I was diagnosed with B12 deficiency back in January after routine blood tests showed my B12 to be low, and I have been having the B12 injections at my surgery. I was supposed to have had 6 loading doses, one every two days for two weeks, however it was too much too quickly for my body and I had loads of side effects so after 3 of the loading doses my GP stopped them and moved me to one every three months.
My question is, how regularly can you have those injections? The ones every three months have been helpful and I’ve had no side effects, however the last two times I’ve had the injections I’ve been really struggling with fatigue (my main symptom) especially bad in the couple of weeks beforehand so I’ve not been actually getting a huge amount of benefit from them as it’s just gone on helping the worsening fatigue, so my overall baseline fatigue hasn’t actually been helped. As an aside, we are unsure if the fatigue is purely down to B12 deficiency or if it’s long covid as this all started 2 years ago when I had Covid. I also had iron deficiency anaemia at that time too which was corrected, and I also have non alcoholic liver disease so there could well be more than just B12 contributing here.
Sorry for the long post, but I just wondered how regularly you could have the B12 injections and whether I should be thinking about asking my GP for more regular injections to see if that would improve my fatigue levels?
Thank you
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Bookworm1992
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You can try to get your injection every 2 weeks .It may not be easy . I never managed it and therefore I have self-injected weekly for the past 10 years , which is something that you could recourse to if you have no success . Some P.A. patients find that B12 spray between injections helps . I tried this , but it had no effect on me . But we are all different , so you could give it a try . B12 patches I also found useless . ( scientists say that the B12 molecule is too large to pass through the skin)
I know of someone who needs to inject daily . P.A. / B12 deficiency is such a complicated subject . Needs much more research . So in the meantime we have to fend for ourselves to remain viable . We are all different, so will need different regularity of injections.
You cannot overdose on B12 ( unlike many other vitamins and minerals ) This is a useful fact ( my doctor who refused me two-monthly injections said that an extra injection would be TOXIC ! ( Total nonsense of course)
Are you getting enough folate ( vitamin B9) in your diet ? (called folic acid if taken as a supplement. ) It works together with B12 . Take a modest folic acid supplement say 400 mcg if in doubt .
I hope you get lots of replies. It’s always useful and interesting to hear how others manage the condition . Best wishes .
Thank you so much for your reply! I definitely agree it’s so interesting and so helpful to know how others treat and manage this. It’s so sad that we have to push and fight for this treatment that we so desperately need.
I had a months course of folic acid tablets when I was on the loading dose of injections but I might ask about this next time I speak to my GP to see if I need further supplementation.
Don’t expect doctors to be very knowledgeable on B12 deficiency, or nutrition . a doctor that I know said it was all covered on a Friday afternoon in a couple of hours at medical school , with many students already gone off for the weekend .
"I’ve been really struggling with fatigue (my main symptom) especially bad in the couple of weeks beforehand "
I'm not medically trained
If your symptoms are returning before your next B12 injection that suggests to me that you need them more often.
Do you keep a symptoms diary?
Maybe track up to ten symptoms. Score severity daily or weekly. Note any treatment given and any relevant blood tests. Could be useful evidence to show GP of symptoms returning before next injection.
If you have the time and energy, search online for "BNF hydroxocobalamin" . The section on doses outlines recommended treatment patterns for those with neuro symptoms and those without neuro symptoms in UK.
I think you've a chance of getting them every two months if you have neuro symptoms.
Does your GP have a list of all your symptoms? Make sure you include any neuro symptoms.
I used PAS symptoms checklist below and added extra symptoms at bottom of page.
I have concerns about the new guideline ....I feel there's too much emphasis on treating people with high dose oral B12 and I think this could influence the treatment some people are offered in UK.
There has been an increase recently in UK forum members reporting that their NHS B12 injections have been stopped or swapped for high dose oral B12.
This increase was discussed in thread below. I've included links in the thread for those struggling to get adequate treatment.
Maybe you can point out some of the info below to your GP.
1) Pernicious Anaemia Society has a page for health professionals. Health professionals from across world can join PAS as healthcare affiliate members, no charge for them to join.
If you search online for "B12 deficiency Wolffenbuttel" you should find several articles he wrote, including one for Mayo Clinic in US and one for BMJ (British Medical Journal).
As an aside, we are unsure if the fatigue is purely down to B12 deficiency or if it’s long covid"
If your B12 deficiency is not due to diet, I'd expect GP to at least test you for PA and Coeliac disease, two autoimmune conditions that can lead to B12 deficiency.
Coeliac UK have info on diagnosis of coeliac disease.
Worth reading even if you've been tested in past and had a negative result. It's possible for people with coeliac disease to get a negative result in usual test tTG IgA if
1) they have IgA deficiency
Total IgA test is used to check if people have IgA deficiency.
These people need different tests for coeliac disease.
2) they were not eating enough gluten prior to blood being tested
Thank you so much for all of this, so useful! Yes I was tested for PA but my intrinsic factor test came back negative. I’ve also been tested 2/3 times for coeliacs over the past couple of years - latest two months ago - all negative.
Only about half of people with PA get a positive result in IFA test.
Search for these documents online to give you more info on this.
"NICE CKS Anaemia - B12 and Folate deficiency" published some years ago.
"BSH Cobalamin and Folate guidelines" published 2014
NICE published a new B12 deficiency guideline in 2024
I have some doubts about this guideline but I think it's worth reading.
If you haven't done it already, I think it's a good idea to track down the local B12 deficiency guidelines used by your ICB (Integrated Care Board) in England (Health Boards in Wales/Scotland).
If you can't find the local guidelines online, best bet is probably to submit a FOI (Freedom of Information) request to your ICB/Health board asking which B12 deficiency guidelines they are using and for a link to or copy of them.
The thread on tests for PA and B12 deficiency mentions other tests that can help to diagnose PA eg gastrin test and others (link in my other reply)
Thank you so much for this! Luckily my GP told me that the PA test wasn’t 100% accurate, and she didn’t rely on that result to treat me thank goodness!
Yes they’ve been doing IgA and the TTG one. That’s interesting though about increasing gluten consumption prior to the test, I don’t eat much I don’t think to be honest and I don’t really eat bread only occasionally… I will definitely increase this when I have my next round of bloods.
"That’s interesting though about increasing gluten consumption prior to the test, I don’t eat much "
I think Coeliac UK calls it the Gluten Challenge.
It's to ensure that there are plenty of antibodies to gluten in the blood. If not eating much gluten, there may not be enough antibodies to register a positive result in tTG IgA test.
I think this need to eat plenty of gluten prior to blood being tested is also mentioned in NICE guideline for Coeliac disease.
Have you definitely had a "Total IgA test" which checks for IgA deficiency?
If you turn out to have IgA deficiency, you will need different tests for coeliac disease.
People with IgA deficiency cannot make the antibodies to gluten that the usual tTG IgA test checks for.
See Coeliac UK link about blood tests below for more info.
"I’ve also been tested 2/3 times for coeliacs over the past couple of years - latest two months ago - all negative."
If you've been tested several times as GP suspects coeliac disease and your results have been negative each time, I'd expect GP to refer you to a gastro enterologist.
Do you have any strange skin rashes?
Coeliac disease can present as a skin rash called dermatitis herpetiformis (DH).
Although it often shows as blisters, it can also look more like hives.
Thank you, I’ll definitely look into it. I have no other symptoms I think it’s just because it’s different Drs each time and they just want to make sure there’s nothing underlying. Interestingly though I do have a rash on my leg that won’t go so that’s worth knowing, I’ll ask about it, my GP just thinks it’s eczema.
Every eight weeks at my GP surgery, but I need B12 every four weeks so I self inject. Occasionally I need an extra B12 injection, which I do myself. I know the symptoms that tell me I need extra.
Thank you, that’s so good to hear that you can do it yourself and have it when it’s needed. My GP mentioned about self injections but that it wasn’t available yet but I’ll keep asking.. my Mum is a nurse so I wouldn’t have any issues self injecting.
Hi, I haven’t posted on here before because you’re all so kind and helpful that you’ve answered all my questions just from reading.
I started B 12 injections 3 monthly after the loading injections and it helped a little but the fatigue didn’t clear as quickly as my doctor expected. I kept notes and found to back up telling the doctor that symptoms (headaches, loss of feeling in legs, wrists giving way and increasing anxiety) were all better after an injection but then increased from about 6 weeks. After a lot of discussion I was changed to 8 weekly and found the same deterioration from 6 weeks and now have my injections every 6 weeks which has helped a lot.
Thanks to my really helpful GP she also investigated why the fatigue hadn’t eased as expected and found I also had a heart condition. Lots of investigation and I’ve now got a pacemaker which has helped a lot.
I realize I’ve been very lucky with the support I’ve had and dread changes.
That is so good to hear that you’ve been able to work with your GP to get the injections you need and your GP has got to the bottom of what’s going on and given you the support you need.
I’m sorry that you’ve found it hard to get the right level of care. A lot of people with B12 deficiency need to self-inject much more regularly than what is available through the NHS. My GP was only able to offer the 6 loading doses and one injection every two months for me but she strongly supports me self injecting and knows the NHS provision is woefully inadequate for many people. I self inject twice a week now after 8 months of treatment. For the first 6 months I injected every other day. I also take supplements to support my injections.
All the best, I hope you can find stable health soon. It’s such a hard process.
Thank you, that’s so good to hear you’ve been able to get a regime that works. My GP mentioned self injecting but that it wasn’t available yet. I’ll keep asking though.
Thank you so much, it’s so hard because there’s no definitive way of knowing what is actually causing the fatigue - my B12, long Covid or my liver - or all three! So I guess it’s kind of trial and error to see what helps, so all of these replies and info are so helpful to help me to discuss with my GP and work through.
Have you read about reversing out symptoms? When I had the loading doses (6 Injections over 2 weeks) I felt completely wiped out half way through. After reading other people’s experiences I concluded this was more about my body desperately needing the B12, not a reaction against it. I was then put on 3 monthly and the same thing happened after each injection - symptoms would go mad and I’d feel exhausted. It was as if my body would go into a frenzy soaking up the B12 it was lacking. My symptoms then improved but returned around 6 weeks later. I now self inject weekly using an auto injector and gradually my neurological symptoms have gone. Ten weekly is the most frequent GP would agree to, which just wasn’t enough. I had a blurry spot in one eye which disappeared after a few weeks of injections. I find I sometimes need an extra one if I’m travelling or have a cold. Definitely consider self injecting to keep on top of symptoms. Good luck!
Thank you! That’s so interesting re reversing out, something I’ll have to look into… I’ve been fine with the 3 monthly ones but the loading doses made me so poorly I was nearly admitted to hospital hence why my GP stoped them early…
Some folks inject more than once per day! Some do it several times a week, and others less frequently. You can't overdose on it. Any excess is excreted in urine. Huge doses of oral B12 can help some folks but by no means all.
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