Can you overdose on B12?: I wonder if... - Pernicious Anaemi...

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Can you overdose on B12?


I wonder if you can help - my daughter is 17 and posted for the first time recently. I’m writing on her behalf as I’m her mum.

She went to have her monthly b12 jab this afternoon (I wasn’t with her) and the nurse refused to do it as said her level was too high (now 1242). He checked with a gp and was told yes, you can overdose so not to do it.

Her intrinsic factor came back as normal ☹️ I guess we need a retest.

They made her an emergency appt with Dr next week but this last week her symptoms have been really bad - her face numbness and difficulty swallowing food has been awful, so been holding out for today’s jab.

The nurse started saying needs to investigate her walking into window more as he thinks symptoms are due to that accident back in August- completely not understanding her b12 has been super low.

She is now scared she will overdose on b12 because of what’s been said.

I guess this is the frustration lots of people feel.

I don’t know what to do now - am furious and really upset!

Any guidance gratefully received about how to play this now? Are they wrong?

Thank you


58 Replies

Once on Injections testing is not needed.

No you cant overdose as you wee out what's not used.

Often Gps di use the numbers to stop injections.

If you join PAS they can help you.

If you look at other posts they have links of bnf guidelines ect that will help you.

It should go on treating symptoms.

My surgery also got scared at the beginning ad j got worse before better. I'd had a fall as often people fo when's on b12!

I had to fight for treatment as frequently as I needed it.

Tou could write to the surgery. ? Many on here can give tih facts.

I simply said as j handed my list of symptoms. How are you going to treat me?.

As a mother it's very upsetting seeing toud daughter not receiving her treatment.

Perhaps armed with Info. Toh could gi with her.

There was nothing the nurse could do once or on 'the screen' I was refused one because of a Gps admin error recently. I do hope yoh get if sorted soon.

in reply to Nackapan

Thank you so much -,it feels like a battle at every turn as I thought this line of treatment had been agreed. So frustrating and horrible - really appreciate your response x

The information below, that you cannot overdose on B12, in posted on the right side of this page.

When my GP 'tutted' about my high B12 (2000) I printed it out for her. I also told her that 'testing after injecting was not necessary' according to the NHS guidelines. Someone will give you the reference.

Sleepybunny 's comprehensive list of reference in some posting will, I think, give you answers to many questions about PA and B12 deficiency.

PAS-adminInformation about B12 deficiency from Stichting B12 Tekort and the B12 Research Institute.

in reply to beginner1

Thank you that’s good to know. I’m so angry as they’ve now put fear into my daughter that she can OD! I do worry about the future and her doing off to uni and getting fobbed off. Feels there is so much ignorance ☹️

Really appreciate your message

in reply to SAM2608

Student health at uni. is often very good. One of my daughters had good care. In a way its good to havd the diagnosis before going so you can help get her treatment sorted and she can improve whilst at home. Rather than being miles away trying to help !

With all the links you now have I'm sure she will get reassurance and her injections.

in reply to Nackapan

Thank you - it all feels quite bewildering right now!

in reply to SAM2608

The wrong/no treatment of older people, I'm ancient, is bad enough, but so much worse when it is a youngster, your child. I get very angry.

When the NHS GP's let me down I was lucky to find a private GP. I still see him but self inject every day as do many people on this site (so much for overdosing.)

I suggest you get your daughter to read the 'PAS-adminInformation about B12 deficiency from Stichting B12 Tekort and the B12 Research Institute' to put her mind at rest about overdosing, (the enormous amount they inject into firemen.)

Perhaps she could, herself, post anything she is worried about or wants to know on here so she has some control of what she does.

in reply to beginner1

I think she felt bamboozled to be honest by the nurse and then the nurse calling a GP to ‘confirm’ one could OD on b12. She is still slightly in denial that b12 deficiency is responsible for her symptoms- so it’s tricky to get her to take ownership. She has posted once before and appreciated the input though x

One guy had to have level up to 200 000 to feel any effect of B12. So one can go quite high without any problems. He had to do it quite a while until problem was solved.

in reply to Justiina


in reply to SAM2608

I know! He injected 30mg of B12 every day. That's 30 times normal injection. He is still very much alive and walking but he probably is one of those extreme cases needing that much. Anyways, the point is that your daughter has no reason to worry about overdose.


I'm assuming you're in UK, some info below may not apply if you're in another country.

I wrote a very detailed reply on another thread on the forum with links to B12 books, B12 websites, UK B12 documents/articles and other B12 info. See next link.

I think you will find useful info particularly in the following document. You could print it out and give GP a copy with relevant bits circled.

BSH Cobalamin and Folate Guidelines

I can't remember which page it's on but there is a quote in the document that indicates that testing b12 levels once treatment has started is not necessary.

My personal opinion though is that it is more effective to write a letter to GP when querying aspects of treatment/diagnosis.

I think this is because in UK, letters to GP are supposed to be filed with medical notes therefore letters are less likely to be ignored than things said to GP in appointment or info on photocopies handed over.

When writing a letter relevant quotes from UK documents/articles could be put directly into the body of the letter. This hopefully makes sure the information is filed.

There is a useful summary of mainly UK documents in fifth pinned post on this forum which mentions issue of retesting B12 levels after treatment has started.

"Her intrinsic factor came back as normal "

The above test is not always reliable. It's possible to still have PA even if Intrinsic factor Antibody test is negative (called Antibody Negative PA).

Flowchart from BSH Cobalamin and Folate Guidelines

Flowchart outlines process for diagnosing PA and Antibody Negative PA in UK

If there's any possibility of PA or Antibody Negative PA, I recommend joining and talking to PAS (Pernicious Anaemia Society) soon.

PAS can pass on useful info and offer support and in some cases can intervene on behalf of PAS members.

PAS (Pernicious Anaemia Society)

Based in Wales, UK.


PAS tel no +44 (0)1656 769717 answerphone

PAS support groups in UK, currently 15 in UK, may be one close to you.


Blog post about how PAS can support PAS members seeking PA diagnosis

PA tests

Intrinsic Factor Antibody (IFA) test

Parietal Cell Antibody (PCA) test

PCA is not recommended as a diagnostic test for PA in UK.

Both these tests can be unreliable.

It is still possible to have PA with a negative result in IFA or PCA test.

About 50% of people with PA test negative on IFA test.

About 10% of people with PA test negative on PCA test.

Has she been tested for Coeliac disease which can lead to B12 deficiency due to gut damage?

Even if she has been tested for Coeliac in past I suggest reading following links about Coeliac as it's possible to have Coeliac disease even with negative test results because

1) patient has IgA deficiency (IgA is an immunoglobulin)

2) patient was not eating enough gluten in weeks before blood was taken

NICE guidelines Coeliac Disease

Coeliac Blood Tests

There are other possible causes of B12 deficiency including diet, H Pylori infection, Crohn's disease, exposure to nitrous oxide, parasite infection eg fish tapeworm.

I hope GP has considered these.

There is lots of useful B12 info in next website, I suggest having a thorough read.

B12 Deficiency Info website

Unhappy with Treatment (UK info)?

Letters to GPs about B12 deficiency

CAB NHS Complaints

If you are acting on behalf of your daughter at her appointments, it's possible you may need her signed written permission to do so to keep GP happy.

I normally write much longer posts but too tired at moment. Please read the other forum thread I linked to at top of this page which has loads more B12 info.

I am not medically trained.

in reply to Sleepybunny

Got it - thanks for so much valuable info, have just printed off lots to take to GP x

in reply to SAM2608

I'd also suggest writing a letter to GP either before or after as a follow up with relevant info in it.

I suspect much of the detailed info I photocopied for one set of GPs was filed in the bin whereas a letter to GP should be filed with medical notes.

I suggest trying to speak to PAS before her next appointment. You would need to be a PAS member.

Might be worth referring GP to section on PAS website for health professionals


Have a look in PAS library section if you join as you could print out some of the leaflets for GP.


I think " An Update for Medical Professionals: Diagnosis and Treatment " is particularly useful.

If you struggle to get recommended level of treatment then may be worth talking to your MP.

Next articles from Dutch B12 website so units of measurement/reference ranges may vary from those in UK.

Misconceptions about a B12 deficiency

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

Local Guidelines

Some parts of UK are using out of date local area guidelines on treatment/diagnosis of b12 deficiency. I suggest you track down local guidelines for your part of UK (if you're in UK) and compare them with BSH guidelines (link in my other post) and links below.

You may have real battle on your hands if you're in one of these areas.

BMJ B12 article

Emphasises need to treat patients who are symptomatic even if their B12 level is within range.


BNF guidance on treating b12 deficiency changed recently.


BNF Children


These books may be of interest. Some of the case studies in them may be upsetting to read.

B12 books I found useful

"What You Need to Know About Pernicious Anaemia and B12 Deficiency" by Martyn Hooper

Martyn Hooper is the chair of PAS (Pernicious Anaemia Society). Be aware that book does not show updated BNF info.

"Living with Pernicious Anaemia and Vitamin B12 Deficiency" by Martyn Hooper

Has several case studies.

"Could it Be B12?: An Epidemic of Misdiagnoses" by Sally Pacholok and JJ. Stuart (USA authors)

Very comprehensive with lots of case studies. There is also a paediatric version of this book "Could It Be B12? Paediatric Edition: What Every Parent Needs to Know".

"Vitamin B12 deficiency in Clinical Practice" (subtitle "Doctor, you gave me my life back!" by Dr Joseph Alexander "Chandy" Kayyalackakom and Hugo Minney PhD

Good luck

How utterly frustrating. Sighing as I type.

Sleepybunny has posted it already but love this paper on frequent misconceptions. Clear, concise and not at all threatening to egos! Well one can hope. And covers how one can not overdose on b12.

The information about not retesting and following symtoms not serum value ---- #4 and #5.

And feel free to highlight the heck out of #6 for them - about how one can not overdose on b12. Lord give us patience.

And I remember your daughter posting. Walking into the window could have been a vitamin b12 deficiency symptom - a disorder of proprioception (knowing your body's position spatially). I was consistently called clumsy and used to cut people off walking all the time. And I would swear I was walking in a straight line and they had the problem.

EDIT: I just realized I left the same link with your daughter. Hope she gets better care soon.

Like others have said you cannot overdose on b12 as any excess is excreted via your urine. The nurse is talking total nonsense & clearly doesnt know what she is doing. Infact what she has done will cause harm. I would contact the PA Society's helpline they can talk to her GP to get this resolved. Her symptoms sound neurological and therefore she should be having jabs every other day until there is no further improvement. So actually the monthly jab is likely not frequent enough unless it resolve all the neurological symptoms!!

There is no need for retesting of B12.

Like others I have to inject daily otherwise I deterioate, numbness, tremors, motor decline etc return/increase. Stopping the monthly jab is outrageous!

in reply to waveylines

Thank you for your reassurance that I’m not going mad/over reacting! I’ve written a letter to gp and printed off info from pas website- got a call booked with the gp at lunchtime, so hopefully get this sorted by end of the day.

Can I check, if neuro symptoms still present after loading dose 3 months ago, is it still recommended she has every other day injections?

Thank you again

in reply to SAM2608


"She went to have her monthly b12 jab this afternoon"

Many UK members on forum can only get a jab every 3 months.

For adults

1) UK recommended treatment pattern for B12 deficiency without neuro symptoms is ...

6 B12 loading jabs over 2 weeks followed by a jab every 2 or 3 months

2) UK recommended treatment pattern for B12 deficiency WITH neuro symptoms is ...

A B12 loading jab every other day for as long as symptoms continue to get better then a jab every 2 months

Both patterns allow for maintenance jabs every 2 months.

For those without neuro symptoms, it used to say maintenance jabs every 3 months but this was changed about a year ago to say every 2 - 3 months. Her GP may not know that BNF guidance has changed.

If she is being treated as a child then treatment patterns for those without neuro symptoms are a bit different to that for adults

Details of UK B12 treatment in BSH, BNF, NICE CKS links in one of my other posts on this thread.

GP can also find this info in Chapter 9 Section 1.2 of their BNF (British National Formulary) book

"if neuro symptoms still present after loading dose 3 months ago, is it still recommended she has every other day injections?"

What pattern of loading doses did she have when she started treatment?

If no neuro symptoms present at that time, I would have expected her to have had 6 loading jabs over 2 weeks. I'm assuming that as she is 17 (?) she would be treated as an adult.

Child loading doses

If she is being treated as a child rather than an adult the pattern of loading jabs for those without neuro symptoms would usually be a quarter of 1mg up to 1mg every other day for 1 to 2 weeks then a quarter of 1mg once a week until blood count is normal followed by a jab (1mg) every 2 or 3 months.

If she had neuro symptoms before start of treatment, I would have expected her to have had a loading jab every other day for as long as symptoms continued to improve then a jab every 2 months. This pattern is used for both children and adults with neuro symptoms.

There is no time limit on how long the every other day loading jabs can continue. If symptoms are continuing to improve the every other day jabs could continue for weeks even months.

BSH guidelines suggest possibility of a review after 3 weeks of every other day loading jabs but after 3 weeks my understanding is that every other day jabs should still continue if improvement is still happening.

If you feel she did not have the right pattern of loading jabs at the start of treatment you/she may be able to negotiate with GP to have another set of loading jabs.

If her neurological symptoms have developed since her treatment started may be worth discussing with GP whether she needs to start loaidng doses again.

There may come a point in treatment where GP feels patient has improved as much as they are going to on loading doses and will then move them onto maintenance jabs every 2 or 3 months.

My personal experience was that it took many weeks even months of loading jabs to get any improvement in my neuro symptoms. I was self treating as I had been refused NHS treatment.

Many on forum report that symptoms get worse before getting better. PAS may be able to tell you more about this.

Even if her GP does not accept she has neuro symptoms she should be able to at least get maintenance jabs every 2 months.

Symptoms list

Have you together written a comprehensive list for GP of every symptom she has especially every neurological symptom?

Does she have any of the following neuro symptoms?



pins and needles

burning sensations

insect crawling sensation (known as formication)

tinnitus (there are several types of tinnitus)

muscle twitches

muscle fasciculations (ripple like movements of muscles)

flickering eyelids

restless legs syndrome RLS

periodic limb movements




dropping things

bumping into things

strange gait (unusual way of walking)

word finding problems (known as nominal aphasia)

memory problems

balance issues



proprioception problems (problems with awareness of body in space)

strange behaviour eg putting keys in fridge, boiling kettle without any water etc

dystonia type symptoms

The above are only some of the neuro symptoms that can be associated with B12 deficiency.

Check the next links which have more neuro symptoms listed

Symptoms of B12 Deficiency


In relation to B12 deficiency, GPs often look for signs of peripheral neuropathy PN especially signs of sensory neuropathy so worth mentioning any signs of PN.

Link about PN

Link about writing letter to GP if under treated for B12 deficiency with neuro symptoms

You could draw the GPs attention to the possible consequences of under treatment if you feel she is not being treated adequately.

Neurological Consequences of B12 Deficiency

PAS news item


PAS article about SACD, sub acute combined degeneration of the spinal cord, access to PAS members only.

pernicious-anaemia-society.... See Page 2 of articles.

Blog post from Martyn Hooper's blog, mentions SACD


If neuro symptoms present, has she been referred to

1) a neurologist?

If she see a neurologist, ask them to check her proprioception sense.

Two tests that help to do this are

1)Romberg test

2)walking heel to toe with eyes closed.

Problems with proprioception can be associated with B12 deficiency.

Vital that these tests are only done by a doctor due to risk of loss of balance. If no tests are done with patient's eyes closed then unlikely that proprioception has been fully tested.

2) a haematologist?

NICE CKS link recommends that GPs seek advice from a haematologist for patients with b12 deficiency with neuro symptoms.

If GP won't refer her, they could at least contact a local haematologist by letter and ask for advice.

Don't expect better treatment from a specialist, ignorance about B12 deficiency exists among specialists as well as GPs.

I hope you have a good experience if she is referred.

I used to request referrals in a letter to GP along with supporting evidence eg symptoms, tets results, family/personal medical history, extracts from UK documents/articles.

Always keep a copy of any letter written and have a copy in bag at appointments in case GP loses their copy.

I feel it's useful to have a paper trail in case there is a need for future complaint.

If gut symptoms present, has she been referred to a gastro enterologist?

Gastro specialist should be able to spot signs of gut damage from PA, Coeliac, H Pylori etc and may be able to work out what has caused her B12 deficiency.

Tracking down local guidelines

Have you managed to track down the local guidelines for the area of the UK you live in?

Ways to find local guidelines include

1) Internet search using " name of area B12 deficiency guidelines"

2) Search local NHS website, try under haematology policies.

3) Ask practice manager at GP surgery for a copy of the guidelines surgery is using...this may irritate them.

4) Submit a Freedom of Information (FOI) request to local NHS website/practice manager of GP surgery

5) Local MP may be able to help track them down


I feel that parents are not always fully respected when trying to get right level of treatment for their children. See blog post below.

Good luck.

Yes she should continue with alternate day injections for as long as it takes - this can be years! Good luck with the GP. Let us know how it goes.

Meant to say the letter is a good idea. If you get nowhere with the conversation, a polite formal letter and requesting its put on her medical record often triggers action. Sad to say but its the fear of liability that worries them. No one wants to be at odds with their GP but am afraid keeping quiet will not get her well. Am always polite but insistent.....

Hope it goes well. Knowledge is power!

in reply to waveylines

Promise this is my last question (for now)! But where do I find that piece of info about alternate day injections- is it in guidelines? I’m getting in a pickle trying to take in so much new information :)

in reply to SAM2608

These documents should each have info about UK B12 treatment

BSH Cobalamin and Folate Guidelines


BNF Children


Thank you 😊


The treatment for cyanide poisoning is 5g hydroxocobalamin (that's 5000 times the amount of B12 your daughter is receiving) injected intravenously over 15 minutes with a repeat dose after 30 minutes if needed. This is the preferred treatment because of lack of toxicity. The risk factor is the amount of fluid that is needed to deliver 5g of hydrocobalamin which can cause hypertension.

So, no you can't overdose on B12!

CherylclaireForum Support

Tell her not to worry. There is no research that shows any ill effects from high levels of B12. Massive levels of B12 are used as an anti-toxin for serious cases of poisoning.

It seems a shame, but for some reason, once loading dose is over and body is expected to function on 1 injection every 3 months, for some people, symptoms seem to get much worse. A lot of people find that they need more than this to recover. There is research currently which will be able one day to distinguish who needs more and why- and then we won't all end up deteriorating !

I have been at over 2000 ng/L (measurable limit) when having injections every 3 months and stillI been very symptomatic. My GP found that my MMA was raised which is when she restarted my loading dose: I had 2 injections a week for 6 months. After she checked that my B12 was still high (yes, over 2000 ng/L) she was satisfied and never tested for it again- but regularly checks my folate, ferritin, thyroid levels as these can drop despite supplements. Same with vitamin D which I get on prescription because of osteoporosis of the spine.

She also started to send me to experts : neurologist, haematologists, gastroenterologists, oral medicine and metabolics consultants. She did the right thing and acted quickly. No real answers yet.

Yet all my symptoms are well documented as being related to B12 deficiency - on lists that many GPs don't seem to be familiar with.. I've now accepted (I think) that some of mine might not go. Most have and I'm more able to manage my condition, whatever it might be.

I have now self-injected for over 2 years every other day, and have recently reduced that to twice a week -because I'm getting better. Everyone acknowledges this : friends, family, partner and GP.

Not perfect, but certainly alive !

If only GPs would panic so much when we feel like we're dying- not just when they believe we should be !

Thank you for your reply. GP has agreed to give injection tonight and suggested getting a team around her so everyone is aware at the practice. Also seems not averse (I think?!) to moving to every other day injections until symptoms improve- and possibly haematologist appointment. We have a review with our usual GP next week - so here’s hoping.

It’s a very misunderstood and complicated condition isn’t it?!

So helpful to hear others experiences so thank you

CherylclaireForum Support
in reply to SAM2608

Yes it is, SAM2608 - and can be quite lonely.

You are doing exactly the right thing for your daughter.

Practice working as a team is a really good move: I had my NHS injections stopped by a GP I had never seen before, when my own GP was on holiday.

I think every other day injections until symptoms stop improving is how treatment for those with neurological symptoms is described. This can take a long while.

If your daughter has had neurological symptoms, she should be referred to a neurologist. This might take a while too (over 6 months) so in the meantime, rest assured that frequent injections could prevent further damage, could make a lot of difference by reducing or removing symptoms, and certainly would do no harm.

Please let us know how you both get on. Wishing you well.

Thank you so much - he had consulted with our GP when we arrived this afternoon and every other day injections start now until symptoms stop improving- I ‘hope’ he isn’t expecting this to be instantaneous, but feel they are on side now at least and he was very apologetic for what happened.

Thanks again for your input x

in reply to SAM2608

Might be a good idea to keep a daily symptoms diary which tracks how symptoms change over time and when jabs are given.

This could be useful evidence for GP/specialist of improvement (can also be evidence of deterioration).

Don't be surprised if they try to stop the every other day jabs after 2 or 3 weeks; which is why you need to build up evidence that she is improving and documents that show every other day jabs should continue if she's still improving.

Hopefully she'll get the right level of treatment and start to feel improvement soon.

Is the neurologist (and haematologist) aware of the possibility of Antibody Negative PA?

Might be worth having a copy of this flowchart in your bag.

Flowchart from BSH Cobalamin and Folate Guidelines

Flowchart outlines process for diagnosing PA and Antibody Negative PA in UK

Are they going to test her again for PA in the future?

Results of IFA test can be affected if blood taken close to a B12 jab so they'll probably wait until she's on maintenance jabs every 2 months.

Martyn Hooper, chair of PAS, tested negative on IFA test on more than one occasion before finally testing positive.

Are they going to test for Coeliac?

Make sure they do both first line tests, tTG IgA and Total IgA.

She will need other tests for Coeliac if she turns out to be IgA deficient.

She also needs to be eating plenty of gluten in more than one meal every day for several weeks before blood is taken. See Coeliac UK website for more info.

Have they tested for H pylori infection yet?

H Pylori infection

I have read articles online that suggest a possible association between H Pylori infection and PA.

Has she had any exposure to nitrous oxide?

Nitrous oxide inactivates B12 in the body.

Nitrous Oxide


If she's ever eaten raw or undercooked fish eg sushi, smoked salmon etc they may want to consider the possibility of fish tapeworm infection. One potential sign of fish tapeworm infection is an increase in eosinophils, a type of white blood cell WBC. Result for eosinophils can be found on Full Blood Count results.

There are other parasites that can be associated with b12 deficiency, other types of tapeworms and Giardia Lamblia. Giardia is the most common gut parasite in UK. there are other parasites as well as the ones I've mentioned that may have an effect on b12 levels.

If she's ever lived in or visited an area where internal parasites are common, may be worth mentioning that to GP/specialists.

Link about "What to do next" if B12 deficiency suspected

Blood tests


Full Blood Count and Blood Film

Folate Deficiency

Have they checked her folate levels recently?

Iron Studies

Have they checked her iron levels recently

Access to Blood test results (England)

Prescribing off Licence

GPs and specialists can prescribe off licence if it is their professional judgement that it is right to do so for the patient.

Some GPs are reluctant to do so for fear of being sanctioned. Some GPs may have restrictive local guidelines that control what they can prescribe.

Low Potassium (Hypokalaemia)

Some people experience a drop in potassium levels when B12 treatment starts. If she has any symptoms that make you concerned may be worth asking doctors to check her potassium levels.

See side effects section in next link


Some forum members try to eat foods that are rich in potassium eg bananas.

Personally I do not think it is a good idea to take potassium supplements unless they have been prescribed by a doctor. Excess potassium can cause issues in the body.

CherylclaireForum Support
in reply to SAM2608

Sleepybunny has suggested a daily symptoms diary, tracking what happens - any improvements- and how these relate to the injections (and any frequency changes).

This is a very good idea, because you are right: at the 3-week review, how will GP determine whether to continue or not ? Based on improvements ? Based on lack of improvement? Based on observation ? Blood tests ? In a 10-minute consultation, what will they see ? Or miss?

I still do this: I'm now on chart 22 !

I listed all symptoms down left-hand column of landscape A4 table, and all dates along the bottom, and just used diary info to colour in when symptoms are present- and add where injections done. Some consultants think this obsessive (maybe "desperate" a nearer description !) but some are very interested and find it useful.

I also took photos of any visible symptoms at their worst: this was very useful, because not all symptoms are present in the few minutes of the consultation. Oral Medicine consultant looked at a few photos dating back years- and was able to tell me where I was very ill, that I am improving, remaining concerns etc. Seeing him again next month.

Some symptoms have gone, some now much less severe, but some have been very slow to improve- and this can be disheartening. Looking back at diaries from earlier days gives me a lift, keeps me determined.

Sleepybunny also said that the IFab test (anti-intrinsic factor antibody) is unreliable - and that Martyn Hooper, founder of the Pernicious Anaemia Society, had several negative tests before an indisputable positive. This is true- he writes in his book that he had 3 tests in all. This would be difficult to get, I should imagine, as most GPs are unaware of the lack of accuracy of this test. False negatives are so likely that only 40 -60% of cases will be positive. It can only test for an auto-immune reaction to intrinsic factor production, and not for lack of intrinsic factor being produced in the first place.

This can make things very complicated and frustrating- for patients, their families, and for GPs and consultants as well. They seem to be working with you now and have apologised for poor decision earlier. I've never met a GP or consultant who knows as much as the PAS team and administration on this forum. This is why PAS helpline is used by so many professionals. Rather than searching for an expert, look instead for caring and kindness in a GP/ consultant, and a willingness to find answers, however long it takes. A tenacious spirit that you and your daughter can rely on and trust.

Otherwise you will wear yourself out. Very well done for getting things moving fast- best wishes to both of you.

Thank you so much.

I’ve made a table that sounds similar- it’s getting a 17 year old to remember to complete it I struggled with - have to do a lot of nagging 😊

However we will keep at it and hopefully make some positive progress with her symptoms.

Luckily the GP yesterday had been doing some research about the IF test and it’s unreliability- so agreed to treating symptoms despite the result. I am so thankful for this forum - it’s been invaluable this past couple of weeks x

in reply to SAM2608

Glad to hear they have got a team together to help her.

If there's a local PAS support group close to you they may be able to offer moral support.

If you're not happy with how things work out, I suggest speaking directly to PAS. They may be able to get involved in some way.

"possibly haematologist appointment"

Make sure you're as well prepared for this appointment. Sadly some haematologists are lacking in knowledge about B12 deficiency as are other specialists.

I agree with Cherylclaire that she should be referred to a neurologist.

She should also see a gastro specialist if gut symptoms present.

You'll probably have to continue to be proactive and request these referrals. GP surgeries have many financial constraints which sadly may affect their willingness to refer.

Help for GP

You may be able to arrange for her GP to speak to PAS but would need to discuss this with PAS first. best to phone them.

PAS (Pernicious Anaemia Society)

Based in Wales, UK.


PAS tel no 01656 769717 answerphone

in reply to Sleepybunny

Thank you for all the amazing information x

Wonderful news.

Thank you - I hope so x

Brilliant! Well done that sounds very positive. Heres to alternate day injections. It does take a long time but some things go quicker than others. Ive been at it now for 18months. Am much much better than I was.

And yes you will have to carry on being proactive. Doctors surgeries seem overwhelmed these days so Ive found I have to chase up every medication no matter how long they have been on repeat. All signs of an underfunded

in reply to waveylines

I know, I’m so grateful for the nhs and they are so so overstretched. Really hoping that we start to see some improvement and they give it enough time to make a difference.

Thank you for your kind words

Hi, here is an interesting article on B12 overdoses, hope it helps. I always wondered if you can overdose and though there is no set B12 amount stated as too much, it seems it depends on other health factors and medicines you might be taking. From extensivve reading it seems to be very rare, but I am no expert.

CherylclaireForum Support
in reply to B12Healthy

Basically, acne then !

Compare that to B12 deficiency symptoms affecting hair, eyes, brain, muscles, cognition, hearing, skin, nails, balance, ability to walk, ability to work, ability to understand what people are saying to you, etc, etc, and a few spots are hardly worth noting.

In fact, I welcomed my B12 spots as a sign that something was finally working !

Even now, if I have a "low blip", on recovering, the spots will reappear. This is rare now for me. The ones inside my ear canal were the most irritating .

I know for some people, this is a bigger issue, but generally these spots go after a few days and stop returning once other improvements start happening.

The other overdose indicators mentioned sound more like residual B12 deficiency symptoms -which can often get worse before better- and so I would question how the difference was determined.

That’s interesting as my daughter has developed a lot of spots on her forehead having had very clear skin. They seem to be clearing up now though - not sure what that indicates though...

CherylclaireForum Support
in reply to SAM2608

Stick it down in the diary - a pattern might emerge !

These are not exactly like ordinary spots- they might have seemed like that at first to your teen-aged daughter- but I was in my mid-50s.

Hi, I don't want to be flippant but you can overdose on anything even water, but like water overdosing on B12 is difficult to do. Try to stick to the schedule your Dr has for you and discuss if you feel your symptoms coming back, you know your body better than anyone

in reply to jatkowski

There is no known toxic dose for B12. So it's not like water.

I really dont think you need to worry about overdosing. There is no known case! That is what my NHS neurologist said -he is very into B12 and is researching it. Even extremely large dose of b12 have not caused a problem because the body excretes any excess. This is not always the case with vitamins- vitamin A being one and there are cases of overdosing on vitamin A as any excess can not be excreted.

The protocol you should follow is the one that suits your daughter. To some degree it is trial and error. For example alternate days may suit your daughter or she may find now or later on that some symptoms are coming back on the day she isnt injecting and therefore needs to increase. Currently no one knows why some people need to inject more frequently than others. Theres also no accurate medical research defining the frequency of injections. The guidelines are arbitory. They are great for a starting pont but dont get hung up on them.

How wonderful that you have a neurologist that is researching b12.

Yes hes interested in the effects of B12 on tremors........ so its good he wants to research..... lets hope some good comes out of it!

For everyone reading along -

#6 on this article talks directly about b12/misconceptions about high amounts and overdosing.

Brilliant article Litatamon Thankyou!! Have saved it....

I suspect Ive had a B12 issues for about 15yrs when I forst started with tremors & fatigue -latter put down to part of hypothyroidism. Unfortunately I remained well in range in B12 tests so it was dismissed confused no doubt by my b12 supplements which did NOT improve my tremors which mystifies me!

Interestingly its the daily B12 jabs that has improved my tremors beyond all recognition but I accept due to damage am extremely unlikely to be completely free of them. So I dont believe the B12 tests are very good at picking up b12 deficiency accept in the more extreme cases. Shame doctors rely so heavily and rigidly on them. When I queried the initial refusal for B12 treatment the response I got was "we have other patients like you with tremors we dont treat them!" Scary! The mind boggles.....

It is truly scary. My doctor asked me about changes after my loading shots. There were so many that I started listing with glee. She asked.

She heard about three - one of them was eyes (double/blurred). She literally told me that my eye change had nothing to do with b12, which such confidence, and I needed to see an optometrist. Usually I placate a bit to keep a strong relationship but I had to think of her other patients. So I said it is definitely a documented b12 symptom but of course I will still see an optometrist regardless.

She then stopped the listing and said "Can I just hear about your energy level?" said as if energy/exhaustion was the only symptom.

And she is a wonderful doctor in many ways. So I can't imagine one which a large ego!



Just in case you aren't aware -

Could it be b12? Sally Pacholok - both the video and book talk at length about people such as yourself that sit in normal range but have all the symptoms.

All the best to you.

Ahh I have the book & watched the film me on the track of b12. I was scared of self injecting.....but finally made the plunge! Haha! After 9 months of self treatment I got it finally on the nhs....self injecting (saves them money) but then my GP said I have to get the nurse to approve your techniques....another month passed before nurse could see me......but GP knew all those months I was doing it......bonkers beurocracy!! Honestly if Id waited for the nhs I would've been in a wheelchair!


"My doctor asked me about changes after my loading shots. There were so many that I started listing with glee"

I started including a list of all the improvement in symptoms in letters to GP so there was a record on file. I had been forced into self treatment as was refused treatment by NHS.

Will be definitely doing that soon. Thanks Sleepybunny.

Sleepybunny always lists that article. I just highlight it because I am partial to it. And feel that it shouldn't make any doctor feel attacked.

Unreal that we have to be so sensitive to a lack of knowledge, but we do. Frustrating.

Thank heavens for this site and all the wonderful knowledgeable people on it!! 🤗🤗🤗

in reply to Litatamon

So helpful , printing off to share with GP I think - thank you so much

CherylclaireForum Support

It does, as Litatamon says, make life hard when so many of our symptoms, listed commonly on every website run by those who actually have this condition, are not accepted as valid by GPs or consultants.

Most of these lists have been compiled via research questionnaires completed only by those with an indisputable Pernicious Anaemia diagnosis (getting ever rarer !) despite their being common to all who have B12 deficiency.

Nevertheless, GPs are getting there first, before consultants, simply because if you see the same GP over and over and over, eventually they will notice that you have visible symptoms (if you are "lucky") that are only noticeable when you aren't doing so well.

I'm honestly starting to believe that GPs are taught that the only symptom of B12 deficiency is tiredness (not necessarily fatigue) and those first 6 injections will get you right back on track. Unless of course you are also depressed.

I don't see people like me:

who, for instance, have a spate of overlapping loud yawns, who have sore lips that are red, split and bleeding. I do look for them. How many conditions have both of these as symptoms ? Yet it has been 5 years since I went to the GP, and probably the sore split mouth started another 10 years before that.

It's well gone time now.

Well perhaps these additional symptoms could narrow it down, if they were acknowledged by anyone in the medical profession as part of the same condition, and not just familiar to some of you here:

They still include

- hair loss after hair condition deteriorating

- fingernails splitting, cobbling, and vertical splits and bloodlines

- tinnitus that seems to be inside head not ears

- cognitive impairment especially if person talks quickly, interrupts -or a group talking, or TV on, or in restaurant, pub or noisy place (inability to phase out background noise)

- inability to concentrate: read a book or listen to music or spend long on the phone

- inability to understand complex concepts or detailed instructions

- daily diarrhoea

- low folate and ferritin unless supplementing- and even then can drop

- short-term memory problems- forgetting end of sentences, simple nouns, names, bath, cooking etc

- stiff painful feet on waking and backache

- osteoporosis of the spine

- thick burning tongue, white-coated, red at edges and sore throat

- aching joints: especially hips, knees, ankles- but also shoulders ..difficult to find comfortable sleeping position because of this

- ...yet oversleeping (12+ hrs) and/or napping

- difficulty walking- having to think about it, feeling like legs tied together above knees

- muscle weakness (arms. legs)- when grating cheese or changing duvet cover for example

- craving solitude - having a day off from people, just to recoup, even from those I love immensely

- mercurial mood-swings

This list does not include everything, just those that came to mind first.

I have read your posts and am well aware that I have got off lightly in terms of both quantity and severity of my particular set of symptoms. Yet I have lost my position at work, returning into a lesser role and in a part-time capacity- and know myself to be lucky that I was taken back at all after 15 months of being totally unemployable.

I can walk, I can express myself, I can speak for myself now in consultations.

I'm not yet me - but trying.

I have good days. For all those who are still struggling, it may not seem like it yet - but it is possible. It can take a while : keep going, keep asking the questions. Help is here.

Hi Cherylclaire,

I was told it was hypochondria, psychosomatic, depression, ME/CFS, Fibro etc...many of the common misdiagnoses of B12 deficiency...despite having a diagnosis of B12 deficiency in my past.

These are just some of my symptoms when I was at my worst

constant fungal infections eg ringworm/thrush (think my immune system was compromised in some way)

constant bad dandruff(?) on head..lmay have been dry skin rather than fungal

dry skin on arms and legs ( wasn't psoriasis)

sore spots at corners of my mouth

what looked like bite barks along edge of my tongue

damage to papillae (tongue cells) on tongue

tingling and pins and needles; over body but particularly in tongue, groin, hands, also teeth and spinal cord

tingling to the point it felt like burning on some occasions

sensation like water was trickling on my skin

insect crawling sensations; felt like I had ants crawling all over me (formication)

moons (lunula) on my nails disappeared, nail growth slowed

migraine symptoms


mood swings


post natal depression

crying out of the blue for no reason



memory problems

couldn't get the right words out (nominal aphasia)

lost ability to mental arithmetic quickly, had always been good at maths

lost track during conversations

mental blanks

periodic limb movements

restless legs syndrome RLS

dystonic type symptoms

Link below is about dystonia


internal vibrations

painful muscles, joints, bones,

My eyes constantly felt painful

tinnitus, at least three different types

lower back pain

intermittent numb spots over body

eyelid flickering

hair loss and not just on my head...used to touch my eyelids and my eyelashes would fall out

agonising muscle contractions in the muscles between my ribs

random muscle twitches over body

muscle fasculations (ripple like muscle movements under the skin, used to look like something was wriggling underneath)

vertigo (couldn't cope with being high up or near a cliff edge)

extreme fatigue

constantly yawning

no stamina/strength; had to prop myself up on furniture, legs felt like blocks of wood

inability to walk more than short distances without stopping

muscles felt weak, couldn't mix a cake

brain fog


extreme sound sensitivity

intermittent mouth drooping on one side (not a stroke, think my muscles were affected)

IBS for years; diarrhoea, painful constipation

feeling like food was stuck in oesophagus; think food was travelling too slowly down oesophagus

acid reflux type symptoms (actually think I probably had low stomach acid)

Proprioception problems; balance was poor at night, when eyes closed, when I lost sight of surroundings, misjudged distances when reaching for things

heavy periods

lost the ability to do more than one thing at a time eg could no longer read while listening to music

strange behaviour eg keys in the fridge

The above are only some symptoms and there were quite a few others.

I kept saying to GPs that I felt there was one underlying issue that was causing the majority of symptoms but was disregarded...over 15 wasted years.

I found various articles that associated most of my symptoms with B12 deficiency and I found anecdotal stories online that linked some of my more unusual symptoms eg visual snow with B12 deficiency.

CherylclaireForum Support
in reply to Sleepybunny

I feel lucky that my GP realised that something was going wrong rather quickly after the 3-monthly injections started- I am sure that her quick reaction in restarting loading frequency is what stopped me from deteriorating further, and why finally I was able to improve. Like you, I always knew that all of these problems had just one source.

This is why I would not take the anti-depressants offered (more than once).

Still wish that these symptoms -of which many must be highly specific- were more easily identified as belonging to B12 deficiency. If only GPs knew more about what this felt like and could lead to, they would be straight on it as a matter of urgency.

Such a waste: lost years and loss of faith in the medical profession, alongside all the other losses (hair included!) If the teaching doesn't improve, how can the GPs - and so how can we ?

Thanks for your honesty, Sleepybunny - and the years of support.

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