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Pernicious Anaemia Society
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B12 problems can anyone help

I've been getting b12 injections for 15 years now I'm 34 and don't feel like they work anymore I feel like I need an injection all the time fatigue headaches dizziness etc. I went to my gp I had my last injection 3 weeks ago and got my blood test results today my b12 is at 408 is this still on the low side especially so soon after my injection. I'm going back to see the doctor Tom morn but want to go in with some info before hand about my levels. I currently get the injection every 3 months. Can anyone tell me what b12 levels should be in a normal person and what it should be after an injection etc....please help

22 Replies

Sadly Jabs1511 you are not alone in feeling the need of more frequent injections in the run up to the next one and it is difficult to persuade a "one size fits all" doctor to vary them.

Was your Folate level tested when your B12 was done?

Write a list of all your symptoms and if possible take someone with you who can verify your having them as your doctor is less likely to "pooh pooh" you in front of a witness.

I'm not a medically trained person but I've had the same problem as you and managed to get more frequent "jabs" so I wish you well

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My folate was 3.9 if that makes sense...this is what I'm hoping more frequent injections cause if not I still have over 2 months to go and feel awful. He also said about tablets instead of injections but don't know if they'd be any better or not


That Folate level is "bumping along the bottom" of the range.

There is a complex interaction between folic acid, vitamin B12 and iron. A deficiency of one may be "masked" by excess of another so the three must always be in balance and it works closely with vitamin B12 in making red blood cells and helps iron function properly in the body.

Personally I have taken 1 – Folic Acid 400μg every day for more years than I can remember but the I have cyanocobamalin B12 injections every three weeks for my P.A. which I've had for more than 45 years.

Do you know the cause of your B12 deficiency?

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I am confused, I thought the cyan wotsit ones were discontinued? Sorry. "I know nothing" xD


When my beautiful and lovely Doctor Rosemary Wool (now over 90 and still living a couple of miles away) gave me the diagnosis of P.A. back in 1972 she gave me the option of eating raw liver three times a day or having cyanocobamalin B12 injections every four weeks for the rest of my life.

Whilst I love liver, baked with onions bacon and gravy I chose the injections... :)

Cyano B12 was the only available form in those far off long ago days and it is still the "injection of choice" in the U.S.A.

When hydroxocobamalin was introduced in the 1980s I had an adverse reaction to it so have continued on cyano ever since although I have now "negotiated" with my current doctor to having them down to every three weeks.

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All I was told at the time I was 19 when o was diagnosed was that if got it because my dad has it and has had it since he was young.. so the b12 result of 408 and folate of 3.9 3 weeks after my injection is still on the low side isn't it


Ask to be tested for methylmalonic acid (MMA). This is a chemical used up in one of the reactions mediated by B12. If you don't have enough B12 getting into your cells then the levels of MMA will be high.

Get tested shortly before your next jab.


Thankyou I'll ask


There are a number of other conditions that have symptoms that are very similar to B12 - including thyroid, diabetes - so possible that something else is actually going on and would be good to rule that out.

Unfortunately there is no established normal range that applies to what happens with serum B12 levels after receiving B12 shots as it introduces another factor into the mix that increases the variation between individuals even more. If serum B12 will miss 25% of people who are B12 deficient before shots are introduced into the mix then it will is likely to miss a lot more afterwards.

Treatment post loading doses shouldn't be based on serum B12 results - it should be based on symptoms.


Ah ok thankyou and I've had tests for thyroid and diabetes etc all came back clear

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Do you have copies of your thyroid results with ranges ? Low B12 and Low Thyroid go hand in hand. The problem diagnosing a thyroid issue lies in the poor testing. Often just the TSH - Thyroid Stimulating Hormone - is tested. You also need the FT4 & FT3 tested along with Thyroid anti-bodies TPO & Tg to rule out Hashimotos. Rarely done in the NHS.

GP's often say *fine* - when they mean *in range* - it is where you are in the range that is so important.

I have Hashimotos and a B12 issue 😊



Hi I am a nurse with B12d your folate is low and my understanding is that folate and B12 have to work together so you need good levels of folate, I take a folate supplement daily, too. Loads of us are in the same boat re B12 injections, I don't know why the hell docs just don't give it , it's less than a quid for god's sake.

That aside, the current (2014) guidelines clearly state that B12 levels don't require to be monitored as "serum B12 rises irrespective of response to treatment" and the B12 test, frankly, is rubbish. Like many others, I had horrid symptoms and my B12 level was around 400. This is because it measure "active" and "inactive" B12 levels and not necessarily what your body is utilising. You need more frequent injections but trying to get that is another story.

Re testing for MMA, you could ask for that. I am not sure of the accuracy of this test. Another is homocysteine but I believe that is effected if you have already had B12 injections - not certain, but think is the case. Good luck 😊


Thankyou I'll let you all know how i get on with the doctor Tom fingers crossed they'll do something

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This old study kept track of MMA levels of patients and is an indicator that less frequent injections might put you in the high normal (borderline) range with MMA. I'll post just the graph w/ dosage and then if you're more interested you can read the full results below from the American Society of Hematology. GL!



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I don't quite understand all that the links u sent but wouldn't less frequent injections put me at risk my b12 would drop even lower and I'd get worse than I am now


Right. MMA reflects tissue availability of biochemically active cobalamin rather than total cobalamin, with an excellent sensitivity. High MMA levels would suggest you might need more frequent injections of B12.


Ok thankyou I get it now x



Are you in UK? I'm asking because patterns of b12 treatment vary between countries.

Do you have any neurological symptoms eg tingling, pins and needles, tinnitus, memory problems, balance issues plus others?




If yes to neurological symptoms,

In UK, people with B12 deficiency with neuro symptoms are supposed to get a loading injection every other day for as long as symptoms continue to get better (this could mean loading injections for weeks even months) then it's an injection every 2 months.

You mentioned you are getting injections every 3 months.

More B12 info

(Some may not apply if you're not in UK)

1) BSH Cobalamin and Folate Guidelines


Flowchart from BSH Cobalamin and Folate Guidelines


2) BMJ B12 article


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

4) B12 books

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

Martyn Hooper is chair of PAS (Pernicious Anaemia Society). Book is up to date with UK B12 guidelines.

"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 book about B12 deficiency with lots of case studies.

5) PAS (Pernicious Anaemia Society)

Some people on forum join the PAS. They are helpful, sympathetic and a good source of info about PA but busy and may not have resources to help non-members. In some cases they can intervene on behalf of members.


PAS tel no +44 (0)1656 769 717 answerphone so messages can be left

Do you have a diagnosis of PA?

Risk factors for PA and B12 deficiency




6) B12 blogs

Martyn Hooper's blog about PA and B12 issues


There is also an interesting blog on "B12 deficiency Info" website.

Unhappy with treatment?

link about writing letters to GP about B12 deficiency




HDA Patient Care Trust

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


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

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"In UK, people with B12 deficiency with neuro symptoms are supposed to get a loading injection every other day for as long as symptoms continue to get better (this could mean loading injections for weeks even months) then it's an injection every 2 months."

I think that's where one of the main problems lies. They're treating us as a group instead of individuals. Reading just this one forum for any amount of time, one can see that we don't all respond the same way to the same treatment. If doctors listened to their patients and monitored test results like they should, many of us wouldn't be in the shape we're in. I'm actually responding very well to oral MethylB12 - 2000mcg daily. And I have serious neurological motor symptoms. Could I do better on injections? Possibly. But someone else might not respond as well using the same treatment or even the same type. It's pretty simple. Listen to your patients, monitor their test results and adjust accordingly.


Well I've just got back from the docs there gonna up my injections to very 2 months been given folic acid tablets and iron tablets...he also said my calcium is low so having a test for vitamin d deficiency...thankyou everyone for your advice



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Good to know GP listened.

Some on forum have got a second set of loading doses.


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