Symptoms and B12 injection side effects

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Hi all,

So finally diagnosed with pernicious anemia after a long time of knowing something wasn't right.

My symptoms over the years were:-

Big toes numb on both feet for a long time - fully investigated at time, they couldn't find a reason.

Cognitive decline in form of memory loss, forgetfulness, confusion, unable to think as quickly. Had a few random periods like this eg can't think of a common word

Freezing cold hands and feet - always thought it was poor circulation- this cleared up within a month after loading does injections

Heavy legs (not fat,) a lot of effort walking - generally thought I was unfit, cleared up after 2 weeks after loading dose- also after each injection on same day my legs felt unbelievably light maybe a bit like jelly. After 2 weeks generally light.

About half an hour after each injection I got shooting pains usually in my feet, hands, then moved on to legs and arms, sometimes just one limb. Prob only lasted about 3 minutes for each one. Felt as if each injection was felt in an area of my body.

Fatigue always complaining and sighing of being tired- many times to the doctors about this one- never got sorted until now. About 2 weeks after loading dose I went for a run, the same distance as before injections, same number of stops, but was not at all out of breath, could talk while running, massive improvement in physical ability in exercise - so was no where near as unfit as I thought I was.

I am now on 2 months after my loading does, my nails have suddenly changed from be dish to very hard, my hair unfortunately is going a bit curly/ wavy at roots, was like this about 15 years ago.

Had bad reaction to b12 injections, had a pimple/sandpaper like rash across forehead and scalp, cleared up after about 6 weeks, was pretty nasty, and I never usually get spots! Used duac cream after 4 weeks that may also have helped.

IBS like stomach problems completely cleared up since injections even slight intolerance to dairy has gone.

Periods have returned to how they used to be a long time ago, always had and been regular but they are much heavier.

My level was 119 when diagnosed, been given hydroxy form of b12.

Never found any with some of my symptoms so thought I would inform others of what to expect with treatment.

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  • Posted

    Also I am still pale but nowhere near as pale as before, noticed difference in face after a week of loading dose, dark circles are much paler. Appear to look more tanned. Might be increase in red blood cells that darkens skin and tanning better.

    Weight stayed the same seem to be more hungry though.

    Will keep updated with any new changes. It has now been nearly 2 month since loading dose. Waiting to see if I will know when need next injections or will get at 3 months if not.

    Not sure if this info will be much help but it would have been useful for me to know if these things are normal as some changes have been unpredicted.

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  • Posted

    Pleased to hear that you were finally diagnosed and feeling overall much better.

    Could you please tell me which particular tests lead to the diagnosis? I am in the processing of having tests as feeling to the point of collapse at times with symptoms typical of pernicious anemia. My blood tests state my vitamin B12 is within the normal range and the doctors don't seem to listen whey I steer them to the fact my Mother was diagnosed with pernicious anemia years ago after becoming gravely ill and tests that failed for 7 months to diagnose her.

    I would be most grateful to know how you were diagnosed?

    Thank you for sharing your experience, it does indeed help myself and others I'm sure.

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  • Posted


    Sorry to hear you haven't been well.

    Yes I also had trouble getting it diagnosed. For the past 10 years I went to the doctors for some of problems given above mostly tiredness. I am pretty sure they had done numerous b12 tests that never showed up deficient under 150. not sure what levels were. It's worth noting that although the deficiency is supposed to be under 150, people believe it should be increased to maybe 400. Another reason I believe I didn't get diagnosed was because I took some super dose b12 tablets each 10000 x RDA when I suspected it could be b12 through my own research. Even if I can absorb say 1% of a tablet that is still about 100% RDA from one tablet that prob masked my tests and therefore diagnosis. I guess that's the problem with self treating. Also I was borderline deficient just over for folic acid, I read this also helps metabolise b12 so been taking that too.

    An I forgot to point out my symptom that got me diagnosed my hands were shaking non stop for 2 weeks and it wouldn't stop that's why I got tested.

    It does run in families so could be good chance you have PA. you could either avoid all possible supplements and wait few month to year for it to drop really bad so you have symptoms they can diagnose. Or take your own b12 and folic to enhance it and risk it never being diagnosed. What level is your B12? Are you low but over threshold? Plus everyone is different. What other symptoms do you have? What is your folic acid level? I am not sure if they can diagnose it without a b12 test. However I have heard there is a test that can measure active b12 which would always be less than a typical b12 test, ie you could be in normal range but on this test you would be classed as deficient. Therefore not sure how accurate the b12 test is anyway.

    Hope that you are ok. Don't give up hope.

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    • Posted

      Hi Lynne when I was diagnosed with b12 anemeia I was told the healthy levels are between 180-400 and anything below can effect your day to day life. My levels were 118 and I have been so poorly over the last year even with then injections. I've jus had my bloods done again and it turns out that my folate has dropped now which is why I'm still poorly. I have to take folic acid for that but can take a significant amount of time to kick in . If I were you I'd revisit your docs and ask for another test . It may be coming back as normal because ur taking folic acid , b12 and folate work together so that could be the reason ur results are coming back ok . Stop taking then before ur test an see of it comes back. Just a thought smile xx
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  • Posted

    Hi Lynn. Thanks so very much for your info. I found it very informative. I have only just been diagnosed with PA with a B12 level of 90. I take it that's quite low? 

    start my coirse of jabs tomorrow and it can't come quick enough. I am an active 52 year old and still play rugby so I just hate feeling the way I do and is quite inconvenient to say the least as I just don't have time to be unwell!!

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  • Posted

    hi Lynn.

    just read your post. you must be delighted to have such as fast response. well done you?

    1)could you say what your B12 levels were if you were tested?

    2)are you self-injecting?

    3)how long do you expect to be on the injections?

    i ask cos i have of similar but more severe symptoms & Doc's not interested????


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    • Posted

      Ian yes 90 is very low indeed, hope the course of treatment has helped you? Especially for your energy levels in rugby!

      Caitlin I don't know what my levels are now it was 119 when diagnosed, though I am getting my injections every 2 months, but I am getting small symptoms sometimes now before the 2 months eg tiredness and weird skin sensations. Though I have just had a healthy baby 3 month ago so prob used all my B12 stores...We had been tryin a while and I conceived few months after treatment!

      I get my injections at the GPs, don't think I could self inject!

      I will be getting injections for life every 2 months.

      Is there anyway you can get tested for your levels at the doctors?

      The guidelines they have for limits should be higher as some people get symptoms over the limit, everyone is different I guess!What are your symptoms? Folic deficiency can cause B12 deficiency too so worth trying those too! x


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    • Posted

      Hi, I don't get it now since treatment but only way to explain was I had the odd large patch of skin eg thigh that would feel painfully sensitive like sunburn. Would have it a few days then fade away. Maybe once or twice a month. Just a bit unusual!
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    • Posted

      That's exactly what I'm experiencing at the moment Lynn. Started on my thighs and that's how I explained it to the doctor.  I told him I felt like I was sunburnt. I've had it on my arms too.  I've just started my loading dose of B12 injections.  I'll be having the fourth one tomorrow.  Thank you for replying to me as I know this is an old thread.  I'm glad you're feeling better now. lol
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    • Posted

      Hi lyn,

      I always thought it was linked to my B12 as don't get it now. Maybe once or twice in past 2 years. Well it should improve for you too? I guess it's a sign of very low B12 as neurological. I actually got it  mostly under my thigh which made sitting down awkward and extremely sensitive to hot and cold temps! Good luck with your injections. smile Taking iron intermittently too also helps with tiredness as nearly always borderline anaemic.

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    • Posted

      Yes, that's where I have it too. I always notice it more when I'm driving. Many thanks for getting back to me Lynn.  I hope I start to feel the benefit of the injections soon.  I finish the loading dose on Monday. I'll get some iron tablets too. lol
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