Newbie with B12 deficiency and potassium problems

I was diagnosed with B12 deficiency (blood level 197) 4 months ago. Lots of symptoms--dizziness, falling, confusion, difficulty swallowing, ears ringing.

I was told to take 1000mcg B12 by mouth. Over the first 3 weeks, my symptoms got considerably better. But on the 4th week, I suddenly developed severe anxiety, shaking, insomnia and muscle twitches. By reading here and elsewhere on the Internet, I realized this was due to potassium deficiency. Drinking lots of potassium water cleared up the symptoms.

However, whenever i take the B12 for more than a week, I develop the same symptoms of potassium deficiency. i have been eating a high potassium diet--lots of bananas, raisins, coconut water--but it hasn't prevent the reaction, and it is truly awful.

My doctor has never heard of this and doesn't know what I should do. He suggested taking a smaller dose of the B12 in hopes that it would not provoke the reaction.

Is the potassium reaction something I have to endure while taking the B12? Is there an effective way to prevent it? I have no idea how much potassium to use, and my doctor doesn't want me taking supplements.

Any help would be greatly appreciated.

37 Replies

  • Hi,

    I can not realy help, all I know is that to much pottassium is just as bad for you as to little..

    Kind regards,


  • I appreciate your concern. Thank you for responding.

  • OK, I just read something that says B12 can cause hypokalemia in susceptible individuals;

    I think it's something to do with correcting the anaemia caused by B12 - when lots of new red blood cells are produced, then it uses up the available potassium faster.

    The underlying problem could be as much to do with magnesium as potassium - I have heard that potassium cannot be properly stored in the body without sufficient magnesium. I'm going from memory on that one, so you should check it out for yourself. But if that's the case, then perhaps a magnesium supplement would be helpful.

    I think your doctor's advice to take it more slowly sounds sensible. My level was 199 the first time I was tested, but after four weeks of 1000mcg per day I started waking up way too early in the morning, so I dropped back to one or two tablets a week and was able to carry on like that. You will have to find your own tolerance level.

  • This thread might be helpful too:

  • This is tremendously helpful to me. So many people just tell you that you pee out the extra B12 no matter what the dose and that it doesn't give negative symptoms. But we are all individuals and like anything else, I'm sure there are a wide range of doses that people can and can't tolerate.

    The fact that you can get by taking one or two tablets a week is so exciting to me. Has your sleep stayed pretty good doing this? I hate not sleeping, and that was one of the worst symptoms I had with both B12 deficiency and also when taking too much B12.

    Many thanks!

  • I think I had a break of a few weeks before resuming at the lower dose but its hard to remember now. My sleep pattern sorted itself out in that time and doesn't seem to be adversely affected any more. After 3 months, including the high dose four weeks, I was at 297 and after another 3 months 333, so the lower dose is not taking things up very fast, but it seems to be keeping me out of the danger zone. I used to have this feeling that I can only describe as a sense of mental distress, and that has completely gone.

  • When you describe the mental distress, do you mean when you were taking too much B12? Because that's what I have now (I guess I'd call it anxiety) along with not sleeping and muscle twitches. Before I took B12, I had some moodiness along with the fatigue, but that cleared up completely when during the first weeks when I was on B12. Now it seems like I've gone way over the top--at least that's why I think I'm having so much trouble now. Thank you again for your help!

  • No, the mental distress feeling was a problem that I had for quite a long time and which disappeared when I started on the B12. I'd had it for so long it had almost become part of my personality, and it was amazing to feel calm and able to cope again. I'd forgotten what that felt like.

    Anxiety can be a symptom of a number of things and/or the B12 could be just one contributing factor. You end up becoming a bit of a health detective in the end, trying to work out what works for you and what doesn't.

  • Hi I had the same reaction to b12 injection and slept on the drop of a dime now have rapid heart beat and insomnia, never before in my life had trouble sleeping. It's been lil over 2 months. Did ur issues get better?

  • You've been so generous with your advice and time. I can't tell you how much I appreciate it!

  • sharjo it's been a couple of years now hope you are well. I found this thread and think it describes what I go through when I have B12. Keeps getting worse each time, makes me reluctant to take it until I can't stand deficiency symptoms any longer. I eat bananas and drink tons of coconut water but doesn't seem to be of much help. Any advice on how to beat this much appreciated.

  • Hi Tracy, I had the same reaction to b12 shot heart racing and two months of insomnia since. Did you ever resolve your issue w b12? Anything help? Thank you Melissa

  • Melissa, I don't have any hard and fast answers to this. A shot is a huge jolt of B12 so if one is sensitive it does seem reasonable to have problems with a fast heart rate and insomnia. Some use B12 for weight loss as it can act as a stimulant.

    There are some who have an anaphylactic shock reaction, but that is not what I get. I've been told it may be necessary to carry out a desensitation program starting with miniscule amounts administered several times a day for a month or more.

    Currently I'm avoiding any B12 as I'm thinking I could have overloaded my system, which caused my gut nerves to overreact. My B12 was over the maximum amount detectable when last checked so not in danger of becoming deficient for a while. I still get the gut tremors even without B12. Some days I take 1/4 of an Ativan my doctor prescribed for anxiety and it calms down my gut. I'll do this as long as my B12 deficiency symptoms don't return -- sometimes I think symptoms of too much B12 are similar to not enough B12.

    Edit: I don't have as much problem sleeping as I did a couple of months ago. Part of that may because weather is cooler and I don't sleep well when it's hot. Where I live is normally cool in the summer but it's been unusually warm (no one has air conditioning since it's usually not needed). But reducing the amount of B12 may have helped too. I've been using a pill cutter to decrease the amount when I do take some. I also have some B12 lotion and I get a reaction from just a small drop of it. Weird.

  • Thanks for your reply Tracy my dr should have never given me the shot my level was 450, I don't even know why I let him. Anyway I went from sleeping 10 hrs a day to 2 on my own five at most with Zanex or Tylenol pm. Soo weird and no drs know anything. Ahhhh I want my sleep back. How bad was ur insomnia?thanks again Melissa

  • Melissa, at this point I usually wake once at night around 3am and then wake early (6-7am) unless I take something like an Ativan. I've started wearing a sleep mask which helps as my bedroom isn't very dark and I awaken easily when the morning light comes in.

    I am having lots of problems with nerves and palpitations during the day, especially morning hours. Am inclined to think it could be autonomic nerve damage I got from being terribly deficient (affected my feet, can barely walk, now also having gut/IBS issues).

    I just had my B12 checked and it's still greater than 1000 so I don't feel I need to supplement much yet. There's 25 mcg in a multivitamin I take, perhaps I'm absorbing some even though I have PA.

  • Am wondering if "gut tremors" could be from too much B12 stressing adrenals. I used to get that sensation and it was horrid, but mine was from thyroid levels being out of whack.

  • I'm not on this message board much anymore, but thought I'd respond to this old thread. Turns out I have Lyme disease, diagnosed last March. It's behind all my health problems. It really messed up my autonomic nervous system among other things. Starting to mend now, can take years.

  • hi, I face the same problem and got cured with it. Stop taking B12 supplements or foods and just focus on Pottasium rich whole foods only. Having Pottasium will increase the b12 level in the body a little .Also you will have no deficiency with regards to b12. Choose whole foods instead of cooked ones.

  • Hmm I think I suffer from low potassium from celiac. I'm pretty sure when my doctor gave me high dose b12 I ended up with hypokalemia. My potassium is now low normal but I don't feel I hold on to b12.

  • Just seen this post on this zombie thread and felt I had to respond.

    Stop taking B12 supplements

    This is extremely poor advice for somebody with a diagnosed B12 deficiency. It borders on the irresponsible.

    Having Pottasium will increase the b12 level in the body a little

    Nope. It won't increase it at all. Not a sausage. Sweet Fanny Adams.

    If you believe you have low potassium then try swapping regular salt for low-sodium salt. It is 66% potassium chloride. And you'll be lowering your sodium intake as well - which some say is a good thing.

  • I hope you are all feeling better now. Have only just found these posts, as I think I am going through something similar and have been looking for an explanation.

    Can I ask, what form of B12 were you taking?

    I ask because I seem to be OK with injections of hydroxycobalamin, but then had several injections of methylcobalamin and had a very extreme reaction to those - racing heart, difficulty breathing, pins and needles and confusion. Am trying to boost my potassium levels through diet, as am reluctant to take any more supplements at the moment, and think/hope i am making very slow improvement.

  • When taking the methyl form of b12 in an injection my wife had to drink a glass of electrolyte to counter the demand methylation put on the body (higher doses b12)

  • Hope you all solved your problems, but have to ask: are you sure you are not deficient in magnesium as well? Sounds like it with the troubled sleeping. Magnesium works together with potassium!

    Doctors should know that you have to have enough potassium (and magnesium, and probably a lot of other nutrients, like folat) to benefit from the b12 when you have been deficient - and not get worse! Wish they knew more about it!

  • My wife has to drink electrolyte when she takes her methylcobalamin injection. It overwhelmes the body's resources for the methylation process after injecting the methyl form of B12

  • Without the electrolytes, what side effects does she experience?

  • most noticable was pink urine after the shot

  • Ok, thanks. Some of us have really awful physical reactions to methylcobalamin, I was wondering if she had those but they improved with the electrolytes.

  • Go to:, on right side, click on "Preventing methylfolate side effects" , drop down to "electrolytes" heading and read. It talkers also abt methylation side effects.

  • I've been having the same anxiety, thinking I needed yet another b12 shot to fix it, but instead I put my magnesium oil spray on my legs and half an hour later (though it sings of you've shaved your legs!) I fell super calm! I second the magnesium thing to anyone reading this post.

  • It's been a couple of months now and I wanted to know if the magnesium thing worked. I went for 10+ years living in anxiety hell to completely normal 5 days after my 1st B12 shot. I got 6 shots in 7 weeks and at shot #6 I started to experience anxiety again. My system is overloaded. I've been trying to pee the extra B12 out of my system but it has been three weeks now and my nerves are shot. I go to a functional nutritionist tomorrow but I'd like relief now. My blood test showed my potassium on the low side of normal a day after I ate a banana. Did the magnesium spray continue to work? Did you start taking magnesium supplements? Or did eating certain foods work?

  • I messed up my system with too much magnesium! Think I ended up with a b6 deficiency and it stated causing more anxiety. Sadly I'm now back on this same rollercoaster/dilemma of struggling to find a balance, feeling the need to take my b12 right now but a reluctance to go back to anxiety symptoms...

  • Oh, it did help switching to focusing on potassium instead and having lots of coconut water and bananas, my theory is they have about the right ratio of magnesium in them anyway compared to potassium. I'm hoping with coconut water and a sightly spread out dose I can function better and find a balance. I'd like to know what your nutritionist says. Good luck.

  • I have Hypokelemia Periodic Paralysis, and I too had low B 12, however when given a B12 injection, it made my potassium drop so low I was in bed for a day, and felt horrible for several days after that. Going on line and I found that taking B12 injections, does lower your potassium levels. So I ended up taking sublngual B12. However, be careful of that as well, because that can effect your potassium levels as well.

  • I wonder if what many people are experiencing in regards to anxiety and insomnia following correction of B12 deficiency, is an increase in histamine production.

    The way I understand it, when B12 (or copper) are deficient, folic acid becomes "trapped" in its methyltetrahydrofolate form, and begins to accumulate in the body. Methylfolate/MTHF has no other function in our body than to methylate B12 (converting it into methylcobalamin/methylB12), and as the primary storage form of folic acid.

    The hematological properties of folic acid come from its tetrahydrofolate/THF form. This is the form that MTHF gets converted into once it has donated its methyl portion to B12.

    Once freed, THF goes on to play its role in the production of red blood cells (this increases the demand for potassium), and influences the body's ability to retain histidine. This incease in histidine retention will ultimately increase histamine levels, since histidine is the precursor to histamine.

    So, what I think is happening is that following correction of B12 deficiency, histamine levels rapidly climb, resulting in symptoms of insomnia and allergy symptoms (i.e. hives, asthma, sneezing, coughing). And, because of the correction of hematological symptoms, potassium levels begin to rapidly decline, resulting in anxiety, muscle tension, and general feelings of unwellness.

    I wonder if maybe in the case of high histamine symptoms, if supplements that quickly boost the body's ability to methylated histamine might be of benefits? Supplements like SAM-e and methionine. Or, maybe take some of the burden of methyling homocysteine off of the methionine synthase enzyme (the enzyme that uses MTHF to methylate B12), through trimethylglycine/betaine supplementation.

  • I'm not smart enough to understand this... can you break it down for me? I'm b12 and iron deficient - hashimotos - iron and b12 make me go nuts...anxiety, rage, just horrible. But, at the same time I feel absolutely awful.

  • I am in no way an expert, but the anxiety and rage you describe could be do to a drop in serotonin. If my theory is even remotely accurate, the B12 is causing your histamine levels to rise. There is a histamine receptor in your body (can't remember which one) that once stimulated by histamine will stop the release of neurotransmitters like serotonin, dopamine, norepinephrine. Serotonin is like the oil in a car's engine. When low, things start to seize up, get tense, and friction rises.

    One symptom of high histamine would be what a few posters have already described (they start waking up much earlier than they would like in the morning). This is one of the roles histamine plays in our bodies; it wakes us up when light levels start to increase -- i.e. morning sun starts to shine through windows. This is the same reason why some people have "morning allergies", where they wake up congested or sneezing. So, if you are also noticing that the B12 is making it harder for you to stay asleep in the morning, I would definitely suspect histamine as the culprit.

    If you wish to attempt to address the high histamine via supplementation, I would suggest Vitamin C, trimethylglycine/betaine, SAM-E, and if bouts of nausea and diarrhea have also been experienced, perhaps an oral P-5-P supplement.

  • Hello

    I'm having awful problems too, I tried a shot of methyl b12, and felt terrible since, I spent a whole week in bed after the shot, with every single terrible p.a symptom all concentrated down, had a terrible migraine too, really felt like I was dying! Anyway sent hubby to holland and Barrett out of desperation to get potassium, as still couldnt get out of bed, after short while taking it I was feeling much better, statutes supplement it on and off as was worried about taking too much, tiredness and fog came back so had a cyanb12 shot, as reD this isn't as hard on your system, but now feel when I need potassium, heart fluttering and tiredness, take a potassium and magnesium and feel much better, but soooo worried about supplementing with the pottasium, I have no more than 3 capsules of 99mg each, and magnesium is roughly the same, if it makes me feel better then surely I must need it? It's all extremely confusing, and feel l need help before I do some damage, I tried upping potassium rich foods but was not working like the supplement, I bought electrolytes yesterday, are these a safer way than supplements? I'm so relieved there are other people having the same problems as myself, however wish we were all well!!! Please let me know how your now getting on as this post started a long time ago

    Thanx Liz

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