Doctor's Note

Update: data heroically procured by Vesanto Melina suggests that the nutrition facts label of Red Star brand’s “vegetarian support formula” nutritional yeast is misleading, and that one may only get 0.9 mcg of vitamin B12 per teaspoon. So to serve as a sole source, one would have to consume 2 teaspoons three times a day (4 to 6 hours apart). The video was updated and re-recorded on July 14, 2012 to reflect this fact. Thank you, Vesanto!

Note that nutritional yeast doesn’t naturally contain B12—it has to be fortified with the vitamin. So, many formulations lack B12 completely. For example, while Red Star brand’s “vegetarian support formula” nutritional yeast is an excellent source of B12, their “elder support formula” doesn’t have any—which makes no sense, as the Institute of Medicine recommends everyone over age 50 supplement with B12. So, if you buy it in bulk and are relying on it for your B12, you may want to ask to see the package it came from, just to check to make sure it has B12 in it.

If you’d rather just take a supplement once a week, see yesterday’s video of the day: Cheapest Source of Vitamin B12. And for an explanation of why fortified foods and supplements are the preferred source, see the video before that: Safest Source of B12. And to put the whole B12 issue in perspective, see Vegan B12 Deficiency: Putting It into Perspective. And if you’re sick of learning about B12, there’s only one more video in this five-part series: New Vitamin B12 Test.

For more context, check out my associated blog post: Stool Size and Breast Cancer Risk.

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  • Michael Greger M.D.

    Note that nutritional yeast doesn’t naturally contain B12—it has to be fortified with the vitamin. So many formulations lack B12 completely. So for example, while Red Star brand’s “vegetarian support formula” nutritional yeast is an excellent source of B12, their “elder support formula” doesn’t have any (which makes no sense, as the Institute of Medicine recommends everyone over age 50 supplement with B12). So if you buy it in bulk and are relying on it for your B12, you may want to ask to see the package it came from just to check to make sure it has B12 in it. If you’d rather just take a supplement once a week, see yesterday’s video of the day, Cheapest Source of Vitamin B12. And for an explanation on why fortified foods and supplements are the preferred source, see the video before that, Safest Source of B12. And to put the whole B12 issue in perspective, see Vegan B12 Deficiency: Putting It into Perspective. And if you’re sick of learning about B12, there’s only one more video in this five-part series, and there’s always a thousand other topics to fall back on.

    • vegan gary

      Hi Michael

      I left this question some time back on your vegan epidemic video, but so far no response, so here it is again.

      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

      • Toxins

        Hello gary,

        Here is Dr. Greger’s response to the different b12 forms
        “cyanocobalamin (the inexpensive form) vs. methylcobalamin. Vitamin B12 supplements are so cheap to produce that supplement manufacturers try to come with all sorts of fancy ways to “add value” to products so they can make more money. The coral calcium scam is the classic example–how else can you charge $20 for a bottle of chalk? Likewise, unless you’re a smoker, have kidney failure, or base your diet around cassava root, cyanocobalamin should be fine. ”

        Gary, the reason b12 is healthy is because as vegans, b12 is non existent in our diet. Vitamin B12 is a byproduct of bacteria, it was once found in our water supply, and on the plant foods we eat. Because we now chlorinate our water (to avoid getting sick from other bugs) and because we dont ground pick our vegetables from the wild without washing them, the only available source is now from animal products. This is of course an unnatural setting. Similarly, iodine is no longer found in plant foods. This is why the government iodized salt, to help Americans get adequate iodine intake. Similarly still, we do not expose ourselves to adequate sunlight, and the UV rays of today are much more potent then they once were in our evolutionary past so vitamin D must be supplemented for optimal health.

        Humans have changed their environment, so sometimes supplements are necessary to achieve optimal health.

        b12 is also water soluble, (like vitamin c and other b vitamins) so you don’t risk imbalances or overdose.

        • vegan gary

          Hi Toxins

          What I am wanting to know is, is methyl just as effective, not whether it is more expensive. I have already got a substantial quantity of the stuff so I might as well use it if it just as good.

          I am still waiting for Michael to answer this and my other questions about how come taking B12 as a supplement doesn’t cause imbalances in the uptake of other B vitamins, when I thought this was one of the arguments against taking supplements: that it causes illness by causing imbalances in vitamin uptake. why also is it ok to take B12 isolated from other food (in other words as a supplement rather than in a food item) whereas taking folate in your bread so an unatural place for folate is bad for you? I think I know the answer to this in that food is a package deal and when we eat the folate in spinach for example we are getting fibre and other nutrients which may be important in some way to enable our body to utilise the folate. This is what I would like Dr Greger to talk about.

          • Toxins

            Vegan Gary,
            My above reply was meant to show you that both forms of vitamin b12 are equally effective and that manufacturers will try to make up claims for their product to make them more expensive.

            As for the other b vitamins, they are actually all water soluble so you cannot overdose on these vitamins either. That is why b12 so safe. Imbalances are not feasible. If folate is “added” to white bread it is the synthetic form, “folic acid”. Otherwise, folate is found naturally in wheat.


        • moonchasis

          toxins, i really like your thoughts on the B12 issue in regards to humans once having a measurable and viable/sustainable source of b12 via water, unwashed food. I am wondering if you are basing your theory on reputable studies, or is this a theory you have based on logic? i ask you this not to challenge you but to better understand the dynamics of the b12 issue. Logic tells me your statements are correct, but lots of people have claimed the same thing you have and no one ever shows reputable studies backing it up. i’d love to read a study claiming that humans sustained/sustain their b12 requirements in this manner. thanks so much for any clarity on this.

  • Thanks for remembering your YouTube homepage, Michael!! :-)

  • lisakskinner

    Dear Dr. Greger,
    At the beginning of this video the background is your 2011 recommendations for optimum nutrition. Where can we find this in a printable format? I would love to have a copy. Thanks so much for all your wonderful work!

  • Vera Springate

    Shown in this video recommendations’ outline for plant-based dieters is certainly very helpful to ensure that necessary nutritional requirements are met.  Would you please recommend sources to read on what’s vegan diet?  It seems definitions vary out there, and info overload doesn’t help either.  Do you have favorite recipe web sites?  Thanks.

    • Toxins

      Hello Vera,

      The best vegan diet is one that is entirely whole foods, plant based and unrefined. You want to try and eliminate white flour, white rice and remove free oils from your diet. You also want to keep it low fat and vary with the fruits and vegetables. I personally make my meals all complex carbohydrate based (brown rice, whole wheat pasta, sweet potatoes etc.) with other vegetables and spices.

      Here is a website with great whole foods plant based recipes.

      • Vera Springate

        Thanks Toxins.  Through which foods do you get your daily protein?  I’m dairy free and eat almost no animal protein.  Just legumes seems not doable stomach wise.  Don’t enjoy soy at all having grown up by the Arctic Circle (where pig’s lard makes the day :) )  Not enough protein – and too much fiber – is very possibly the reason why I’ve been having digestive issues.  

  • Shannon

    Hi Dr. Greger, can you give some specific recommendations for pregnancy supplementation specifically B12. Thank you very much!  Love this site!

    •  The recommended RDA is 2.6 mcg/d vs 2.4 mcg/d or an increase of about 8%. You can meet these by adjusting the amount of Vit B12 upward. It is important to work with you physicians as there are conditions which would warrant modification of these general recommendations. Best wishes.

  • Traxmom

    I am reading now that nutritional yeast is a neurotoxin, excitotoxin, almost identical to MSG, manufactured the same way, etc. Is this true? Should I banish the nutritional yeast from my pantry?

  • If I supplement with shots of b12, they go straight to blood stream, what would be my daily recommendation?

    • As a general rule for persons without disease I wouldn’t recommend shots. Most patients who need Vit B12 due to medical conditions can be managed with oral B12 as well. The dose varies depending on the condition. Shots can be used initially or if oral therapy is not adequate. You can get a sense for how complicated this is by viewing the Mayo Clinic website… If you have a medical condition it is important to work with your physicians to determine if you need B12 and the dose that works for you.

  • Guest

    Hi Dr. Greger! I love your site and think that you provide so much wonderful information. I have been taking vitamin code’s raw b-complex and am wondering if you or someone else can recommend another brand? I want to make sure that I am getting enough vitamin b12; the information on the back of the box says that 2 capsules contain 133 mcg of vitamin b12, which is supposedly 2217% of our daily value. I also bought Deva’s vegan sublingual b12, but then I noticed that it came with a California proposition 65 warning, so that’s no good. Can anyone recommend a good vitamin b12 supplement that is safe and effective? Thank you!

  • HealthyVegan

    Hi Dr. Greger! I’ve been taking MegaFood’s vegan b12 tablets and I am
    wondering if they are sufficient? I know that you recommend cobalamin
    and say that it can be found for as little as $2/year, but I have yet to
    find this (does anyone know where I can find this?). I stopped taking
    other vitamin b12 supplements because they had mannitol and other
    ingredients that I don’t want to consume. MegaFood’s b12 supplement
    comes from S. cerevisiae and I’m wondering if this yeast is another
    trusted source of vitamin b12? Thanks in advance for your help!

  • Julot Julott

    Is there the same limit from food B12, can we absorb 20µg of B12 if we eat oysters?

  • CristianAndres

    Hi Dr. Greger,

    I have read regarding the storage of VitamineB12 injections should be kept at a certain range of temperature and away from sunlight. I was wondering if this applies to supplements and/or fortified nutritional yeast?

    On the study that you showcased on athletes vs. nutritional yeast; your article stated that it is due to a specific fiber that helps our immune system. On this study was the nutritional yeast fortified or non-fortified? If so would the vitamin B12 play a role in the results? If so Couldn’t we just take a certain dose of vitamin b12 after excessive exercise and see the same results or equivalent?

    On a side note, I understand very well that the supplement business is no way regulated and it ends up being on trust without much evidence that the numbers/label are truly what is in the bottle. As in the case of your latest update regarding Red Star product; are there any brands or resources that you would recommend in this ocean filled of brands/manufactures of Fortified Nutritional yeast, B12 supplements and Vitamin D2.

  • C B

    Is too much nutritional yeast detrimental to our health? And how much is too much? What happens if we have way more than the daily recommendation of 2tbsps?? Is it dangerous to overconsume it on a daily basis?

    • Joseph Gonzales R.D.

      Hi, C.B. I am not sure how much is too much. In the studies from this video, anywhere from 3/4 of a teaspoon – 1 Tablespoon was consumed. Most of the fortified vitamins found in nutritional yeast are water soluble (B vitamins), so easier to excrete but I can’t imagine using more than 1-2 TBS per day. That seems like a good amount. Hope that helps.

      • C B

        Thank you very much! I will try to limit to 1-2tbsps per day until more studies have been made then! Thank you for answering!

  • Michelle

    I was wondering what the best way to get B3 is? I heard it can help
    prevent skin cancer and sun damage; is this true? I’d love to hear your
    take on this B vitamin (and others beside B12).

    • Joseph Gonzales R.D.

      B3 is niacin. It’s found in whole grains and other foods. Eating whole plant foods is the best way to get enough B3. Yes, B vitamins are so crucial and again they are found in many foods. B12 is another story and I recommend taking a supplement.

  • Tron

    i am taking 1000 mcg Cyanocobalamine in the morning, quite some time before eating for the first time.
    I read, that cyanide is transformed to thiocyanide in the body, which is a known goitrogen. So i wonder, if this won´t interfere with the iodine uptake during the day. More so, as the (round about) 20 mcg of cyanide (in mol) aren´t that much less than the maximum 200 mcg of iodine (in mol) i try to take during the day. So if there was a 1:1 blocking mechanism, nearly none of the iodine could fulfill its purpose.
    Thanks in advance.

  • Linda_vegan

    Dr Greger mentioned the fortified breakfast cereal can provide B12. I’m reading the nutrition label of Post Honey Bunches of Oats. It does provide 25% of B12 daily values per serving. However, the cereal has milk product: Whey, which is animal protein sources I want to eliminate. Should I stop consuming fortified cereal to avoid whey or keep consuming the cereal to get B12?

    • Joseph Gonzales R.D.

      Whole-grain cereals are best. I recommend getting B12 from a supplement in addition to what you get from fortified foods. B12 is super important. Adults needs roughly 2.4 micrograms per day. In supplement form it comes in higher doses. Here is a video on the cheapest source of B12.

    • The product that you mentioned contains honey. Honey is *not* vegan (comes from the bodies of bees) and IS an animal protein (bees *are* animals). Check out the article WHY HONEY IS NOT VEGAN & HAS NEVER BEEN VEGAN by the facebook page THE BLOODY DAIRY INDUSTRY.

      • Thea

        …Guest: It’s odd you would say that honey is “an animal protein” since honey is almost all carbohydrate. I’m not arguing that it comes from bees. I’m just saying that there is only the tiniest amounts of protein in honey. In fact, if you look at just a tablespoon of honey, there is so little protein that the nutrition label shows 0 g. Was that typo or …?

  • lindahappy

    Thanks for the b12 info but where can I purchase this B12 Dr Greger uses himself?

  • Paul Bashir

    Hi, I am desperately in need of a sound response to the following articles. These outline the potential deficiencies in vegans. Please respond at your earliest convenience and as always I would like to thank everybody who contributes to this forum because it is truly a magnificent thing. Thank you.

    “vegans typically fall short of the recommended daily intake for calcium (8, 45, 46).(…)The higher risk of bone fracture seen in vegans appears to be a consequence of a lower mean calcium intake.” “For a vegan, vitamin D status depends on both sun exposure and the intake of vitamin D-fortified foods. Those living in areas of the world without fortified foods would need to consume a vitamin D supplement.”
    “Compared with lactoovovegetarians and omnivores, vegans typically have lower plasma vitamin B-12 concentrations, higher prevalence of vitamin B-12 deficiency, and higher concentrations of plasma homocysteine (72).”

    “Vegans had dietary intakes lower than the average requirements of riboflavin, vitamin B-12, vitamin D, calcium, and selenium.”

    Mortality rates

    “mortality from ischemic heart disease was 20% lower in occasional meat eaters, 34% lower in people who ate fish but not meat, 34% lower in lactoovovegetarians, and 26% lower in vegans. There were no significant differences between vegetarians and nonvegetarians in mortality from cerebrovascular disease, stomach cancer, colorectal cancer, lung cancer, breast cancer, prostate cancer, or all other causes combined.”

    Vitamin B12 is not secreted by freshwater algae

    There is vitamin B12 in freshwater, but only tiny amounts.
    “A pond in the New York Botanical Gardens, rich in animal manure, had extremely high con- centrations of vitamin B12 (>lOO ng/liter) over a lo-month period (Robbins et al. 1950).”
    Based on a bioavailability of 50% an average person needs 4000ng a day.
    According to this report lake

    Very interesting article! Please make sure you read all of it. :)


    “The human digestion system differs from that of all other primates.” “Meat and other ASF provide all amino acids required for human protein synthesis; animal protein is also more bioavailable than plant protein (41,42).”

    • Joseph Gonzales R.D.

      Hi Paul, let me try to help.

      Like any diet, it’s important to obtain all of your nutrients, but that does not mean one cannot get enough on a vegan diet. The Academy of Nutrition and Dietetics has a position paper on vegan and vegetarian diets, which concluded theses diets can be healthful in every stage of life. They may also have major health advantages.

      B12 is super important. Adults needs roughly 2.4 micrograms per day. In supplement form it comes in higher doses. Here is a video on where to find the cheapest source of B12. Check out my
      comment on B12 for much more information!

      So many of Dr. Greger’s videos mention digestion. Plants offer all of the essential amino acids. There is no requirement for meat. It’s an interesting conversation and Dr. G and Brenda Davis RD (one of my favorite dietitians) cover the topic well: Will The Real Paleo Diet Please Stand Up?

  • cchare

    In the video he says the daily value of B12 is 6 micrograms. But in the same text it also says or 250 micrograms daily of supplemental cyanocobalamin. I don’t understand the discrepancy between 6 and 250.

  • Beatrice Lindsay

    Hi Dr Gregor,

    I take a daily supplement, but I also recently noted that a brand of beer (Erdinger) labels its alcohol-free product as a significant source of B12. Erdinger follows Bavarian purity laws (hence it can’t add any vitamins to the beer) and claims that the B12 naturally derives from microbial growth on the barley and wheat. Is this possible?

    Also, it appears that, in Canada at least, only non-alcoholic beers are required to provide nutritional information. So, are regular beers full of microbe-grown B12, but just aren’t labelled as such?



  • 111

    Hello everyone. I went to the doctor with really bad fatigue symptoms, and I asked him myself to include b12 in my tests. I am posting a question here because I can not feel I can trust the doctors and lab testing people in my area who insist that I start eating meat and having B12 shots. After a lot of internet and local research I decided to follow the sublingual treatment but I am not sure that my pharmacist is giving me the right directions either.

    Can you please let me know how much I should be taking and when to take the next test?

    I have been a vegan for 6 years and a vegetarian for 12 before that. Results B12:111, Folic:7.1, Fe: 132 (iron is usually low but I have been taking a lot of spirulina supplements lately), HCT:34.9% and MPV:12.5 fl and LDH 123 (135-214, do not know if it’s related in any way). My pharmacist gave me methyl B-12 1000 mcg and told me to take 1/day. Instead I am taking 2, 000 mcg/day after reading a relevant study and watching one of your interviews. Is this enough? It’ been 11 days now and I am not feeling better (well, maybe a bit but could be placebo + hope that I am not going to feel tired for the rest of my life).

    Also, is iron and folic acid going to drop now that I am taking the B12? Should I be taking supplements for this?

    Thank you for your time and all the work you are doing.

  • JKC

    I self-inject cyan B12, 2 ml, once per month. I am a 55 yo vegan. Any concerns or comments???

  • Joe Draper

    I’m really sorry to be a bother but I’m really confused. Dr Michael Greger says that only a small amount of B12 is absorbed, which makes sense, and so we need to eat much larger doses than our body actually requires. He said that we only need 4-7 micro grams (millionths of a gram) to keep our levels in check, but does that that mean we need about 250 micro grams orally every day? Because all my B12 tablets say they contain only 10 micro grams each. Do I need to take 1 of these, or more like 25?! please help me out. (the bottle says 10 (greek Mu) g, as in 10 micro grams)

    • Thea

      Joe Draper: I hope the section on B12 on the following page will help eliminate your confusion. Note that the amounts of B12 that Dr. Greger recommends changes dramatically depending on how frequently you are taking the supplement. This exponential line exists because of how much the body is able to absorb B12 at any one time. Check out:
      Does that help?

  • Heather kirchhofer

    How do I convert my dosage of liquid b12 from mcg to mL. I can’t figure out how much I need! My otter came with an mL dropper and I’m told I need 2.6mcg/day.

  • Plant Based Scott

    Hi Dr. Greger,

    Since B12 is produced by bacteria, is it possible that the bacteria in our intestines produce B12? And that eating a diet rich in fiber will support our gut bacteria, which would then produce B12? So we wouldn’t need to take a B12 supplement if we’re eating a fiber-rich diet?

    Thank you.

    • Thea

      Plant Based Scott: Great questions. Happily, Dr. Greger has covered this topic. The bottom line is that 1) yes, B12 is produced by bacteria in our gut. We know this because of an experiment where we gave people who were B12 deficient pills made out of their own poop and their B12 problem went away.

      2) the problem is that the bacteria which produces the B12 is so far down the digestive system that our bodies do not absorb it. So you still have to get your B12 from dietary sources.

      I was not able to find the video which explains this, but if you go through the B12 videos, eventually you would find it.

  • I’ve heard from certain people on internet forums that the sublingual type of methylcobalamin b12 supplements can cause a problem for people who have mercury fillings in their mouths. Is this true?

  • Jason Martin

    Some ppl on the internet claim sublingual methylcobalamin suppplements aren’t safe for people to use if they have mercury fillings. Is this true?

  • Protein Deficient

    If i will stop brushing my teeth,
    Can i live without b12 supplement then?
    I really hate to take supplements, drugs , toothpaste, or anything unnatural!
    None of our ancestors who lived on Plant Based Diet ever take any of those things.
    If we want to convince others to stop eating animal food,
    We need to encourage them, and stop force other to buy Unnatural Artificial Drugs,
    And when i means drugs i mean supplements, Supplements are nothing but a toxic drugs!

    When we use the argument, That dairy is unnatural, Because we never see other animal consumes the milk of other Species .
    We can’t claim this argument and at the same time take drugs or supplements,
    Other Animals NEVER takes drugs or supplements also!

    And our Ancestors never ate poop,
    And apes don’t eats poop ,
    Otherwise they weren’t survive due to cholera
    So this argument is not valid.
    Ours body certainly able to absorb the b12 from the bacteria by eating raw fruits and vegetables

    • Thea

      Protein Deficient: Non-human animals eat poop and dirty food and water. B12 comes from bacteria that live in the lower intestines of animals. (So, please do not stop brushing your teeth.) How do we know this? There are likely a number of ways, but one way was explained in a NutritionFacts video about an experiment where they took some B12 deficient vegans and fed them pills with their own poop inside. B12 problem was solved. Why did they have to take a pill? Because the bacteria that make the B12 live in the part of the intestine where we don’t absorb much nutrients.
      We live in an unnatural world where water is sterilized (that’s a good thing) and foods is washed (thank you) and we don’t typically eat poop (blessings to our culture). Food is a package deal. You can get some b12 from poop encrusted chicken (look up how contaminated our meat supply is), which comes with a vast supply of health hazards. Or you can get b12 from a perfectly safe and cheap supplement. It’s a no-brainer for me. Sometimes “natural” isn’t a good thing.
      Here is one of my favorite NutritionFacts articles on B12, which talks about putting the issue into perspective:
      Does this help?

    • Two quick thoughts….as a physician. We are living in a completely different world vs our ancestors and our food sources and processing are completely different. A quick analogy, if your car requires high test fuel you could use low octane, but the result would be poor efficiency or just plain failure to function. Neither is a good choice.

      However, I’d like to suggest that we can and regularly document nutritional deficiencies even in those eating great diets. So why not optimize. We and our ancestors indirectly get fecal contamination on a regular basis. Consider whats in your home if you wear your shoes into the house ( or you have young kids who are less than optimally sanitary or ……

      It’s not a simple drugs/supplement issue. In animal care,we regularly monitor and supplement many common well-kept animals even in organic settings. Considering the amazing variations of human expressions, genetically and epigenetically, and then expand this to the episome of our current planet and you can easily see why some level of optimization is probably warranted, by most individuals. Dr. Alan Kadish Moderator for Dr. Greger

    • Protein Deficient

      What about iodine?
      As far as i know ,Apes neither consumes salt or seaweed.
      Then why we must take this supplement?

  • Monika Hazelwood

    What about arsenic in B 12?

    • Thanks for your comment Monika.

      Any chance you can provide a reference or link to what you are referring to, I am not able to find anything. Are you referring to the action of Cyanocobalamin B12 vs Methylcobalamin B12?

  • healthy ian

    Why does my vitamin B12 supplement (cyanocobalamin) indicate that the 10 mcg in each tablet represents 167% of my daily recommended amount when Dr. Greger says that research shows we need 2,500 mcg / week or 357 mcg / day? I also notice my protein powder con taints B12 at 6 mcg and claims that is all I need per day.

    • Thea

      healthy ian: I don’t know the answer to your actual question. I thought I would point out one minor point so as to keep everyone on the same page. Dr. Greger recommends 250 mcg daily, not 357 according to the following page
      I hope someone answers your actual question. I’ll pass this onto our medical moderators to see if they have an idea.

      • healthy ian

        OK, so we are still talking about 20 B12 pills a day if the dosage is 10 mcg. Is the RDA for B12 really that far off?

        • Thea

          healthy ian: I don’t know what is going on. It’s been a long time since I reviewed the videos on this site covering B12. Hopefully someone else will be able to jump in with some insight.

        • Health Ian,

          You can easily get a 10 mcg dose in one pill. The RDA is so relative to “averages” that it’s not necessarily appropriate for the most people. I would suggest you do some testing if you’re wanting to get a better understanding of the level you need. You can get a cellular level via the testing at Spectracell labs, which uses your own cells or you could do an MMA test, not the b12 serum test ,which is inaccurate, or subjectively try one bottles worth of methyl B12 at a high dose and see note how you feel. You can easily get the levels you’re contemplating in one pill….see
          Dr. Alan Kadish Moderator for Dr. Greger

          • healthy ian

            Hi Alan, thanks for your response. So are you saying that 10 mcg a day is sufficient. I believe what I’m hearing from the Dr. and the earlier reply to my post is that I need 250 mcg per day or 2,000 mcg per week.

          • Healthy Ian,

            In terms of dose…’s person dependent and not a hard fast rule….. and a higher dose is rarely an issue. You will find that with all of the water soluble vitamins, including B-12, daily dosing is a more appropriate regime vs a per week or so unless your doing an injectable format. You want to maintain the levels not have large peaks and valleys in concentration. Dr. Alan Kadish Moderator for Dr. Greger

          • healthy ian

            Hi Alan,

            Thank you for your response. In one of Dr. Greger’s videos he seemed to be indicating that whether you take a large does once a week or a daily dose it doesn’t really matter with once a week clearly being the most convenient without any downside. Has his thinking / the science changed?

          • healthy ian

            Thanks for the link as well. checked it out but it looks like the B12 supplements they have are Methylcobalamin and from what I saw in Dr. Greger’s video post he suggests not going the Methly route and unequivocally recommends Cyanocobalamin. Has his recommendation changed?

          • Healthy Ian,

            I would highly recommend the methyl form, as cobalt excess from the cyanocobalamin can be an issue when used for long periods. The difference without the cobalt is slight in terms of the price not the effect and worth the difference…..I will check if his beliefs have changed.
            Dr. Alan Kadish Moderator for Dr. Greger

          • healthy ian

            Yes, please check, because he is very adamant in his video that cyanocobalamin is the way to go. What is the issue with cyano over time?

          • docbeccy

            Dr. Greger does recommend the cyanocobalamin form. That has not changed

    • docbeccy

      Here is a link to a more recent video Dr. Greger did indicating that recommended doses of B12 are in need of being updated.

  • Candace

    Please help!! When I became a strict plant-based dieter about 5 years ago I took the terrible advice of some members of the vegan community that I didn’t need to take b12. I did just fine for three years, but during pregnancy and nursing my son I became incredibly deficient without knowing it. I realized my error when my son was about a year old. I have been taking b12 ever since and am still breastfeeding my almost 2 year old son (who is in absolute perfect health) and my symptoms of a red, sore and bumpy tongue and fatigue have not gone away. I am desperate. I don’t know if I should have injections and if that is safe while breastfeeding? Please advice, thank you!! Thank you for all you do.

    ~Embarrassed B12-deficient vegan