Pernicious Anaemia Society
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B12 General and Treatment advice for a Newbie


After nearly 3 months of going in and out of the doctors with the following symptoms I started to wonder if I was B12 deficient:

-numbness/weakness in legs and one arm

-constant faintness/dizziness

- tinnitus

-sore/stiff knee joints

-extreme tiredness


-gastro problems

They ran a B12 test after I displayed macrocytosis on a FBC. The doctor told me my my B12 was normal, and said I just had a virus. He did however instruct me to have another blood test to ensure my blood results went back to 'normal'. After a few more weeks, with the symptoms worsening, I decided to get copies of my blood test results. They eventually handed them over and I had a B12 level of 243 (which I know now is low enough to be deficient in spite of what doctor said) and high folate levels of 13.4 (I understand you can have high folate if your active B12 levels are low as it is essentially redundant!). I was tested for lots of things-thyroid, parasites, iron etc...and everything came back negative. I'm guessing B12 is looking a possible culprit?

To cut a long story short, no less than four GPs refused to give me B12 injections because of my B12 test results. I pleaded, brought printed-off information from the NHS website to consultations. They even agreed with my self-diagnosis but all said they couldn't "justify" injections or that I was not "deficient enough" in spite of my symptoms. I am on my third doctor's certificate because the faintness and weakness is so bad I cannot get up and work. I am more or less housebound. 

I have been taking 5000mcg sublinguals (2 x day) for nearly 2 weeks now. Last week the faintness receded a little but a few days ago it came back as bad as before-and with killer headaches this time. Are headaches at the start of treatment normal? Am I being too impatient to expect any change just yet?

I have arranged a couple of private B12 injections (5000mcg of Methylcobalamin) next week and will perhaps have two more the week after. I cannot afford to pay for any more private injections after this so in the meantime I was going to purchase my own B12 injections and self-inject. Does anybody have any advice on purchasing injections (recommended pharmacies, needle size etc) and dose and frequency plans they tried which worked for them?

NHS slammed the door in my face and I'm desperately fumbling around in the dark here so any comments, advice, suggestions, shared experiences are very welcome!

36 Replies

oh gosh poor poor you - yet another person desperate for help and pushed in the direction of self medicating because there is no help coming from their gp.  What can we all do about this... the  trouble is no body knows about this struggle until they are faced by it.  No one would want the injections for fun!


B12 deficiency is looking like the answer more and more. It came on quite suddenly, completely knocked me out. I feel like I have lost my life and would do anything to feel better-even facing self-injecting! Exactly, nobody requests injections for fun. As somebody new to this the NHS handling was baffling!


Headaches are quite common -particularly with methylcobalamin - they could be an indication that you have problems with methylation and you may find this link interesting

Your folate levels - look to be about middle of the range rather than high if I have the right range.  High folate levels can mask the effects of a B12 deficiency on the blood - ie stop the development of macrocytosis.

Low folate will mean that your body won't be able to fully process the B12 that it has.

Please note that starting treatment to B12 treatment when you have anaemia can result in a potassium deficiency.

Find GPs action a little difficult to understand given that you are being signed off work because of the symptoms of the deficiency.

If you are a member of the PAS then I recommend you contact them as a matter of urgency.  If you aren't then I'd recommend you join and then contact them.  They may be able to speak to your GP and resolve the misplaced reluctance.



Thank you for your reply! I've had a skim through the article mentioned above and I think I have absorbed the following information-there isn't an alternative medication, I should just try to reduce the dose of Methylcobalamin. I am taking 2 x 5000mcg sublinguals a day (but have taken 3 on some days). Will methylfolate (which I'm not taking) cause the same issues as methylcobalamin? I thought methylcobalamin was a pretty pure, just a vitamin which your body recognises so I'm trying to understand why it would cause side effects. I'm still not sure if the headaches are another symptom of B12 deficiency or a result of taking the methylcobalamin.. 

Suffering side effects from a form of B12 seems like having salt rubbed into a wound :/

My folate level was 13.4 (range on my test was 2 - 11.5). Doctor marked this as "abnormal but not clinically significant"

I will make sure I'm eating lots of avocadoes and nuts!

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Hi. I take about 5x5000 methylcobalamin sublingual lozenges daily and sometimes use a spray as well. I noticed small improvements after a few days and have now ordered b12 for self injecting. That's the only thing to do if your gp won't listen, and most don't. 

You can't overdose on b12 as it is water soluble and the excess is just excreted. Some people report feeling worse at first. But remember, if you have been ill for a long time it may take a while to feel better. You need to take b12 for life generally. You may find the spray or patches more useful. 

Many people buy b12 solution onlne to self inject because of doctors ignorance and refusal to treat symptoms rather than rely on blood tests. I think it's cheaper than paying privately. With injections you need to start with a loading dose, every other day until symptoms stop improving if you have neurological symptoms then every one or two months, or when you need it. It's non toxic. 

Can you post your thyroid results on the thyroid forum they are great at interpreting the results. Thyroid patients have problems getting proper diagnosis and treatment too. 

Good luck with everything. :-)


Thank you for the info!

I have had bad headaches and increased dizziness since increasing my dose from 2 to 3 5000mcg sublingual lozenges/day-I am not sure if this is a preliminary 'feeling worse' or that dose doesn't agree with me. On the 2 lozenges, I was sure that the faintness/dizziness was starting to get less intense...

It is significantly cheaper to buy the injections yourself I've discovered, to my relief.

I'll get my thyroid results tomorrow.


There are different types of b12 and some people find other types work better. Try looking at or and 


It does sound as if it is the methyl that is causing the headaches so you might be better trying hydroxo - though don't know that sublinguals are as readily available.

You are likely to find that if you have problems with methylcobalamin you also have problems with methylfolate - okay to try but I'd personally approach with caution.

High folate levels can be indicative that you have a methylation problem as the folate will stay in the blood rather than the body being able to absorb and use it properly.  You could try methylfolate and see what that does for you but do it with caution.

If you do have a methylation problem then that is likely to mean that you will need to take a lot more of non-methylated forms.  The genetic variations tend don't result in a total inability but tend to reduce it by 30-65% depending on which genes are involved and whether you have one or two copies of the variant.

People do vary a lot in which forms they respond to - Methyl doesn't really do a anything for me with depression and anxiety which is why I tend to use hydroxo more.


I'll read up on this a little. It seems a few reasons can cause headaches so I'm not sure which one is causing mine. Everybody seems to favour methylcobalamin as a form of B12 but I have found  some hydroxocobalamin sublinguals..


Do you know what your thyroid levels actually were? The fight for a hypothyroid diagnosis is not dissimilar to that for B12 deficiency - "in range" doesn't mean "normal" much of the time.

Not saying it isn't B12 - just putting it out there that it could be both...


I had my thyroid checked twice (by accident!) and they said 'normal' both times but perhaps it is worth checking that-especially after my B12 debacle..

I'm not sure I could stomach another battle with the NHS though...


I know, it's not easy.

But yes, do double check. Make sure they did a proper thyroid check too - that they tested antibodies and FT4 as well as TSH. Often they *only* test TSH and that doesn't really tell you much at all. But if they did only test TSH be aware that anything over 2.0 isn't actually normal.

I'd say "make sure they tested FT3" as well, but that's pretty unlikely - labs have a real aversion to testing it.


Thank you for the tip-I had no idea about this...:/


My pleasure. If you need more thyroid help - and hopefully you won't - feel free to post any thyroid blood test results you have on the Thyroid UK forum here at Healthunlocked:



Just wanted to let you know that I self inject 1mg of methylcobalamin 2x a week and I have never gotten a headache from it. But everyone's different. Good luck!


Methyl ampoules are not easy to purchase. I get hydroxycobalamin which is what the gps in uk use from 100 ampoules for 55.90 euros plus 8 euros postage to uk. I do subcutaneous injections with insulin needles from Amazon uk.


I managed to get some from 

Is there a difference between injecting B12 subcutaneously or intramuscularly? Is it down to personal choice?


Personal choice. The IM needles are longer and a lot of people draw up with one needle and inject with a different one. However I do believe that subcutaneous takes longer to get into the system. Entirely up to you!

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Have you talked to the PAS?

 Lifetime membership costs £20. In some cases they can intervene on behalf of members. At the very least, they can point you to useful information.

Have you ever had an IFA (Intrinsic factor Antibody) test? This can help to diagnose PA. its possible to still have PA even if IFA test is negative/normal. the BCSH Cobalamin and Folate guidelines mention Antibody Negative PA on page 29.


01656 769 717

Office open 8am till 2pm every day except sundays. Some changes during holiday periods.

Other UK B12 websites lots of useful info eg section on writing to GPs/Symptoms/testing etc

 "I pleaded, brought printed-off information from the NHS website to consultations"

Did you give GPs any of the following documents?

UK b12 documents

Google "BCSH Cobalamin and Folate Guidelines"

I'd highly recommend reading the BCSH document. I gave a copy to my GPs along with a  copy of Martyn Hooper's latest book. After many years without treatment the NHS is finally wiling to consider that part of my problems are B12 related.

couldn't "justify" injections or that I was not "deficient enough"

The documents above make it clear that people who are symptomatic for B12 deficiency should be treated even if b12 levels are normal range.

B12 books

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

Could it Be b12 by Sally Pacholok and JJ. Stuart

"They ran a B12 test after I displayed macrocytosis on a FBC"

Macrocytosis can be caused by B12 deficiency and sometimes by folate deficiency.

Coeliac disease

Have you ever had a coeliac test? Coeliac disease can affect the gut which can lead to nutritional deficiencies. It is possible to still have Coeliac disease even if blood test is negative.

Coeliac UK  Helpline 0333 332 2033

I am not a medic just a patient who has struggled to get a diagnosis.

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Thank you for all of the info!

I've actually got a copy of the book on order and also joined B12d! I will take a look at the PAS as well. 

I haven't been tested for the IFA (yet). After the NHS refused to help I set about trying to bring my symptoms under control as quickly as possible (I'm incapacitated with dizziness and numb/weak legs at the moment!) Once I'm feeling better I'll go back and request the test, and try to figure why this happened and how to prevent it from happening again. I didn't bring those print offs..but I did explain about being symptomatic-they weren't really interested. The best response I had was from a doctor who 'acknowledged' what I was saying but as she had no specialisation in this area, couldn't comment on anything other than the tests. She offered to refer me-and I will probably go back and take her up on that once I'm up and about again.

I have not been tested for coeliac disease-thank you for highlighting this. It is perhaps also worth requesting this once I can confirm I'm B12 deficient (I don't think I can be 100% certain until symptoms go with treatment!)


Can I ask how you managed private injections? I have same problem with my mum her level was 233 very symptomatic but not low enough for treatment. Ironically her GP has ordered a ct scan to check for dementia, I have had her on 5000 sublinguals and she said she feels a little more with it but I really think she needs injections but don't know where to go.......


A blood clinic in London. I just explained the situation with the NHS and asked how much injections were. We discussed frequency and dose and the lady booked me in. I plan to self-inject and take sublinguals after the loading doses (just waiting for them to arrive). Like many, it gets to a point when you are just desperate to get better as soon as possible.


Thank you for your reply.... We don't like anywhere near London so I shall continue looking.......


A small rant: If you can get sublingual b12 I would take that and skip the injections, private or not.  Your doctor is the odds-on favorite for the least likely source of a reliable and informed opinion on b12 deficiency, hypothyroidism, and metabolic disorders.  (That's true of most primary-care doctors, btw, not just yours.) 

B12 deficiency is rampant.  Its pervasive in older people, it appears to be one of the significant co-factors in Alzheimers, its common in people with metabolic syndrome and diabetes and with various diet-related syndromes like Celiac, FODMAP sensitivity and so on.  The vitamin has been systematically removed from food by antibiotic use in cattle, its absorption is blocked by cyanocobalamin supplementation in grains, and given you can only pick up 1-2mcg a day anyway from your food its very easy to become deficient.  Some of us end up clinically diagnosed with pernicious anemia specifically - which is the loss of intrinsic factor through a variety of causes.  But the answer to the question, "do I have b12 deficiency, clinical or sub-clinical?", is actually pretty simple to figure out: Go to whatever version of Amazon is the closest to your postal code and order a $12 bottle of 1000mcg sublingual methylcobalamin from a reputable source like Thorne or Solgar, take two a day until the bottle is done, and see how you feel.

You may not have *clinical* pernicious anemia, but if you feel better - tingling sort of stops, anemia gets better, appetite improves, etc. - you had at least a subclinical b12 deficiency.  It doesn't matter what your doctor says.  There may be other things as well going on, but the b12 deficiency can easily be fixed.  Injections are one way to get the stuff, but they're in many ways the least efficient, the most conflict-prone, the costliest, the least safe.  To fix b12 deficiency, clinical or sub, you need continuous long-term b12 exposure through sublingual tablets to make any significant difference, not injections whenever some doctor can give you 10 minutes of their time, twice a month.

/end rant.

I understand the NHS is difficult to work with; I have some experience with the Canadian medical system, which is frustrating, obtuse and stubborn as well.  But doctors in all of the English-speaking countries appear to be unwilling to believe that people feel like crap and its their responsibility to fix it.  So you have evidence your b12 is low: take some and see if it makes you feel better.  Don't count on the doctor having an informed opinion.

Also, high doses of b12 (>1000mcg/day) need to be accompanied by magnesium (400mg/day), potassium (200mg or a banana when you take b12) and sodium (to taste), as well as P5P (50mg/day) and methylfolate (400-1000mcg/day).  There's a whole set of pathways in there that get all messed up by the deficiency.  The minerals will help prevent headaches and flu-like symptoms caused by new cell formation, and the vitamins will make the b12 absorption more efficient.   

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Wow! Thanks for your thoughts :)

I understood that the injections were the quickest and most efficient to get B12 into your body? Have I got this wrong or does is vary from person to person? I was going to use injections as the loading doses and then rely on either injections/sublinguals (which I've been on for 2 weeks now)-depending on what works and suited me. 

You've given me food for thought.

I'm still trying to figure out why I'm having headaches (currently suffering!)-another poster has suggested 'methylation' (I hope this disappears or can be 'dose managed'). Some say you get worse before you get better etc..I will try with the minerals before trying a different form of B12. 


I think, personally, the headaches are a result of potassium deficiency.  You can cause potassium deficiency via a dietary change - you aren't getting enough - or because you need potassium and sodium when you build new cells.  But those deficiencies are very common causes of transient headaches.

"Methylation" is kind of a catch-all term for "the methylation pathways that help build cells are suddenly active, whereas before they were sluggish."  If you don't have all the raw materials for building cells you're going to scavenge them, especially if you're in a starvation state for a particular vitamin.

I don't think injections are the most efficient way to get b12 into your body.  All of the options intend to put the vitamin into your bloodstream first.  But most of the vitamin doesn't make it to your liver, which can only pick up between 1-5mcg a day anyway.  So if you put 1000mcg into your bloodstream via injection or sublingual tablet, most of it won't make it into your liver.  

(I've read some people say that the nerve assemblies will pick b12 up from the blood stream, which would be great if it turns out to be true.  Sometimes it feels true.  But even then its getting it into the blood first that's required.)

So if you need to get it into your bloodstream, what's better: One injection weekly or two tablets daily?    

Its a long game, to refill your liver, rebuild myelin, and revamp your blood.  Your average red blood cell lasts 120 days or so; that means a monthly injection protocol gives you only three injections before you've replaced those blood cells. You could have flooded yourself with b12 by that time, made sure your marrow had all the b12 it needed, and didn't need to share it with all the other possible uses.  

So many people on this board do monthly or weekly injections and feel subpar, and I myself did the same for many years.  It wasn't until I started doing the research that I realized that:

(a) sublingual just means more exposure.  You can take two or more sublinguals a day for years.  If you feel anxious you can pop them continuously.  What's the equivalent number of injections?  Can you do two or more injections a day for years?

(b) most injections use the cyanocobalamin form of b12, which is the shelf-stable version of b12, and which is just bad news.

(c) how expensive is a bottle of 1000mcg sublingual methylcobalamin tablets vs. the equivalent quantity of injectable b12?    

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Sorry, but there's a lot of nonsense here.

Just one example - 

most injections use the cyanocobalamin form of b12, which is the shelf-stable version of b12, and which is just bad news.

I guess you're in the US. Because in most of the world hydroxocobalamin is the most common form of injection.

Why is cyanocobalamin 'bad news'?


The entire premise of cyanocobalamin supplementation, from the beginning, has been that (a) it supplements b12 in healthy people (the supplementation program was never even designed to help pernicious anemia) and (b) the doses are small enough that people won't get too much cyanide, where that dose is in the <100mcg/day range. Neither of those criteria are true in the case of people with pernicious anemia.

People with PA will often be deficient in the stuff needed to separate out the cyanide and convert the result into methylcobalamin. Its hard enough to build new nerve cells with straight methylcobalamin and all the other stuff you need; adding in the additional hurdle of converting cyano to methyl and handling the cyanide is pointless. PA sufferers are also significantly more likely to take very high doses, especially in the UK where "more is better" thinking appears to rule and 5X5000mcg daily doses are common.

So the basic caveats that attended the thinking on the cyanocobalamin supplementation program get blown away by your modern pernicious anemia sufferer. People with pernicious anemia who take cyanocobalamin are (a) not baseline healthy, and thus deficient in several of the agents needed to convert cyanocobalamin into its active form, and (b) also taking very large doses, and thus loading themselves with more cyanide than the supplementation regime thought healthy.

You may want to do some research on the history of B vitamin supplementation. That'll help clear up some confusion.

Second, as you note "most of the world" uses the other shelf-stable form of the vitamin, hydroxocobalamin, and its only here in the savage wilds of America that we forage the Amazon for sublingual methylcobalamin tablets. Hydroxo is reported to cause less discomfort in some people than straight methylcobalamin supplementation. I'm curious if you've ever thought through why that might be. Because - as we all know - its just a basic biological fact that hydroxocobalamin has to be converted into methylcobalamin before the cobalt can be used. Period. End of story. There's is nothing magical about hydroxo that allows it to bypass the conversion queue; use of b12 requires more than one substance anyway, and hyrodoxo requires more than methyl, so its behind the methyl in the queue b/c methyl inserts right into the cysteine cycle.

So why would use of large doses of hydroxo cause less discomfort than use of large doses of methyl? The large doses of methyl are hogging all the resources, after all, which can lead to keto-flu type symptoms, where people become deficient in potassium and sodium, and/or a whole host of other problems like glutathione deficiency. But the hydroxo doesn't cause that - or not as bad - because most of the hydroxo is not being converted into methyl. And that means that with large doses of hydroxo people are throwing most of it away, because they can't convert it. Hydroxo conversion is acting as a throttle to b12 use in the cysteine cycle.

Now, that's a good thing, practically, because it means that people are only getting as much as they can process, and anything else is just tossed out. This is especially true for the people who think massive doses of b12 in any form will help. I sympathize, and was there myself once.

But its also kind of silly. If the solution to b12 deficiency is to ensure a stable supply, the feast-or-famine approach of large doses of hydroxo once a week or more don't accomplish that. In fact one might even call such a treatment regime "nonsense," especially given that one 500-1000mcg methylcobalamin tablet daily would (a) not require the additional conversion catalyst needed by either cyano or hydroxo and (b) the "flooding" approach causes so much discomfort to many people. (Now, is it many or most? There is of course a statistical difference.) Treating with sublingual methyl daily allows people to slowly ramp up the amount of b12 they can handle, its cheap and self-administered, and it needs the same agents that a non-broken cycle does.

And that's because quite simply methyl is the natural form, and hydroxo isn't, and as a result it takes more work to convert hydroxo than methyl. I'm not sure about you, but it seems to me that getting the effect you want, and avoiding unintended side effects, is the better approach.


Total nonsense. I can't even be bothered to get past the third paragraph, so I'll limit my comments to just two wrong bits.

The amount of cyanide released by 1000 ug of cyanocobalamin is less than that in 5 ml of prune juice.

The natural version of B12 produced by bacteria is, despite what methyl evangelists think, hydroxocobalamin. Even Wikipedia knows that.



And from Wikipedia:

"Cyanocobalamin is usually converted to hydroxocobalamin in the serum, whereas hydroxocobalamin is converted to either methylcobalamin or 5-deoxyadenosyl cobalamin."

That's from the wikipedia entry for hydroxocobalamin.

There's not much point in continuing this conversation.

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Hi edgrover.... The reason I want to get her on injections is mainly the speed in which it you start to recover. I saw mum today and she did seem a little brighter, but when I asked dad if he had noticed any difference he said no! Not really. Mum is hypothyroid and has T2 diabetes, her doctor blames all her symptoms on her blood sugars, and to be fair they are high I have been working on those as well. But they aren't doing anything to help her with that either. I live miles away and work and also have T2 diabetes hypothyroid and B12 deficiency (I'm on 12weekly jabs and sublinguals ) for me using sublinguals is like sitting in a paddling pool where as injections are like swimming in the sea, I don't want mum to spend what little time she has left sitting in a paddling pool!! I don't know if this makes a difference but she has liver cirrhosis caused by her diabetes..... Not alcohol 


You're right to think that injections are better. Partly because they're a sort of slow-release for B12. The stuff you inject doesn't enter the bloodstream immediately, it slowly diffuses out of the injection site. That means you get a continuous low level in the blood - which is exactly what your body needs.

Taking sublinguals means that every molecule of B12 that is absorbed goes straight into the bloodstream. You get a huge peak in blood concentration, followed by a rapid decline.

Dermal patches would be a nice compromise between the two, with the B12 being absorbed over a 24 hour period.

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Nice rant and I totally agree with the principle that anyone who thinks they might be B12 deficient should supplement in some way and see what happens, but unfortunately some of us, myself included, find that methylcobalamin sublinguals simply do not work. 5000mcg per day (Jarrow) did absolutely nothing for me at all. I'll stick with my hydroxocobalamin injections which work very well thanks.

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Me too. Although I did find that I needed to take methylfolate tablets as well. But I'm one of the unlucky 9% homozygous for the 677C>T MTHFR mutation.


I might try to reintroduce methy-B12 at a lower dose at a later date. I was fine on them for a week.


Awful situation for you to be in, you will get lots of advise on this site. I wish you well and hope you feel better soon

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