hi I am greatly worried that people are taking over the dosage of their b12 I read that on here that there was thought a lead to cancer from to much b12 …people read to much and not fully understanding of what their bodies need every one is different … listen to your medical adviser they have been trained you might know your body but PA hides many illnesses..

22 Replies

  • Hi pugsly ,

    As far as I know there is currently no known harm of to much B12, what your body does not need it will just get rid of trough urine and faeces.

    Hydroxocobalamin (B!") is given in very large doses intravenously to combat smoke inhalation/ cyanide poisoning, so there is a lot of research on very high doses of B12 and no harmful effects are known, only things like acne type rash, temporarily raised blood pressure and discolouration of skin and urine, possible sensitivity to sunlight, some disturbance is sleep etc.

    But you are right, not everything is solved by B12, lots of other conditions are possible with same sort symptoms and getting a firm diagnosis, with the right treatment is the most important thing.

    To much folic acid may be harmful. To much B6 is known to be harmful.

    Kind regards,


  • Most of us are here because our medical advisers have demonstrated a degree of ignorance about our condition that leaves us with no option but to treat ourselves.

    Whilst it is true that there is a lot of overlap between symptoms of B12 deficiency and other conditions and having B12D doesn't rule out other things going on it is also true that having other conditions doesn't mean that B12D isn't also working it's evil in the background and making things worse

    There is a correlation between higher levels of cancer (and also with larger tumours) and receiving high doses of B12 but this is very different from being able to say that B12 supplementation leads to cancer - something that has never been established. In fact the most likely causal link between B12 and higher rates of cancer is likely to be the fact that people have been B12 deficient - something that is known to cause cancers because of the role B12 plays in healthy cell reproduction. The larger tumours are probably the result of B12 then meaning that the cancer cells also reproduce faster.

    I have heard of cases of People use B12 infusions to treat cancer.

    There is a link between some types of cancer and other kidney/liver problems and higher than normal levels of B12 but that has been identified in people who are not receiving any form of supplementation and relates to the effects of those particular cancers on the bodies mechanisms for absorbing and recycling B12.

  • Ideally Pugsley, we should be able to trust our medical advisers but, I'm afraid that medicine has become too test based. GPs are too busy to listen to symptoms, take history or get to the root of a problem, relying on expensive drugs, without which they cannot run their surgeries, and which often cause more problems.

    Many of them are also too arrogant to learn anything other than what they were taught and reluctant to read new research or guidelines, even when that person's quality of life, and even life, is at stake.

    I'm rather sceptical that too much B12 causes cancer. If a person is unable to absorb B12, it is likely that other important nutrients are not absorbed, making the body more vulnerable to disease.

    I'm reminded of what Jeff Bowles writes in his book on the miraculous effects of high doses of vitamin D3. Long ago, the pharmaceutical and government put out that vitamin D was dangerous in high doses and then marketed a drug for cancer which was, in effect, vitamin D !

  • B12 doesn't cause cancer, it can just make an existing tumour grow a bit, depending on other factors aswell. This is because b12 is a major playe r in cell reproduction and off course tumours are reproducing rapidly. You need high doses of b12 as you only absorb around 1% of b12 through you digestive tract.

  • I would love to stop self -medicating and rely entirely on my doctor and agree that it is very important to listen to your doctor/medical practioner.

    However, it's a two way process and doctors should listen to their patients. I tried desperately to get my doctor to listen to me and requested trials of B12 treatment. I pointed out evidence in my medical history and gave them an extensive list of symptoms which closely match those of PA or B12 deficiency.

    In the end I became scared of how ill and weak I had become and decided to self treat.

    I did everything humanly possible to get treatment from my doctor and failed.

    I have spoken to the PAS and was told that the sort of symptoms I was experiencing are found in PA (Pernicious Anaemia).

    Sally Pacholok's book "Could It Be B12" mentions potential links between low B12and cancer.

  • make a double appointment with a different Dr in the pratice go armed with your findings and say… putting them on the spot I understand that you disagree with how 1st I feel and you are allowed your appinion but I would like to be sent to a concultant who deal with this complaint as I know how ill i feel and how low I get so please will you refer me today Do ;nt take no for a answer , but self medicating is not the answer

  • If I listened to my medical advisors, Pugsly - ALL of them, including the highly paid consultants - I'd never have got any B12 at all, still be taking megadoses of dangerous anticonvulsants, be deeply depressed and lying in a stupor on the sofa, and be in a great deal of pain. I'd have NO idea that I had any kind of B12 deficiency, or that I was also IgA deficient and suffered from hypothyroidism.

    Forgive my complete disagreement, but the medical advisors you imagine do not exist. The real ones are all very fallible, undereducated, short on time and largely uncaring. And if you think B12 causes cancer I would suggest you may be reading too little rather than too much.

  • Sorry but I must disagree here in the vale of glamorgan we have one of the best Dr SURGERYS they are polite listen and ready to help I was the practise first patient 68 years ago when my mother delivered me. I had my daughter at home with the same Dr;s she was born spina bifida the Dr traveled in dreadful weather to get her to hospital and 13months later on her coming of home they were there and know at 42 she is awaiting a transplant and she gets the best treatment .there is not one person here in the village can complain so again talk to your Dr but if you are happy to self medicate you and you alone have no one to blame

  • That's a charming story Pugsly, and it warms my heart to see such a good example of conscientious doctoring, but, with all due respect, it doesn't change the fact that my story, which is VERY different from yours, is by far the most common.

    NHS doctors don't have the time to do the investigations they need to. I presented with trigeminal neuralgia - nothing to do with B12 deficiency, according to the text books - and so they did nothing but give me strong medications. Had I not done my own research I would have not only stayed sick but got sicker. Right now I am STILL fighting my doctor - who is a decent doctor by modern standards - to have my illness considered as a symptom of a bigger picture.

    Again, with all due respect, spina bifida is not a mystery disease. Your doctor had protocols and followed them well. That is admirable and decent. However, not everyone presents such a clear-cut case; it is then you are on your own, or worse, fighting to be taken seriously.

    I am perfectly prepared to believe you have a fabulous relationship with your doctor, but you must appreciate you are one isolated example, not a representative of patients at large.

  • Sorry NO the whole village have the same one on one we have 3 groups and the Dr;s move around to each village the nurses the care nurses are all there to help, its the way it is run we have a very large Army/ RAF base where the families used to be housed but it is know used as a cool off centre on coming back from different war/s oversea trips all these families are given the same treatment … may be one should go into the Dr;s and ask his advise not tell them what it is after all he spent years training it could be putting his back up

  • So, you sit in on every doctor's visit in your area, Pugsly? Or do you just poll everyone who comes out the doctors? Or perhaps you are psychic and know what is said in everyone's trips to the doctors? Or are the surgeries bugged and the village has an excellent grapevine gossip system? Because those are the only ways you could possibly speak for an entire area's experience of health care.

    Even if your area has exemplary health care - and one wonders how they manage that under the same constraints as the rest of the NHS - you still couldn't speak with authority on everyone's experience. You are merely assuming this to be the case, and it simply isn't, no matter how much you want to believe it.

    But then you also seem to be assuming that everyone who is not doing exactly what you do is self-treating (I don't), and that we all tell our docs "what it is" and "put their backs up" (I don't do that either; after all, if I knew what "it" was I wouldn't need his help, would I?)

    The only thing I can suggest is you take a look at this article from Dr Malcolm Kendrick - a bona fide good doctor, just like the ones you know - talking about how badly thyroid patients are treated. Interestingly, he's entitled it "Treating thyroid patients like children" - something you seem to be advocating, with your belief that medicine is some kind of patriarchy, with kindly avuncular doctors taking care of us all out of love, and who we should all trust implicitly and never question.


    It strikes me as odd, given your surety that doctors are all well-educated and efficient, that what he talks about here could possibly be happening in your world of perfect medicine. Now does this mean he's a raging liar, or might you just be wrong?

  • you are being plain rude And trying to say things that were not said I believe in giving praise where it is deserved, mind if this is your attude to me no wonder your GP can;t be bothered with you, best stick to your own medication

  • I'm not being rude, Pugsly, I'm querying how you can possibly speak on behalf of a whole area. And it wasn't me who claimed that, you claimed it for yourself. If you don't want people to ask you how you know about everyone else's health care, don't assert that you do. If you haven't been appointed spokesperson for your area, don't set yourself up as one. Perhaps, most importantly, don't post inflammatory comments that are intended purely to tell people off for perceived infractions of the way you feel they should run their own health-care. Particularly if you can't substantiate them with facts, only conjecture and ill-thought out opinions.

    Lastly, as I have already told you, I don't self-medicate. Perhaps people might consider it rude to continually assert I do. Unless, of course, you believe that I am also a liar, like Dr Kendrick?

  • Oh you are SO lucky to have good surgeries where you live, but I do feel you are not understanding what others are saying. I have seen every gp in my surgery , and have got nowhere, particularly on B12 and menopause. All my surgery want to do is palm me off with antidepressants ! Which I constantly refuse. Our surgery give 5 mins per visit and contradict each other constantly . This country are rules by test ranges not symptoms even if you are right low on the range

    We are not lying when we say we are not listened to

  • Hi Pugsley. I'm really glad that you are having really good treatment in your surgery and village and are surrounded by good, caring people.

    I too had a caring and efficient doctor, had both my children at home with the same wonderful midwife, but that was over forty years ago, when medicine was an art as well as a science !

    I cannot fault my present GP in many ways and her efforts to do her best in today's test and drug based medicine but, with thyroid disease and B12 deficiency, the tendency is to treat us all as hysterical hypochondriacs, who haven't a clue what we are feeling. Their ignorance (combined with the influence of BigPharma), adherence to flawed and unreliable tests and inability to get to the root of illness means that thousands of people are condemned to half a life at best or eventual dementia and death. So no - I definitely will not listen. I shall continue to take responsibility for my own health and thank God for sites like this and Thyroid UK

  • I have read (Dutch national Health Council) that there is absolutely no danger at all from huge doses of B12 It also said that often patients with liver diseases e.g. cancer often have extremely high amounts of B12 in their blood because the liver is unable to store B12,and it ends up in the blood. I can assure you that G.Ps in the U.K. have no understanding of B12 deficiency. You see "Big Pharma " is not involved--- No research as no profit because B12 cannot be patented. Our GPs are mostly in bed with "Big Pharma"

  • hi

    It is true self treatment can be dangerous, i have pernicious anemia and hashis, in both cases the doctors have left me with no quality of life, only by self medicating have i been able to get through the past 3yrs. i dont know what ypur story is but until you have been as desperate as myself and others on this forum you probably wouldnt understand. Thank you though for potassium info i will look it up

  • The reason i'm against self medicating is I have nearly lost my life have needed twice during the birth of both my children transfusion, then was put on B12 for weekly dose started to feel so much more alive then it brought on problems, then my Dr gave me a diet that was used in Holland drinking full cream milk eating chocolate oranges but small amounts of exercise but the tiredness started coming back was in the usa went to a well womens clinic they advised these tablets and powerders all agreed by medical proffenernals i became so ill on returning home I had server kidney problems ..yes i read every thing I was shown but nothing went as far as saying what could happen if you surrfered with a list of things and no one knowns this but your Dr and he is there to advise you think…… it would be so easy for the Dr's to just give what you want just to get rid of you they are helping but maybe not as quick as you want…all i ask please becareful xp

  • Its great you have so much trust in doctors, i dont., but i agree you have to be very careful when self medicating but i have no choice

    Wish you well


  • yes you always have a choice …you alone make the decissions how to take care of your body, if you feel so pressured go private it would work out no more expencive than all you pay for on internet

  • Can i ask you a personal question do you have pa or thyroid problemswhat is your health status

  • Why are you so obsessed withpeople self medicating? If ypu think its damgerous DONT DO IT thats youre choicewe are all adults on this forum we know exactly how we feel, how our doctots are not giving us the help we need and the risks of self medication. Dont presume you know whats best for anyone but ypu and if you dont need to self medicate good for you but pthers do and they ae as careful as they can be!

You may also like...