Doctor's Note

Want more on B12? Check out these videos:
Vitamin B12 Necessary for Arterial Health
Daily Source of Vitamin B12
Safest Source of B12
New Vitamin B12 Test

For some context, also check out my associated blog posts: Vitamin B12: how much, how often? and Vegan B12 Deficiency: Putting It into Perspective.

If you haven’t yet, you can subscribe to my videos for free by clicking here.

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  • Michael Greger M.D.

    Check out my blog post Vegan B12 Deficiency: Putting It into Perspective to put this subject into context.

    • *likes*

    • Rick1

      Hold on Doctor Greger, a bigger study was done in the U.S. back in 2000, and it clearly showed that even 39 percent of meat eaters are B-12 deficient, so don’t automatically believe that 1% stuff regarding British meat eaters, that the British study showed. Bottom line is everyone should take a B-12 supplement. Sublingual tablet, or shots, are best, as you know. Anyway, below is the 2000 study link.

      • Michael Greger M.D.

        No, if you read that page you linked to 39% were found to be “low normal,” not deficient. Either way the best way to get B12 is through healthy fortified foods and supplements. I try to put the whole issue in perspective here:

      • Kathie Jamison Cote

        Come on Rick! – this study is put out by the USDA – you really believe their statistics? The say people should be eating about 30% fat!!!! When in healthy actuality humans should only ingest about 10% fats! They also say we need more protein than we do! They’re idiots and that’s one of the reasons this country is in the horrible health that it is!

        • David San

          3-5 years later, i want to add, that maybe this low normal group is now deficient or a part of those 39%.
          it goes down with humanity. you know that. more and more people are really fat, unhealthy, unenergetic.
          and only 1% are vegans. so enough people are deficient in a lot of stuff. also brain cells ;)
          sure, if our gut and absorption doesn’t work, you can eat as much as you want and it doesn’t help you.

  • Puzzling, as so many alternative milk products are well fortified. Don’t these people eat cereal or oatmeal where they could easily use fortified soy/almond/rice milk etc.? Or is fortification not a reliable source, does only direct supplementation meet the criteria? If the latter is the case, I am afraid this will only be a growing problem. Most people cannot be trusted to take care of themselves (self medicate with B12 in this instance).

    • So true, but I know vegans who purposely avoid the fortified soy milks in favour of the “organic” ones and same with cereals etc, so they are missing alot of the easiest ways to get their B12 cause they think it’s a myth.

  • mainlinebooker

    How often should you have your B12 measured? I just had mine done and without any supplementation, I have normal levels..

    • Michael Greger M.D.

      Please see my response below at the bottom.

  • mainlinebooker

    ps. I am a 60 year old vegan with a normal liver!

  • imgreen

    Please tell us what is is a sufficient supplement? Is fortified nutritional yeast, fortified rice milk sufficient? How much (i.e. in tablespoons or cups) is adequate?

    • Michael Greger M.D.

      Please see my reply below–thanks for that important question!

  • LouiseF

    It’s shocking because its so easy to take a supplement daily or even a few times a week. Get with it Brits, don’t give vegans a bad name!

    • lol. Is this a joke? I’m sure the same is true for American vegans.

  • If you’re in the UK and drink soya milk just buy fortified soya milk (i.e. not organic) with your cereal and you’re there! 250ml provides the RDA. Also, crappy keloggs cereals are all fortified so you don’t need to fork out for expensive suppliments every day.

    • I think you kind of missed the point of the video. It wasn’t an attack on British vegans, but rather uneducated/misinformed vegans. There’s plenty of them out there everywhere. There just isn’t an equivalent study done on Americans or others (as far as I know). I’ve talked to many American vegans that don’t see why they should take B12 supplements as “nature has provided all the nutrients we need” and “meat eaters get B12 deficiency too”.

    • Lyndon

      Drinking fortified soy milk is NOT the answer in the U.S. Unless we buy organic soy products over here, we’re more than 95% likely to be consuming GMO soy. I’ll take a B-12 supplement instead. Thanks.

    • Thickbloke

      Some of the additions to Soy milk are NOT Vegan. Same goes for fortified cereals!

  • I’ve just read that the “best” way to supplement B12 is either a daily intake of 100µg or to take 1000µg twice a week, better if it is showed.
    Those people that don’t take their b12 really give vegans a bad image, instead of people seeing how great and healthy they will be when following a vegan diet, they see these horror stories one after the other and the worse thing is that the media seem to focus enormously on these sick people more than they would focus on people who recovered from heart illnesses or slowed their cancer enormously with a vegan diet.
    The best thing a vegan can do to promote the diet is to look great and tell people how he did it.

    • Well said!

      • beansngreens

        Exactly! Especially when the B12 vitamins and fortified foods are completely vegan.

    • bakp

      So well said! I am vegan and you are RIGHT! If you catch a cold people say it is because you are not getting enough of the “right” foods ..too sad!

    • Lara_H


      It would almost be better that those people who are not informed about this should not be vegan at all. It could even be outright dangerous to not get enough B12. and gives veganism a bad name.

      But it still puzzles me, how hard can it be to take a tiny pill of B12 each day or a few times a week?? It is such a small task, but such an important one.

      • John Furr

        So better for animals to die because some one is ignorant of how to manage their health? I think a better solution would be that we educate the misguided vegans..

  • MsAdventuress

    I’m so grateful to hear all this, spelled out. Doctors need to watch these videos, too! ♥

  • healthcoach7

    In reading this info I wonder if any of you have read the book “The Whole Soy Story by Kaayla Daniel. Soy is not recommended for babies, children, women who are trying to conceive, women in perimenopause basically everyone. Soy should NOT be eaten unless it is fermented, ie, miso, tempeh,natto etc. Phytoestrogens are precursors for breast cancer and infertility. Soy products are being forced down our throats just like corn products and neither one are healthy. Chinese women feed their unfaithful husbands soy. Soy was never intended as a food and only in the US is it subsidized and put in over 60% of our food.

    • Michael Greger M.D.

      Please see my response below.

    • kevint

      Daniels is a shill for the Weston Price ppl, and spreads misleading or outright false information that has no scientific backing…if you check her “sources”, they all lead back to WAP, affiliated groups, or her…

  • I agree that fermented soy products are most healthful, but I disagree with your general condemnation of soy. In fact there is evidence with specific diseases it may be helpful.

  • Excellent video!
    Vegans should take B12-supplements, period.

  • mainlinebooker

    Hoping Dr.greger will answer my question about how often to test if B12 is normal and no liver issues..

    • Michael Greger M.D.

      Please see my response down below.

  • That’s why I take a multi with B12 in it, and a B12 sublingual once a week!

  • Michael Greger M.D.

    Sorry it took me so long to reply (Irene knocked our power out!). First let me repost the recommendations I added to the B12 blog entry:

    In my opinion, the easiest and cheapest way to get our B12 is to take at least 2,500 mcg (µg) cyanocobalamin once each week, ideally as a chewable, sublingual, or liquid supplement (you can’t take too much–all you get is expensive pee).

    Or, if you’d rather get into the habit of taking something daily (instead of once-a-week), I recommend at least 250mcg (I know the math doesn’t seem to “add up” but that’s due to the vagaries of the B12 receptor system–I’m going to post a video on how I arrived at these recommendations soon).

    Or, if you’d rather get it from B12-fortified foods, I’d suggest three servings a day, each containing at least 25% of the “Daily Value” on its label (again, I’ll explain). Such foods can be as exotic as a certain type of “nutritional yeast” or as simple as a bowl of Cheerios.

    One would assume all products such as soymilk (soya for you, Peter :) and plant-based meat substitutes would have B12 added, but sadly that’s not the case. You just have to look at the label. Once one starts looking on packages you might be surprised how frequently you’ll find it in often unexpected places (such as Celestial Seasoning’s “tension tamer” tea).

    imgreen: In terms of what constitutes a sufficient serving (see above) of various fortified foods, typically this would mean a half a cup of most soymilk brands (though a cup for one popular rice milk), a cup of most popular (i.e. loaded with added sugar) breakfast cereal brands, a heaping teaspoon of B12-fortified nutritional yeast (not all is fortified), one veggie hot dog, five slices of veggie bologna, etc. You should check the label, looking for the “25%” next in the B12 Daily Value box (see above).

    In my 20 years eating a plant-based diet, I’ve personally found the cheapest and simplest method to just take the once-a-week supplement I described above, which if you share with a bunch of friends can cost as little as $2 a year — cheaper than Cheerios! :).

    mainlinebooker: At your age (over 50) everyone should be supplementing with vitamin B12 regardless of their diet according to the Institute of Medicine (the official body that brings us the “Recommended Daily Allowances”). Because your physician likely doesn’t know any better, you probably got a serum B12 level drawn (a relatively specific but insensitive test). So a “normal” vitamin B12 blood level does not rule out even potentially severe B12 deficiency. There are better tests your doctor can order, such as a urine MMA level (“methyl-malonic acid,” though there appears to be an even better test on its way–I’m planning to record a new video about it), but I’d recommend you just follow the IOM recommendations and supplement.

    healthcoach7: There certainly is all sorts of crazy stuff on the internet about soy (and just about everything else I imagine). Thankfully the public appears resilient to such internet rumors (at least according to a United Soybean Board survey released last week). You may find this article by author John Robbins useful. I can’t vouch for everything he writes (haven’t checked his sources), but it’s his response to the kind of legume defamation you describe :)

    • tonyattanasio

      Just two naive questions–how much research has been done into “vitamin-B12 deficiency” after the first studies between the end of the 1920’s and the end of the 1940? And how many of us are still relying in Prontosil to treat infectious diseases?

  • Awesome. No Irene effects here. Colorado is a long way from the east! I think that 2% milk I drank last week has me in the black. Not a vegan yet- but this site has me thinking….I’ve never been vitamin tested at all to my knowledge. Hmmm……………

  • My question is what type of B12?? I keep reading in many blogs and articles that the most potent form of vitamin B12 is methylcobalamin and not cyanocobalamin (the one I’ve been taking for over a year now).
    To tell you the truth, I’m really scared I may be harming my body!
    Dr. Greger, do you have a justified answer to this? If so, please enlighten me.

  • Great info. I recently began taking a sublingual form of B12 and have been pleased to see my energy levels steadily increasing. I have anemia also, the cause of which my docs haven’t been able to pinpoint. Hoping I see improvement in this area also.

  • Kim

    One of the comments mentioned liver issues. Is a deficiency in B12 related to liver issues? During a preventive visit to my doctor she said I had slightly elevated AST and ALT levels. She said she was puzzled as I don’t drink, don’t take tylenol (or any medications, except a 3 day course of Nutrofuran 3 months ago for a UTI) am not overweight, exercise regularly. I told her I rarely eat animal products. (Note: I am now taking a supplement after watching your video).

  • KJ56

    Nutritional yeast is commonly used by the vegans I know. It is a tasty addition to many dishes, and provides 130% of the daily B12 requirement in 1 1/2 T. Shouldn’t that be enough? It also has other B vitamins. Love this site by the way, new discovery.

    • Yes, this is my primary source of B12 in addition to daily consumption of fortified nut milks. And it does taste great in many dishes!

  • GregV

    I live in Phoenix and try to sun 20 minutes a day at 11am. I have heard that after you sun, you should not use soap on the majority of your skin for 24 hours in order to allow the surface B12 to be absorbed. I would like your thoughts on this information?

    • Toxins

      Hello GregV,
      You actually do not absorb vitamin b12 through your skin, what you are referring to is the absorption of vitamin D. Humans cannot create their own b12 and must obtain it from outside sources, such as through supplementation. Check Dr. Greger’s video to see that you should be getting 15-30 min. per day of pure sunshine in the summer for adequate vitamin d levels as well as supplementing vitamin b12. Also note that getting sun on your head and arms is probably not enough, you should lay out with as little clothes as possible, like wearing a swimsuit. Also note that in the winter is extremely difficult to get adequate vitamin d absorption. Regarding bathing after tanning though, it has been discussed by Dr. John Cannell that a significant amount of vitamin D is produced on the surface of the skin and may in fact require absorption for adequate levels. The scientific literature states that vitamin d is produced deep within the skin, although this is true, it is only half the story. In the words of Dr. Cannell “Holick, et al’s, landmark 1980 study showing most human Vitamin D production occurs in the deep epidermis was incomplete. It was based on surgically obtained (and assumedly surgically prepped) skin samples that had any remaining surface oils removed by washing with hot water. Indeed, to accurately address the question of where Vitamin D is made, one would need to obtain unwashed human skin, difficult to do even from cadavers.” Right now it is unclear where most of the vitamin D is created as their isnt enough research on the subject. You could go with Dr. Mercola’s theory of not bathing for 48 hours for adequate absorption. Due to our modern era, its hard for tanning to be a reliable and consistent source of Vitamin d. Most doctors recommend between 2,000 to 4,000 IU’s of vitamin d per day. You could supplement a lower amount and also tan just to be on the safe side. If you are really curious, you could also get a blood test now and another one a month later to see how well your vitamin d levels are. Hope this helps!

  • GregV

    I did mean Vitamin D, sorry. My head is a bit spinning from all the great info i’m getting from this site!

  • becochic

    The B12 stuff keeps making me nervous about raising my baby on a vegan diet, but while eating the SAD junk diet I was low in iron and b12! I ate animal products constantly.

    • Rick1

      Nothing to be nervous about, just get a good book on how to raise a baby on a healthy vegan diet. Check out a show called ‘It’s all about food’ with Caryn Hartglass. Anyway, email her for book advice on the subject of raising a child vegan. You can find her show at

  • Mark Biddy

    does rain water contain b12 or any other micro/macro nutrients?

  • I am still confused about B12 (and I think many are)
    I have not taken regular supplements of any kind and have been vegetarian for 13 yrs and vegan the past 3 yrs. I recently had a blood test and my B12 was ‘on the high side’ at 811 (the normal range was something between 200-900) Now I keep reading all these things that say vegans need to supplement so just to be ‘better safe than sorry’ I now pop a B12 supplement every once in a while (I also use nutritional yeast in my cooking quite often)
    Here’s why I am still confused, my understanding is that people who eat animals get their B12 (which I’m told is a bacteria not a vitamin) from the animal products. When asked how the animals have B12 and we don’t (when these animals are vegan too, like cows)
    I’m told that the cows eat the grass off the ground and because its not washed and the ground is teeming with bacteria including the B12 bacteria, the cows ingest it this way….so if the cows ingest the Bacteria how does it get into their flesh? Also how does eggs and cheese have B12 ? Do certain animal products have more B12 than others? Also if B12 is a bacteria and it somehow gets transferred from the cows’ stomachs to their flesh, people cook their meat before eating it specifically to kill bacteria so wouldn’t the B12 bacteria be killed too?
    Also there are meat-eaters who have B12 deficiency as well as many other deficiencies, in fact based on my personal experience the people I have known who had any deficiencies were non-vegans but anytime I tell someone I’m vegan (including other vegans these days) I’m told I need to be very careful to supplement with B12 because my vegan diet is not adequate. In addition to answering my questions posed, Dr. Greger, can I suggest that you put together a chart or visual showing all types of deficiencies and how nutrient deficiencies in general compare from vegans to non-vegans…because it would be my guess that non-vegans do suffer more deficiencies than vegans but everyone just focuses on this one mysterious bacteria called ‘Vitamin B12’. I would also suggest to be more accurate that people stop calling it a vitamin if it’s a bacteria, this confuses people too. With all the weird info about B12 I see that in a few years it will be like the ‘pluto phenomenon’ where for so many years scientists said pluto was a planet and now they say actually pluto is just a moon…I suspect with more research into this topic, it may come about that B12 ‘deficiency’ has nothing to do with a vegan diet or its not the way we thought it was. Thank you for answering my questions.

    • Toxins

      Hello Rebecca, I see you have much concern for b12, let me explain.

      B12 is a byproduct of bacteria, not the actual bacteria itself. We use very tiny amounts of b12 everyday so we wont find deficiencies until 20 years have passed in some cases. Nutritional yeast has a daily amount of b12 but if your taking a sublingual supplement with a big dose, then you only need to do this once a week. It doesn’t matter if you take too much though because if you take excess b12, you pee it out.

      Dr. Greger explains b12 in many of his videos, particularly this one.

      Also, Dr. Greger does in fact show a comparison in this video of omnivore and vegan nutrient deficiencies.

      I know that the best b12 supplements are the sprays or sublingual ones but I do not know how effective the pills that you swallow are. Cows achieve b12 because they grow that bacteria in their gut flora, we do not.

    • veggiedude

      You say you’ve been vegan for only 3 years. I’ve heard people can go up to 20 years before becoming B12 deficient.

  • Rick1

    Hold on everyone, a bigger study was done in the U.S. back in 2000, and it clearly showed that even 39 percent of meat eaters are B-12 deficient, so don’t believe that 1% stuff that the British study showed. Bottom line is everyone should take a B-12 supplement. Sublingual tablet, or shots, are best. Anyway, below is the 2000 study link.

    • Michael Greger M.D.

      That was from the Framingham Offspring Study. I actually have a video coming out about it soon, so stay tuned! 39% didn’t qualify as deficient, though, as you can read but just “low normal.” I agree though, that supplements are fortified foods are the best cholesterol-free source of B12 for everybody.

  • David tunison

    I ahve followed you for years and purchase your tapes. Met you in Ann Arbor at the food co- op.Is it true Cyanocobalamin b12 ( which you recommend for us as vegans)turns into cyanide and the best b12 to take is hydroxycobalamin?Per Raymond Francis MIT scientist. That’s what his website shows anyway. His comments were it is man made , not natural, and not well utilized. What is absorbed is turn into cyanide. Could you please clarify, help.

    • Michael Greger M.D.

      Let me guess: Mr. Francis sells hydroxycobalamin supplements? It’s like the whole coral calcium scam. Calcium is cheap as chalk–in fact it is chalk! So how are you going to bilk people out of lots of money? You sell some sort of special calcium. Same with B12 supplements. They are so cheap to produce that supplement manufacturers try to come up with all sorts of fancy ways to “add value” to products so they can charge $30 a bottle. Unless you’re a smoker, have kidney failure, or base your diet around cassava root, cyanocobalamin should be fine.

  • vegan gary

    Hi M ichael

    My wife and I are vegans and we take B12 supplement. I have a couple of questions:

    – we use methyl B12 1000 mcg 2/week. You often discuss the necessity of taking B12 for vegans. We swapped to methyl B12 as a workmate said the cyano B12 was unhealthy? I see from your site you recommend the cyanocobalamin and that methyl is expensive and unecessary. Is the methyl just as effective?

    – why is taking B12 as a supplement healthy and taking other vitamins as supplements unhealthy. I understand the argument for other supplements goes like this: taking supplements overloads the receptors on the cell for that group of vitamins and therefore other vitamins within that group can’t be taken up and imbalances occur. If that is correct, why doesn’t this happen for B12 in relation to uptake of other B vitamins. There seems also to be an issue about taking your nutrients in the context that they came from eg having an orange rather than drinking orange juice for vitamin C. How does this relate to B12?
    By the way congrats on nutrition facts. I have sent it to my kids but they haven’t become addicts yet!
    Thanks Gary

  • Kelli

    I don’t buy these numbers, either, at least not in America. The Standard American Diet is conducive to digestive problems. It takes intrinsic factor or absorb B12. Also, it was my understanding that cyanocobalamin is not the human-active form
    and depletes the body of crucial methyl groups when being converted to
    methylcobalamin, the primary human-active form. Are you familiar with
    David Rainoshek, M.A.? He wrote a book called “B12 Exposed.” Based on
    his researching, B12 deficiency is widespread and mainly due to rampant digestive
    problems and a lack of intrinsic factor. The swallowed forms of
    supplementation aren’t going to do much if you can’t absorb it. Sublingual methylcobalamin and injections are more effective. The accurate test for B12 is the urinary MMA test, not the blood test. The blood test can show adequate levels when there really is a deficiency.

  • Michael Greger M.D.

    Also be sure to check out my associated blog post Vitamin B12: how much, how often?!

  • Welshwalker23

    I am ‘one of those Brits’
    Dr. Greger we have a Daily Vitamin D complex supplement which includes B12 and says 100% RDA. Is this enough for us?
    Thank you so much for this information, as your videos are normally USA based, it’s good to find some evidence relating to UK.

    • Rami Najjar – NF Moderator

      Dr. Greger actually has an entire series on vitamin b12. current RDa value are too low.

      Check out the video series here

      Click the link, view the video then on the right hand side click the video that is “Next up”

    • veggiedude

      Brits should not be worried about this – they have MARMITE!

  • Linda513

    I happened to have a blood test 2 months after I became vegan and my b12 was low – really low.  My doctor said there is no way it could have dropped that low in 2 months from a vegan diet, so I am fairly confident I was deficient before becoming a vegan, and I believe it was due to my acid reflux medication which prevents absorption of vitamins and minerals.  I think b12 should be routinely tested on everyone.

  • ladybug

    Dr. Greger, Are the high level B12 supplements safe for children?  I have 2500 mcg sublingual, and wonder if I can give them to my kids in addition to their multivitamin. Thanks so much!!

    • Toxins

      Yes, vitmain b12 is water soluble. It would be like taking too much vitamin c, the excess is simply urinated out.

  • “Whinny Vegans” WTF!!! That part was not needed. Pissed me off. I get my B12 elsewhere and I get plenty of it. So Suck Off!

  • are there any other Vitamins and other food adhesive that vegan needs ? what a bout eating one portion of meat once a week? 

  • guest

    Could you be more condescending?

  • Whiney vegans haha. I don’t like it when people get all pure and say we should follow natures design and not take supplements or whatever. If taking a supplement works, it works.

  • bakp

    hahaha! I am NOT part of the “whiny vegan” population, but I am a
    vegan..and very careful to take a B12 supplement! I was so interested
    as to the explanation about WHAT it was…where it came from, etc. I
    had a doctor recommend it years ago when I had wrist pain that could not
    be explained by tests…but the pain stopped when the sub lingual B12 was added by
    this wonderful physician! Since then I became vegan and my doctor said
    “now you REALLY need this B12 so do not forget!”…Now I know why and I
    thank you for this AMAZING website and all the information!!!!! Thank
    you thank you!!!

  • The fact that the study tests were serum (blood) B12 tests is a BIG red flag for me since such a test can result in false-positive or false-negative results!

    Without the study testing for MMA, homocysteine, holotranscobalamin, could it be that the actual B12 levels could actually have been LOWER?

  • Rob

    Does anyone see anything wrong with a diet where supplementation is absolutely needed to prevent death? What if you lived in the wild where you only ate what you could gather or kill? Could you gather enough food to sustain life?

    • The only supplement all vegans should take is B12. Out in the wild we would probably get enough B12 from our food and in our water as we would be living in a less sanitized environment. We and all the other creatures would be pooping everywhere basically. This would give the soil B12 which plants can absorb. I’m sure there are some extremist vegans here that would refuse to eat meat under any circumstance, but I would do what I had to do to survive. Would we be able to gather enough food as vegans? This depends. How many people are you sharing the land with? Where are you? I don’t see why I would adjust my diet, because I couldn’t do it in an environment I don’t and probably will never live in.

  • Niki Weaver

    Can you please clarify what a “normal” healthy level of B-12 is? I have been largely vegan for the last couple of years, but have not supplemented or had my B-12 tested in that time for a couple of reasons. Reason one is that I’m not a devout vegan. I eat a whole foods vegan diet the majority of the time, but I occasionally a small bit of animal products (seafood maybe once every few months, dairy maybe once every couple of months, and eggs from our own free range backyard chickens maybe once a month). I have those occasional spoils less and less as time passes so that is why I’ve been wondering about supplements. We drink fortified almond milk, but not in anywhere near the amounts you suggest. The second reason I have not supplemented is because the last time I had my blood work done, my b-12 levels were abnormally high. The lab work says it was a T4 FREE test and it lists my B-12 at 1117 while showing normal to be between 211-911 pg/mL. I’m curious since my B-12 was so high if it’s a bad idea to supplement, even as a vegan. I used to take a B-stress complex daily back then to help with lack of energy from fibromyalgia type symptoms (never diagnosed with it but have similar issues with chronic pain and tiredness), but after that test result I quit taking it and only take it once in a great while if I’m ill for a boost of energy. I was also still omni at the time of the test which was about 5 years ago. I’m hoping to get some new blood work done in the next year or so, but I’m unable to right now so I’m not sure how to handle this issue. Even eating a whole foods natural largely oprganic vegan diet, I still get sick frequently and don’t feel as well as I’d like to so I’m wondering if there something I’m missing. Thank you in advance for any insight you can give.

  • jerrylamos

    I was taking B12 supplement and B12 fish foods. Didn’t work. I started feeling poorly. I noticed blood test results MCV high and Hem low. Internet search B12 needs a protein from the stomach to be absorbed by the small intestine. Elderly men 78 may not make the protein. Solution sublingual under the tongue B12. 500 mcg daily after a month feeling better than the last 9 months. Liquid B 12 from GNC or B12 dots. I don’t know the maintenance dose. Blood test next month…oh, we eat for health and exercise most days.

  • K V Cash

    I haven’t seen one vegan who is B12 deficient and am really tired of seeing “b12 deficiency” with the word “vegan.” IF a vegan is eating a complete whole foods diet their OWN BODY will make b12 this is proven. So let’s get updated and end the b12 scare.

    • JamesKB

      In large intestine yes, but it cant be absorbed there. Elsewhere, small possibility, but very lacking in evidence.

  • Chloé Desharnais

    Hello doctor, thank you for you informational website. As a pregnant vegan woman, what is the daily amount of B12 supplements I should take, and is there any risk if I take too muck (if there is already 2,6 mcg in my prenatal vitamins, do I need another supplements) ? Thank you very much.

  • roscomac

    I recently had blood work done, and my B-12 was high – higher than the high end of normal – for a fasting test.

  • shelley

    why is this? Does this mean man is not meant to be vegan? I always thought that eggs were a natural food source but you speak against them for health. Our natural food source should contain every thing we need. Would love to know your thoughts on this.

    • Thea

      shelley: The problems with eggs far outweigh the benefits. Eating eggs for B12 is like drinking Coke for the water content. The bad of the coke far outweighs the good unless you just can’t get your water any other way.

      The idea of, “Our natural food source should contain every thing we need.” sounds so good in principle. However, the key concept of “natural” needs some expanding. Most humans no longer live in a natural world. B12 comes from bacteria and traditional sources such as water and veggies are unnaturally sanitized. That sanitizing is a good thing. It saves us from terrible diseases. But then we have to get our bacteria-by-product from somewhere. The safe, reliable source of B12 is a B12 supplement. Because we just don’t live in a natural world.

      Also keep in mind that *everyone* over 50 is supposed to take a B12 supplement regardless of their diet – because over a certain age, your body isn’t as efficient at absorbing B12. This is just another example of how the idea that our food should supply all our nutritional needs breaks down when you really think about it.

      You can learn a lot more about eggs and B12 from other pages on Check out the links that Dr. Greger included at the top of this page. i.e: “For some context…” Good luck.

    • Toxins

      In addition to what Thea said, please see Dr. Greger’s note on eggs

  • Deb Hanrahan

    I’ve been a vegetarian for years and went vegan back in April. After reading blogs like yours, I was so worried about a B12 deficiency. So in August, I started taking 5000 mcg methylcobalamin everyday. I just had my blood work done (I stopped taking the supplement a week before my blood was drawn) and my B12 level was 1996. No deficiency here. I think I need to scale back on the dosage.

  • Javier

    LabCorp Test – my blood works shows 799 pg/mL. Supplement if you need to. This should not even be a factor that makes people worried. Don’t skip on the b12 the fact that vegans are showing poor levels levels is crazy to me. It is not that hard to get good levels.

  • Tee

    Love your work Dr. Gregor that is why I am asking your opinion on this perspective.

  • Ana


  • Ana

    B12 supplements are not good for our health –they can be seen on exams, but they are NOT absorbed.That´s why I eat organic eggs.

  • Alexis

    Vegan here, I take a regular supplement. No need to call Vegans whiney though, you did a fine job making your point about vitamin deficiency. A lot of non-vegans say that Vegans don’t get enough protein, which is not the case. Have you ever heard of a real case of protein deficiency? Ha! It’s a joke. Beans, lentils, tofu, vegetables… a lot of us Vegans get more protein and vitamins than most non-vegans! Many Vegans may be lacking Vitamin B12, for which they should take a supplement, but many non-vegans are lacking many vitamins from eating too much starch, meat, and processed food. There has to be a balance. Thanks.

  • Kathie Jamison Cote

    We’ve been vegan for 23 years and my B12 levels are just fine! Yes we eat tons of plant foods.

    • Jeff

      I just eat dirt! :)

  • Jon Travis

    Was the “whiny vegans” comment necessary?

  • baggman744

    “In conclusion, the results from this study show that vegetarians and vegans have much lower concentrations of serum vitamin B12 but higher concentrations of folate in comparison to omnivores. Mean serum vitamin B12 was not associated with the duration of adherence to a vegetarian or vegan diet, which may indicate that mechanisms that maintain circulating concentrations of vitamin B12 are upregulated in vegetarians and vegans. Further research into the health effects of vitamin B12 deficiency and depletion in vegans and vegetarians is warranted and vegetarians and vegans should ensure a regular intake of sufficient vitamin B12 from fortified foods and/or supplements”

  • Bedreddin Ulusoy

    I myself am trying to follow a mostly plant based diet. But don’t these type of studies show that despite the other demonstrated benefits of plant based diets, they eventualy would lead to a major nutritional deficiency, i.e. Vit B12 deficiency, suggesting that they are actually not the best diets for humans? Or would we be getting vitamin B12 from other sources (bacteria in underwashed plants coming from the soil for instance) if we were living in more natural conditions?

  • Blair

    Dr. Greger, The study showed that more than half of these vegans were “deficient” in B12. But were any of them manifesting symptoms of ill health?How do we know how much B12 is necessary for good health?

  • Matthew Smith

    B12 deficiency is nearly identical to HIV infection. One would question if being Vegan could simulate HIV infection, or if there was a relationship. B12 levels are low among the HIV infected population.

  • Peter Olivero

    Perhaps it’s covered in the comments, but what purpose does sufficient B12 serve vs. insufficient?

    • NFModeratorKatie

      Hi Peter – Vitamin B12 helps keep the body’s nerve and blood cells healthy and helps make DNA. Vitamin B12 also helps prevent megaloblastic anemia.

  • Pole X

    Hi Dr. I recently bought spirulina capsules that say they are also a source of B12. I emailed the lab asking about the bio-availability of this B12 and they answered that since it comes in such high amount it is enough for the human body (320mcg every 10g). Is this true? Thanks!