Pernicious Anaemia Society
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New daily B12 tablet

When I went for my last injection my doctor asked me if I'd like to try a new, daily, high dose vitamin B 12 tablet instead of my injection. I declined because I thought if you can't absorb B12 from your diet then you can't absorb a tablet. It's taken me a long time to get to a stable level and I really don't want to go backwards. Just wondered if anyone else has been offered this or has tried it?

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When I finally got the GP to agree to try helping me she suggested a tablet but as I also have absorption problems I had to explain to her that I thought injections would be best for the same reasons as you. She only agreed to 5 loading doses even though I have neurological symptoms and has insisted on a blood test at the end of them which I think she will use the result of to stop me having any more injections.

good luck!

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Sounds just like the Gloucestershire Guidelines, 5 loading. retest, now normal, retest in 6 months -

Good luck with getting more.


Hi SusieR if it has been established that you have an absorption problem then you are right to refuse tablets. Sounds like a cost cutting exercise to me,

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Link to article about oral treatment on Martyn Hooper's blog

Are you in UK? Do you have a confirmed diagnosis of PA?

The BCSH Cobalamin and Folate Guidelines and the BNF (british national formulary) Chapter 9 section 1.2 make it clear that the recommended treatment for PA is lifelong injections of B12.

I think that oral B12 is recommended for correcting B12 deficiency when it is caused by diet.

BCSH Cobalamin and Folate Guidelines click on "Diagnosis of B12 and Folate deficiency". Think relevant info is about a quarter through document


if you have time may be more useful info in pinned posts on this forum.


Thank you for the link. I am in the UK and was diagnosed with B12 and folate deficiency 7 years ago. Since then I have had regular injections. It took a while to sort out as I started with a loading dose and 3 monthly injections. This initially helped but was short lived and I had another, longer loading dose and then injections fortnightly for a while. These were gradually extended to 6 weeks apart and I have now settled on 8/9 weeks. This works for me. I was never given an official diagnosis of PA but was told this would be lifelong. My diet contains plenty of natural B12 so it is clear I cannot absorb it. Having been reasonably settled for a while I am not keen to upset the balance but was just curious as to what my doctor was offering! He did say it was a high dose and was new. However I have an established routine and I don't want to give him any reason to change it!

I found this online, maybe this is what he's talking about? Anyone heard of it?


Hi SuzieR. Just to let you know, this is not a high dose tablet - 100mcg (and lots of misleading and inaccurate marketing blurb).

High dose would be considered at least 1,000mcg.

B12 tablets currently licensed for use in the UK are 50mcg cyanocobalamin.

Pharmaceutical companies have been asked to develop high dose B12 tablets for UK...but as far as I am aware, these are not available yet.

Be interesting to see what your GP is offering as high dose...



Wow! Thank you, that's very interesting! Pleased to hear you have sorted yourselves with methylcobalamin. Do you buy from overseas?


Cyanocobalamin is NOT bad! The amounts of cyanide contained within it are very, very tiny. To put this in context... may foods have tiny amounts of cyanide in. Do you avoid those too? Your body is designed to cope with these small levels just fine...


my doctor asked me if I'd like to try a new, daily, high dose vitamin B 12 tablet

I would bet pounds to peanuts that the tablet referred to was the old, low dose (50 ug) cyanocobalamin tablet. It's great for people with dietary insufficiencies (i.e., vegans) but about as useful as a fishnet condom for people with absorption problems.


Remember the doctor did not think this up himself. After all he is the guy who is supposed to be treating your symptoms and YOUR HEALTH.


a) about 1% of B12 is absorbed outside the ileum which means that in theory very high doses of B12 taken orally could result in enough B12 being absorbed to maintain your levels but its unlikely to be useful for building up your B12 levels.

You would need to be taking something like 1000mcg a day - which is 4x the RDA

There has been a lot of work in this area so there is a lot of scientific evidence.

Downside is that it doesn't work for everyone - so should be a choice

In the UK 50mcg cyano is the licensed treatment for B12 deficiencies caused by dietary deficiency.

b) There has been some talk for a while of trialling 1000mcg tablets as a treatment option for people with absorption problems as an alternative to injections. So, if you are UK based that would be the thing to check on - the strength of the tablet.

c) In the US high dose oral has been used for some time to treat B12 deficiency - believe the situation is similar in Asia.

d) methyl and adenosyl are the forms of B12 used at the cell level. They are not necessarily the forms taken in in the diet. The metabolism of B12 is complex and requires binding with various proteins at different points in the process. There is a huge amount of processing that goes on between ingesting B12, B12 getting into the blood and B12 getting to the cells where it is needed.

e) most people can readily convert cyano and hydroxo to methyl and adenosyl.

This process can be impaired in people with genetic variations that impair methylation processes but these variations mean that the process is less efficient and more cyano/hydroxo is needed as an input.

f) there are documented incidences of people not being able to convert methyl to adenosyl. Using hydroxo and cyano means that this isn't an issue.

g) hydroxo and cyano cobalamin are both considerably more stable than methyl and adenosyl - a big advantage as it means less chance that they have degraded into forms of B12 that the body can't process in any way such as aquacobalamin.

h) people vary a lot in which forms of B12 suit them best - I find that different forms suit me for different symptoms so actually use a mixture (sublingual and nasal sprays). I find that methyl does absolutely nothing for my neuro-psychiatric symptoms. Others find that they respond very badly to methyl - experiencing heightened levels of anxiety and depression.

There are a lot of genetics involved in the metabolism of B12 so its impossible to give a recommendation of which form is best - people need to be treated as people.

h) the cyanide molecule in cyanocobalamin is very tightly bound to the rest of the cobalamin molecule and it is very difficult to dislodge it. hydroxocobalamin is used as a treatment for cyanide poisoning for this reason.

cyano-cobalamin is safe to use except for people who have very specific and very rare sensitivities (Leber's syndrome) in which case it can lead to blindness - but they will also be sensitive to the amounts of cyanide found in tobacco.

as pointed out above cyanide actually occurs naturally in small quantities in many foods that we eat without a second thought. The cobalamin molecule is so large that the amounts that are going to be freed whilst processing cyanocobalamin as a treatment for a B12 deficiency are within the background levels that we normally take in from food without any harm.


"I was never given an official diagnosis of PA but was told this would be lifelong. "

Did you ever have an (IFA)Intrinsic Factor Antibody test? This can help diagnose PA but is not always reliable.

People can still have PA even if they test negative on IFA test. The BCSH Cobalamin and Folate Guidelines(link above) mention Antibody Negative PA (PA where IFA test is negative) and when it can be diagnosed.

I have heard of people getting a full set of medical records and then finding out that they were diagnosed with PA in the past.

My personal opinion is that a confirmed diagnosis of PA can make it harder for injections to be withdrawn in future which does happen to some people. The PAS can sometimes intervene on behalf of members who have their injections withdrawn.

There are stories about this on Martyn Hooper's blog.


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