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Pernicious Anaemia Society
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New here... can I ask for some guidance, please?

Hi, I have recently begun taking b12 orally and not sure if I am taking enough.

My b12 level is 190 (180-900), and my GP is not willing to treat me, but doesn't seem bothered whether I take supplements or not. I have been experiencing tiredness, lethargy, heavy and aching limbs, frequent headaches, mental fogginess, memory problems, tingling and numbness in my hands, and palpitations. My hands and feet also burn. This has been getting increasingly worse over the past 18 months.

My iron stores are also low - my ferritin is 9 (15-40).

I am 50, and I think these symptoms have been mixed up with perimenopausal issues for some time, which is confusing the issue (intermittent menstruation, mood swings, anxiety, low-libido). My diet is pretty good, although I don't eat red meat. I do eat cheese, fish, dairy, lots of leafy veg, fruit and pulses, and a small amount of chicken/turkey.

My GP has prescribed 400mg ferrous sulphate a day (for 3 months) but said my b12 isn't low enough to treat. He said the iron deficiency could be causing all the symptoms.

My father has Pernicious Anaemia and has 3-monthly b12 injections.

I have decided to take b12 orally, and have bought some 1000mcg b12 methylcobalamin. Is one of these a day enough, or should I be starting on a higher dose? Also, how long approx will it take to be effective? I am starting to get a bit desperate...

Thanks for any help you can give!

16 Replies

I think that your B12 level is too low and therefore should be treated.

I am unsure about the frequency of the dose of sub lingual B12 though. Others on here are more experienced on how to advise re doses etc.



PA does seem to run in families. Have you had an IF antibody test. More expert help will be along tomorrow.


Thanks, beginner1. No, I haven't. I wasn't offered it, and I didn't know to ask...

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Are you in UK?

It can be helpful to know which country a person is in, as patterns of b12 treatment vary between countries.

If you're in UK, I'd suggest reading "BSH Cobalamin and Folate Guidelines". It's a UK B12 document that was published in 2014 and gives guidance to UK doctors on treatment and diagnosis of B12 deficiency. My experience has been that not all UK GPs are aware of this document. I gave my GPs a copy.


Flowchart from BSH Cobalamin and Folate Guidelines


Above flowchart makes it clear in UK, that people who are symptomatic for B12 deficiency should have an IFA (Intrinsic Factor Antibody) test and start initial B12 treatment. This applies whether B12 is low or within range.

B12 Deficiency Symptoms

pernicious-anaemia-society.... see PAS checklist

I gave my GPs a copy of PAS checklist with all my symptoms ticked.



IFA test can help to diagnose PA but test is not always reliable and it is still possible to have PA with a negative result in IFA test (called Antibody Negative Pernicious Anaemia).

"Hi, I have recently begun taking b12 orally "

One issue with taking B12 supplements without a confirmed diagnosis is that it can make it extremely difficult to get a diagnosis.

What to do next?




I resorted eventually to self treatment only after I had exhausted all avenues in the NHS to get it.

"My father has Pernicious Anaemia"

With PA in the family, has GP considered the possibility of PA? Have you had an IFA test?

Who gets PA and B12 deficiency?




PAS Pernicious Anaemia Society

Have you considered contacting PAS? I'd suggest soon.


PAS tel no +44 (0)1656 769 717 answerphone so messages can be left. May take a few days to get a response.

PAS is helpful, sympathetic and a good source of information. Some forum members join PAS. PAS are based in UK but have members from around the world.

Martyn Hooper, chair of PAS, has an interesting blog about PA and B12 issues on PAS website.


Other B12 info

Some may not apply if you're not in UK

1) Pinned posts on this forum. I found it very helpful to read fbirder 's summary of B12 documents. Link to summary in third pinned post.

2) BMJ B12 article


3) BNF (British National Formulary) Chapter 9 Section 1.2


UK B12 treatment info is also in BSH Cobalamin and Folate Guidelines, about a quarter through document.

4) B12 Deficiency Info website

Lots of b12 info an an interesting blog about b12 issues.


The person who runs the B12 Deficiency Info website can be contacted by e-mail. Details on website.

5) B12d.org website


6) Book "What You Need to Know About Pernicious Anaemia and Vitamin B12 Deficiency" by Martyn Hooper. Book is up to date with UK B12 guidelines. I gave a copy of this book to my GPs.

He has written two other books about PA and B12 deficiency.

I also found "Living with Pernicious Anaemia and Vitamin B12 Deficiency" useful as it has several case histories in it and I could recognise aspects of my experiences in the case histories.

7) Book "Could it Be B12" by Sally Pacholok and JJ. Stuart (USA authors)

Very comprehensive book about B12 deficiency with lots of case histories. Reading this book was a light-bulb moment for me.

Consequences of lack of treatment

I have read that there is a window of opportunity in treating B12 deficiency and that some symptoms may become permanent if B12 deficiency is not treated or is inadequately treated.

I think some forum members have mentioned SACDSC (sub acute combined degeneration of the spinal cord) to their GPs as a potential consequence of lack of B12 treatment.


There is an article in PAS library section on website about SACDSC, it is available to PAS members. An internet search will bring up other articles about SACDSC if people are not PAS members.

SACDSC is also mentioned in this blog entry on Martyn Hooper's blog.


Neurological Symptoms

You mention symptoms such as tingling, numbness, burning sensations, memory problems which are usually considered to be neurological.

In UK, people who have B12 deficiency where there are neurological symptoms, are supposed to get more intensive B12 treatment. See BNF link and "BSH Cobalamin and Folate Guidelines" link above.

My experience has been that B12 deficiency is not as well understood by some doctors as it could be so my advice is to read up about B12 deficiency. Do you have someone supportive who will go with you to appts?

Full Blood Count (FBC)

Have you had a FBC recently?



Low iron can lead to small red blood cells (microcytosis). Low B12/low folate can lead to enlarged red blood cells (macrocytosis). A person with both low iron and low B12/low folate may appear to have a normal range MCV(mean corpuscular volume) on FBC becuase the effects of low iron on red blood cells may mask effects of low B12/low folate.

Have you had a blood smear/blood film?


Access to medical records (UK)

The most important thing I learned to do was to always get copies of my blood test results. I learnt to do this after being told everything was "normal" and then finding abnormal /borderline results on the copies.




Other conditions

There are conditions which have symptoms that overlap with those of b12 deficiency.

Has GP excluded Thyroid problems?


Coeliac disease?


Unhappy with treatment (UK)?

Letters to GP about B12 deficiency




HDA patient care trust

UK charity that offers free second opinions on medical diagnosis and treatment.


I am not medically trained just someone who has struggled to get a diagnosis.


Wow! Thank you so much. So much information to read and get my head around.

I am in the UK.

I understand what you say about 'self-medicating' with b12, I have wondered about this myself. I guess I am just so fed up and just want to feel better, that I thought this was the quickest route. Do you suggest I stop?

I did tell the GP that my father has PA, and I was not offered an IFA test. I didn't know of it's existence until I found this forum. I have had several blood tests over the past 6 months for ferritin and b12, and a full blood count (FBC). The last FBC was two weeks ago, and the GP says there was nothing "untoward" in the result. I do not know exactly what the results were, unfortunately. If I ring the GP receptionist and ask for them, will they give them to me, or will I have to see a GP first?

"Have you had a blood smear/blood film?" - No.

The GP has not considered anything else. I mentioned in my post that I am perimenopausal. That is originally what I have seen several GPs about in the past 6-8 months, but on reading up the low b12 symptoms appear to match many of the peri symptoms too. The GP I saw last picked up on the low b12, and told me that the test that another GP had ordered just after Christmas (and she had told me was 'fine') was in fact borderline (at 190). He asked me to have another b12 and ferritin test - hence the recent diagnosis of iron deficiency.

Thank you very much for your comprehensive reply. I will read up.


"If I ring the GP receptionist and ask for them, will they give them to me, or will I have to see a GP first?"

Have a look at the links in my post above, under heading "Access to records"

Some GP surgeries have online access to a summary medical record. Your GP surgery or perhaps their website should be able to tell you more about this. It is a summary and may not have all the info you want and some GP surgeries do not yet offer online access.

"I did tell the GP that my father has PA, and I was not offered an IFA test"

Have a look at the BSH Cobalamin flowchart in above post, it gives recommendations about when UK doctors should order an IFA (Intrinsic Factor antibody) test.

Some forum members have found it helpful to write letters to their GPs expressing their concerns (with lists of symptoms, extracts from B12 documents, blood test results).

Things said in an appt can sometimes be forgotten whereas a letter is a more permanent record of concerns expressed and my understanding is that letters to GP are filed with medical records.

This next link may be of use to those want to write a letter to their GPs about B12 deficiency.


The person who runs website can be contacted by e-mail.

PAS membership


Members of the PAS can access details of PAS local groups in UK. These local groups can be a source of info on helpful Gps etc in locality.


Self treatment is a decision that some people make for themselves. My personal view is that it is much better to be treated by a doctor.

"last FBC was two weeks ago, and the GP says there was nothing "untoward" in the result"

As I said above, MCV result on FBC may appear to be normal range if a person has both low iron and low b12/low folate because effects of low iron can mask effects of low B12 and low folate on size of red blood cells.

If you contact the PAS, they may be able to point you to useful information.

PAS contact details in my post above.

One extra thing I learned is that there are local area NHS b12 guidelines . Some of these local b12 guidelines have not been updated since BSH Cobalamin guidelines came out in 2014 so may not reflect BSH Cobalamin guidelines advice.

May be worth trying to track down local B12 deficiency guidelines for your area.

I gave a copy of BSH Cobalamin guidelines to my GPs as I was not sure they had read them.

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Go in and ask the receptionist for your blood results (you are by law allowed them) lean on the counter giving her/him the idea that you are not moving until you get them.

I see that you have had several tests - make a list of the dates and ask for them all.

Choose a time when they are not busy. You can find on the internet when they suggest collecting results, usually between 1.00 and 2.30pm.


That's helpful - thank you. I will read up, and go suitably prepared.

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My understanding is that In UK, a doctor has to sign off requests for copies of blood tests so it may take a few days for them to prepare copies.

I believe the only reason a GP can refuse a request for copies is if they feel to give someone a copy could cause them harm in some way.

Some surgeries may prefer people to submit a formal written request for copies.


Hi HistoryStudent does your doctor know that your father has got P.A?

This is yet another instance where the doctor is looking at his computer screen instead of you, the patient.

The N.I.C.E guidelines on how a doctor should treat a Vitamin B12 Deficiency for people with neurological involvement read:

"Seek urgent specialist advice from a haematologist.

Ideally, management should be guided by a specialist, but if specialist advice is not immediately available, consider the following:

Initially administer hydroxocobalamin 1 mg intramuscularly on alternate days until there is no further improvement, then administer hydroxocobalamin 1 mg intramuscularly every 2 months.​"


Click on the link above then on "Scenario Management"

It is also important that your Folate level is monitored as this and B12 help iron to make red blood cells.

Make a list of your symptoms and present this to your doctor together with the guidance notes and ask him to treat you according to your symptoms and start you on loading doses "until there is no further improvement".

If possible take someone with you who can validate your neurological symptoms as the doctor is less likely to pooh pooh you in front of a witness.

I am not saying that this is an easy thing to do but try to stay calm, write out what you want to say and keep to the script and be confident that you are "in the right" and your facts are correct.

I am not a medically trained person but I've had P.A. for over 45 years so

​I wish you well and hope you get the treatment you need and deserve.


My GP ... said my b12 isn't low enough to treat.

B12 serum test cannot be used as a single measure for deciding treatment - needs to be taken in context with other symptoms and signs - which includes the fact that you appear to have multiple vitamin and mineral deficiencies - implying an absorption problem - could be lowering of stomach acidity - could be PA, Coeliacs, crohn's or drug interactions.

The BCSH guidelines state that symptoms should be followed rather than test results because the B12 serum test will result in 25% of people who are B12 deficient being missed (though will also pick up 5% who aren't) - particularly as you have neurological symptoms - tingling - shouldn't be delaying start of treatment.

Believe sleepybunny has provided you with link to the guidelines.

Whilst high dose oral can be effective in treating an absorption problem it doesn't work for everyone and the doses you are currently taking may not be enough to correct an existing B12 deficiency.


Thank you, Gambit62.

I will read up on all the information I have been given, and take it from there.

Still unsure whether to continue the supplement or not, though!


no harm in keeping the supplementation going (except the expense) whilst you try to get your GP to recognise that they may not be treating you correctly (there is always a chance that it is just iron) though seems unlikely.

Ask if they would look into potential absorption problems. If they will do IFA then you will need to stop supplementing a week before the test - otherwise it may give a false positive


That's useful. Thank you.


Yes, continue to supplement!!

There's no risk from taking it, but great risk to your mental and physical health if you don't!

Looks like you either need a new GP or you need to get the one you have familiar with the info provided above.


I have to be honest that I am pretty unimpressed with the 3 doctors I have seen recently, both for menopause and b12 issues. It does seem that all they are interested in is acute health problems - if you have a longer-term, or more chronic condition, they don't want to know.

I have not had that much interaction with my doctors since I had my last child 16 years ago - visiting the doctor is rather a last resort!

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