris RD Says:

    Infants suffering from severe B12 deficiency due to inadequate intake, who then are given large doses of B12 to correct the deficiency, have experienced some strange temporary symptoms, though I haven’t seen anything similar documented in adults. If your tingling doesn’t resolve after a few days, I’d consult a doctor. If you don’t have severe deficiency, then cutting back to 1,000 twice per week (if using cyanocobalamin) would be a maintenence dose of B12.

  55. ricky Says:

    Hello i have a question i had blood work done andbmy b12 levels were 300 my doc told me to take 3000mcgs dailey isnt this a little high of a dose i tried it for the first time and it had me feeling hyper and anxious for hours after tsking 2500mcgs quick dissoolve and can i split this type of vitamin in halfs even quarters?

  56. Jack Norris RD Says:

    If the units for your B12 level was pmol/l, then your levels are enough. If the units were pg/ml, then increasing them to 400 wouldn’t hurt, but no need to take nearly that much only based on your levels. 1,000 mcg twice a week is enough for most people.

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