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Pernicious Anaemia Society
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B12 deficiency...Super Confusing :(

Hi guys, I had posted earlier about my low b12 levels and how I have been supplementing with sublingual strips (2000 mcg, b12, b6 and folate) and jarrows b12 (5000 mcg) since the past few months. I recently got a b12 serum test done and the results were in the 900-1000 range but that didn't stop me from supplementing. Recently I have started experiencing fatigue, muscle cramps, body ache, dizziness and confusion. I thought it might again be b12 deficiency and tried a different b12 brand - vegansafe, which is considered to be highly potent with both adeno and methyl, but no luck so far with the fatigue and muscle cramps. My question to all of you is could excess b12 cause the same symptoms as low b12? I have read a few posts as well as seen a video on YouTube where individuals were complaining of similar symptoms owing to a high b12 level. Should I discontinue the supplements or does excess b12 leads to deficiency in other minerals like magnesium which might be contributing to the weakness/muscle cramps? My GP couldn't care less and hence turning to you guys for help/insights.

28 Replies

You need to know if you have Pernicious Anaemia . You need to have a blood test to find out if you have the antibodies to the Intrinsic factor which prevent you from absorbing vitamin B12. Unfortunately this test is unreliable and is is quite common to show up negative , but still suffer from P A. That can be your first hurdle ! I did what you are doing,and supplemented with patches , sub lingual lozenges and nose spray - to no avail . I had the test which proved positive . So I now have to be treated with injections of B12 . This is how most PA patients can absorp B12 .

The next hurdle is the medical profession who are very ignorant about PA ! You may find it difficult to get the correct treatment . I have Then you have to take matters into your own hands and self-inject .( I have to obtain B 12 ampoules from Germany) I do and my health has changed dramatically , except for one small problem which has become irreversible because diagnosis and treatment was very delayed .

What you also need to do is buy the informative books on Pernicious Anaemia by the founder of this society Martyn Hooper (Amazon) and a book by Sally Patchalok called Could it be B 12? You also need to have the scientific papers on all aspects of this disease . One of our members , fbirder will send you links to these important papers I'm sure . Because you have supplemented the doctors will think that your b12 is fine , when it isn't . Intramuscular or sub-cutaneous injection is the answer if you do have P. A . This is the start of a journey for you . Sorry I have to dash now , but I'm sure other members will be in touch with you . YOU HAVE COME TO THE RIGHT PLACE ! I wish you all the best !


Excellent summary Wedgewood!

I'd like to add also, Dlonelyguy, that too much B12 is not harmful. Many studies show this and there have been posts on here which have links/footnotes to the science that backs that up my statement. I believe it was Clivealive who posted a very thorough summary of the non toxic effects of very high serum levels of b12. I can look through older posts and copy and paste it to you, but give me a few days! :-) I haven't seen the posts/Youtube videos about the symptoms being the same for deficiency as they are for high serum levels, but I self inject 800mcgs. every other day and on my off days take up to 10 x 5000mcgs sublingual lozenges. This regimen has made my symptoms of fatigue, unbalanced gait, dizziness, neurological eye problems, sure tongue, mouth ulcers, etc. go away.

Wedgewood has given some excellent suggestions going forward.

Take care.:-)


Thank you Ndodge. I want to get clarity here. When you talk about off day do you mean in between injections you then take oral tablets? Second question which vitamin B12 are you using? Cyanocobalamin or Hydroxycobalamin or Methylcobalamin?


Hi Mangi36,

I take an IM shot every other day and the days in between in which I get no shot I take sublingual methylcobalamin. I use Superior Source "No Shot" brand - I found a higher dose one at 10,000 mcgs. I take 3 or 4 of those on my off or 'no shot' days.

I get them at Swanson's online vitamin website which I believe is an international website.

Good luck! :)


Thank you very much.


My Pleasure- hope the sublinguals work well for you :)


I placed an order of sublinguals and orals. I will compare the 2. From Swansons.

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Let me know your results, thanks!:)


I use 5000mcg it gives me cramps. Body ache, backache but strength improved. My vision improved, balance improved. Noice intolerance improved.




I have PA. I supplement with sublinguals, but i inject several times per week. To diagnose PA you do need the intrinsic Factor antibody blood test. It does take a while to feel normal even with injections. It's been over two years of treatment and i'm just beginning to feel like my old self enetgy wise, however, in some ways i am forever changed. Good luck, keep hopeful....it gets better.

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I forgot to say that vitamin B9(folate ) is also important for you . So you should be eating plenty of green leafy vegetables or supplementing B9.


Thanks a ton guys for the replies! This surely helps. Also hypothetically in case a person does not need b12, will supplementation still not hurt? Also do you guys take magnesium and iron supplements along with d b12 ones?? I had read a few posts where people have suggested that b12 supplementation might lower your iron and magnesium levels.


I took iron supplements when my ferritin level was 30ng/ml and I was iron anemic but as soon as my levels were normal, which is around 70-80 ng/ml., I stopped taking it as per my doctors orders. You can get too much iron and that is not good. If you are not anemic/deficient, there is no reason to take iron.

A B complex, is good, but you can take too much B6 if you take it by itself. I think 10mgs a day is what is in most B complexes. It is better to take B vitamins in a complex anyway.

You can try magnesium supplements - might help the muscle aches.

I don't think B12 "lowers" iron but that a healthy iron situation is needed for good uptake of B12 by the cells. I'm not sure how magnesium is connected in the processing of B12, but there are other more knowledgeable people on this site who do know! :)

As far as taking B12 or any of the B's, the body will excrete out what it doesn't need/use. as B vitamins are water soluble. That's why it is not harmful to take a lot of B12. It would be of a waste of money to take it if you don't need it rather than unsafe for the body.

I hope you get it all sorted out, Dlonelyguy! I am not a medical professional, just someone who has struggled to get all my numbers good again!


Don't forget that with B12 supplementation, your need for potassium will increase. Too low, and it will cause cramps. Ditto magnesium.


I think bananas and spinach are high K.


In answer to your question - high levels of B12 in serum can cause the same symptoms as low levels - this is known as functional deficiency. This is because it isn't the amount of B12 in your blood that counts it is what is going on at the cell level. Of course, if there isn't much B12 in your blood then there isn't going to be much getting through to your cells but that isn't the whole story.

There doesn't seem to be much out there about treating a functional deficiency caused by treating a B12 deficiency but all I've been able to come across points to keeping levels extremely high so that enough B12 actually gets through to cells and once it falls below that level then the functional B12 deficiency starts to kick in.

My personal experience (and observation of my mother, brother and aunt) would be that for some individuals the normal treatment with injections can actually kick off some quite significant problems with functional deficiency. I got a lot worse after treatment started and for the year after and it was only when I started treating myself with extremely high doses of B12 that things actually started to get better for me. I don't rely upon injection but use a variety of forms of B12 and mix nasal spray, sublingual and the occasional shot (2-4 times a week - but some weeks I won't do any - but it is a convenient way of making sure that the dose really has got inside me).

My brother was showing signs of B12 deficiency but was a bit wary and also has MODY diabetes (I didn't inherit the gene) and had enough problems with getting his diabetes treated properly that I don't think he would have been prepared to go through trying to get a B12 absorption problem diagnosed. He does regard me as a bit of a fanatic and I am quite prepared to admit that I could bore for England when it comes to B12. However, he also recognises the impact correcting my B12 deficiency has had has been extremely significant, but it was overhearing somebody in a restaurant talking to her friends about the impact that her B12 shots had on her that got him interested in trying a nasal spray. I was a bit stunned to find out (after my own experience of needing 3-4 x what it said on the tin that he actually found that he only needed to use it sporadically). Things were pretty similar with my aunt (mother's sister) who started using .5mg a day of the nasal spray and reported that it helped with her energy levels and also the mysterious dizziness that had baffled her GP but sounded rather familiar to me.

My mother had an extremely difficult year last year - with a lot of confusion, infections and cancer of the womb. She ended up in hospital with a massive hypo after the local district nurse took on managing her insulin and ended up in hospital - where she stayed for treatment of one of the infections. She'd had the dementia blood series done the week before that happened as I'd lost her 2x and had to call out hospital security when we went for an appointment where the cancer was diagnosed. She had a second B12 test done when she was in the cottage hospital for assessment after the hypo and ear infection had been dealt with. It showed a significant drop so her GP put her on loading doses ... I didn't twig until I was looking through her medical notes a few days later because her behaviour was getting very odd and she was just falling asleep on her feet all the time ... and realised at that point that she had the same problem I did and so she's now using a nasal spray 2-3 times a day - with support of a carer as to be honest I think the deficiency went on for so long that she now has a degree of dementia.

Notice from your other posts that you have had loading doses so may be that you are in the same boat as I am.

When you say that the muscle cramps and fatigue are still there does that mean that other symptoms have improved?

It may be that there is more than B12 going on - lots of things can cause muscle cramps - including other deficiencies - and similar with the fatigue.

Macrocytosis can cause fatigue - as macrocytosis makes your red blood cells less efficient at transporting oxygen to cells where it is needed. Macrocytosis is caused by insufficient B12 being available in bone marrow to ensure that new red blood cells delevop there properly. It will only be corrected as your old red blood cells die and are replaced by new ones. As red blood cells live for around 120 days this is obviously going to several months to correct - though it sounds from early post as if you didn't have macrocytosis - so not likely to be an issue.

Please note - magnesium supplementation causes diarrhoea in significant numbers of people - main why the EFSA (European Food Standards Agency) could not set an upper daily limit for supplementation.

Low potassium is a particular risk if you have macrocytosis so may not be an issue if you don't. It is very easy to overdose on potassium - extremely unpleasant and potentially life threatening. Unlikely you would be able to overdose with from dietary sources but ...


Thanks a ton for that elaborate answer Gambit! This is a lot of information and provides a reassurance that I am not alone. Well my doubt stems from the fact that I do not think that I was severely deficient in b12 in the first place. Yes I had occasional memory relapses but that was it. No tingling/burning, balance/coordination issues etc. Though my ibs and hair fall improved significantly after starting the sublingual. Yesterday out of curiosity I had 6 bananas and it really helped. My energy levels got better, the muscle cramps went away and I felt great. Can potassium and magnesium deficiency mimic b12 symptoms of tingling and burning hands and feet and dizziness/confusion? I personally feel that I am having too much b12 on a daily basis without considering the fact that it might lead to deficiencies in other minerals/vitamins and might not be beneficial to the body. To be very honest I started the b12 treatment thinking it will help me with my word finding and slurred speech issues and now I believe that a lot of other ailments can contribute to that. To sum up...really confused and I'll tell you one interesting thing: the best thing about internet is that you just need to type a symptom and a potential cause, it is flooded with articles which will provide a link between the two :).


link to symptoms of low potassium


which do include cramps so could be that

The symptoms of B12 overlap with other conditions all over the place - including other vitamin defciencies.

Glad that the bananas helped but 6 a day might be a bit much on an on-going basis.

You might find this useful in relation to other minerals and vitamins - EFSA guide on upper limits for vitamins and minerals - each section gives quite a good precis of the symptoms of deficiency and problems with supplementation in arriving at a recommended upper limit.


it's quite old and it might be worth checking the site for any amendments as they do regularly review the advice


I can't thank you enough for all the help Gambit! I generally don't say this often, but you truly are a gem of a person! I sincerely hope that you keep on shining the light on many lost souls like me.


Gambit62, about your comment on potassium, you might be interested to read this post on Dr Malcolm Kendrick's blog:


It seems that it's quite difficult to achieve a lethal level of K via the oral route, which was news to me. I now take as much K gluconate powder, 2-4g daily, as I feel I need. The same symptoms always seem to appear when I'm low, and disappear when I supplement. Of course, the low K may be a consequence of injecting B12 daily.


Thanks Hillwoman - very interesting


Just gone back and looked at the EFSA recommendations on potassium

efsa.europa.eu/sites/defaul... p409

looks like some forms may be unsuitable - mentions potasium chloride and it probably isn't advisable if you have renal problems or if you are on some medications for high blood pressure

The article you quote mentions supplementing with potassium citrate or potassium bicarbonate.


Thanks, Gambit. I tend to avoid potassium chloride, but I've tried citrate successfully.

Edit: thanks for that link, btw.


Hi Dlonelyguy,

Sorry this took so long to get this info to you- but here it is- hope it is helpful! It was written and posted by Clivealive, a member of this forum and I'm passing it on to you:

The whole article reads as follows but if you just want to scroll down to the "Conclusion" I won't blame you:

"Treatment with high dose vitamin B12 been shown to be safe for more than 50 years

Out of fear of overdosing vitamin B12, treatment is often reduced to below the frequency that is needed by the patient, or, even worse, treatment is stopped completely.

As a result, symptoms can reoccur again and again and even become irreversible.

It is very clear this fear of overdosing is based on a misunderstanding. For over 60 years high dose vitamin B12 treatment has been used without any signs of the danger of an overdose.

The Dutch National Health Counsel and the Regional Disciplinary Medical Board of Eindhoven have stated clearly that vitamin B12 is non-toxic.

Clinical research and the treatment for cyanide poisoning have shown that even extremely high doses of vitamin B12 and the serum values that go with it are harmless.

A decennia long history of safe treatment

In 1926 it was discovered that patients with pernicious anaemia could be saved from a certain death by eating a pound of raw liver a day. More than 20 years later the substance that was responsible for that was isolated from liver extract: vitamin B12 or cobalamin. Since then numerous patients have been treated with high dose vitamin B12 worldwide. Usually per injection and often lifelong, as a deficiency is mostly caused by an irreversible absorption disorder. In all that time harmful effects have never been shown from overdose. No single case has been found in medical literature in the past 60 years.

No maximum dose

The Dutch National Health Council therefore decided not to determine a safe upper intake level for vitamin B12. In their report from 2003 “Voedingsnormen: vitamine B6, foliumzuur en vitamine B12” the council joined expert commissions from the American Institute of Medicine and the Scientific Committee for Human Food from the European Union, who had already reported 3 years earlier that toxicity from high dose vitamin B12 poses no real danger.1

Of course, like with any medical treatment, side effects can occur. Acne, eczema and itching seldom occur and very rarely anaphylactic shock. Changing brands of vitamin B12, forms of B12 (cyanocobalamin vs hydroxocobalamin), or switching from injections to tablets can be a solution in those (rare) cases.

Misunderstandings about blood and reference values

Yet often physicians reduce injections or even stop treatment altogether out of fear of overdosing B12. The result is that many patients are left with recurring or lasting symptoms, which could be relieved by more frequent injections. After an injection the serum B12 value rises quickly, well above the upper reference value (on average 150-700 pmol/L), followed by a slow decrease. Apparently the underlying thought is that it is necessary to keep the value between the (upper and lower) reference values. However the blood level of serum B12 rises regardless of therapeutic effectiveness.2

A high serum B12 value does not mean that symptoms are treated sufficiently. This presumption can have damaging effects for patients with neurological symptoms, which can become irreversible with insufficient treatment.

Treatment based on symptoms instead of blood values

The recommended treatment in the Netherlands consists of a hydroxocobalamin injection of 1mg every two months, after an initial loading dose of 10 injections in 5 to 10 weeks.3

No reference is made to the serum value or a danger of overdosing, unlike for instance in case of a vitamin D or A deficiency. The lack of danger of an overdose is further underlined by the advice to treat patients with neurological involvement with two injections a week for up to two years, if necessary. This also emphasizes that symptoms and not blood values should be used as a guideline. If serum values were decisive, even patients with neurological involvement could suffice with the maintenance dose of one injection every two months after the initial loading dose.

Elevated serum B12 values in serious conditions

Maybe the concern for a possible overdose is caused by the knowledge that some life-threatening diseases can be accompanied by a strong increase in the B12 blood value, in some cases to even 30 times the upper reference value.4

In blood diseases like leukemia, polycythemia vera and hypereosinophylic syndrome, the cause is often an enhanced production of the transport protein haptocorrin, to which most of the circulating B12 in blood is bound.

In liver diseases such as acute hepatitis, live cirrhosis and liver cancer, elevated B12 values are often found because the liver is no longer capable of storing vitamin B12.

Elevated B12 values are always cause for further testing, but of course, to the contrary, it cannot be concluded that elevated levels after B12 injections leads to serious disease.

Scientific research

Scientific literature offers numerous examples from which it can be concluded that treatment with high dose B12 up to very high serum values is no cause for concern.

In the treatment of children with an inborn error in the production of transcobalamin II, the binding protein that transports B12 to the cells, serum values are kept at levels of 10 000 pg/ml (about 7 400 pmol/L) without any side-effects.5

Japanese research from 1994 into the effects of B12 therapy in patients with multiple sclerosis shows that a daily tablet with 60 mg methylcobalamin during six months is non-toxic. Half of the patients even started with two weeks of daily 5 mg B12 injections straight into the blood. 6

In the fifties, when chemotherapy wasn’t available yet, children with neuroblastoma (a tumour of the autonomous nervous-system) received 1 mg B12 injections every other day during 2 to 3 years in a London children’s hospital. From 1957 the dose was adjusted to 1 mg per 7 kilograms of body-weight. In the majority of patients the tumour disappeared wholly or partially and the chance of survival was considerably increased.7

In 1999 in Japan, kidney dialysis patients with polyneuropathy, received 0.5 mg methylcobalamin 3 times a week intravenously for 6 months. Because of lack of renal clearance, serum values rose to more than a hundredfold from 422 pmol/L on average to 54 000 pmol/L, with 67 000 pmol/L as highest value, without side-effects. 8

Also in Japan, in 2007, patients with the incurable neurodegenerative disease ALS (Lou Gehrig’s disease) received daily injections with 25 mg methylcobalamin for 4 weeks, followed by daily injections of 50 mg intravenously, followed by 50 mg a week. In the long term, treated patients survived for longer because of this, than did untreated patients.9

Megadoses B12 as lifesaving antidote

The safety of vitamin B12 treatment is further illustrated by the decennia long use of hydroxocobalamin as an antidote for cyanide poisoning, often caused by smoke inhalation. In the Netherlands ambulances, fire departments and emergency rooms have the Cyanokit at their disposal. In life threatening situations 5 mg hydroxocobalamin is given intravenously within 15 minutes, an amount that corresponds with 5 000 injections of 1 mg B12.10 Hydroxocobalamin reacts in the body with cyanide, and forms cyanocobalamin, which is excreted in urine.The serum value of B12 can rise to an average of 560 000 000 pmol/L within 50 minutes.11 If necessary this treatment is repeated within several hours, making the total dose 10 grams. The side effects that occur, like reddening of the skin and urine and changes in heart rate and blood pressure are temporary and harmless. In short: 10 000 injections a day are still not enough for an overdose of vitamin B12.

Regional Disciplinary Medical Board: vitamin B12 cannot be overdosed

In 2009, the Regional Disciplinary Medical Board in Eindhoven stated very clearly that an overdose is not possible: “There can be no question of an overdose of hydroxocobalamin, as the excess is excreted in urine by the kidneys and therefore cannot accumulate in the body.12 The Medical Board ruled against a patient who claimed his deteriorating health was due to the continued treatment with B12 injections. The patient received monthly injections for 10 years. The physician was not rebuked because the patient was treated according to guidelines.


A vitamin B12 deficiency can cause many different symptoms, among which are serious neurological problems. The treatment with high dose B12 injections is not only completely safe but fortunately also very effective. With the right treatment patients can recover completely. Starting straight away with treatment is essential, as is the continuing treatment in order to give the body enough B12 to fully recover. Therefore it is essential that patients are no longer exposed to the real danger of irreversible symptoms because of the imaginary fear of overdosing.


1. Voedingsnormen: vitamine B6, foliumzuur en vitamine B12. (Nutritional standards: vitamin B6, folic acid, vitamin B12) Gezondheidsraad.Publicatienr. 2003/04, Gezondheidsraad, (Dutch National Health Counsel) Den Haag 2003:130-31

2. How I treat cobalamin (vitamin B12) deficiency. Carmel R. Blood 2008;112: 2214-21

3. College voor Zorgverzekeringen. Farmacotherapeutisch Kompas. CVZ, (pharmaceutical reference book) Amstelveen 2011

4. De betekenis van een te hoge cobalamineconcentratie in het bloed. (the significance of a high cobalaminconcentration in blood) Ermens AAM, Vlasveld LTh, Van Marion-Kievit JA, Lensen CJPA, Lindemans J. NTvG 2002;146:459-64

5. Inherited disorders of folate and cobalamin transport and metabolism. FentonWA, Rosenblatt DS. In: Stanbury JB ea. (eds). Online Metabolic & Molecular Bases of Inherited Disease, The McGraw-Hill Companies,

New York 2001:3897-933

6. Vitamin B12 metabolism and massive-dose methyl vitamin B12 therapy in Japanese patients with multiple sclerosis. Kira J, Tobimatsu S, Goto I.Intern Med 1994;33(2):82-86

7. Neuroblastoma: an evaluation of its natural history and the effects of therapy, with particular reference to treatment by massive doses of vitamin B12. Bodian M. Arch Dis Child 1963;38(202):606–19

8. Intravenous methylcobalamin treatment for uremic and diabetic neuropathy in chronic hemodialysis patients. Kuwabara S, Nakazawa R, Azuma N, Suzuki M, Miyajima K, Fukutake T, Hattori T. Intern Med 1999;38(6):472-75

9. Clinical trials of ultra-high-dose methylcobalamin in ALS. Izumi Y, Kaji R. Brain Nerve 2007;59(10):1141-47

10. European Medicines Agency (EMEA). Europees openbaar beoordelingsrapport (EPAR) Cyanokit,Londen 2007

11. Hydroxocobalamin as a cyanide antidote: safety, efficacy and pharmacokinetics in heavily smoking normal volunteers. Forsyth JC, Mueller PD, Becker ChE, Osterloh J, Benowitz NL, Rumack BH, Hall AH. Clin Toxicol 1993;31:277-94

12. Regionaal Tuchtcollege voor de Gezondheidszorg te Eindhoven. (Regional Disciplinary Medical Board Eindhoven verdict) Uitspraak van 15 april 2009 nr. 113b Juni 2011

I've been on cyanocobalamin for 45 years and I'm still "clivealive" at 75


It was written by me and posted by Clive..


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Hi i want to ask here. I see that most of you are using Metcobalamin and your experience with it is good. I want to know if anyone has used Metcobalamin and Adenocobalamin combination. I saw one advert from VeganSafe. How good is that? Here is the link



I had the same problem. I found out I have an enzyme that malfunctions at least 30% of the time to break down folate. Plus other vitamin B problems with methylation. So my blood levels of vitamin b12 are in normal limits but doesn't show what form the b12 is in. There are different forms. Active and inactive. I had to get genetic test done. So the more b12 I had i would get the same symptoms of not enough. Same with my iron levels. Found out I also had a gene for hemachromatosis which means too much iron gets stored all over my body instead of excrete it through urine. It was a mutation from my ancestors because there was famine especially during the winter. Yeah. So if there's ever famine again well then I may live longer then most :p As for the vitamin b12, I found an article that was interesting. How the inactive form is made with cyanide. So if you have a genetic defect this could cause a lot of problems similar to the deficiency if vitamin b12. Since the b vitamins help to rid the body of toxins. Plus someone mentions magnesium and potassium levels. My cousin has the same problem and had to see a naturopath who gave her the active b12 shots and now feels fantastic. I can't afford the naturopath so been researching. Glutathione helped and you can get activated b vitamins at the heath food store. I just recently found out that compound pharmacies carry the active b12 shots. The ones docs and other pharmacies carry are the inactive form. I believe it's even synthetic so not really natural which is very annoying.


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