I have been self injecting for several years as I was taken off B12 injections and told I didn’t need them, however my symptoms came back and the only thing that makes me feel better is B12. It took a while to work out what frequency works for me, and over the last couple of years I have found once a month works well for me. However I gave myself an injection just over a week ago, and really wish I hadn’t as I felt perfectly fine. A couple of days later I had extreme fatigue, and for the last few days I have had tiredness like nothing I have ever experienced before, it’s extreme like I’m on the verge of falling asleep almost. I have never had anything as bad as this before fatigue wise and a few days ago I also had a lot of tingling sensations. I’m scared out of my mind. I don’t know what to do for the best.
Extreme tiredness after B12 injection. - Pernicious Anaemi...
Extreme tiredness after B12 injection.


I've had this at times after an injection but it passes. Levels will plateau hopefully soon and you will pick up again.
Hoping you are not fighting a virus .
Sometimes for me I'm thinking after 3 days or is my perfect level .
I would stick to your regime
Thank you. Yesterday I did wonder if I was coming down with a virus. I will stick to my current regime. I just don’t get why normally I inject B12 and don’t feel like this. I’m worried it could be a drop in my potassium levels?
Only way is to have a blood test .Mine has always been fine .
I was on EOD
For several months .
I've read potassium can drop but mainly in the loading phase .
I do get s surge of ' old symptoms ' if fighting a virus
Or in times of stress
Or dental work.
Anything 'extra for our bodies to cope with.
Have some potassium rich foods .
Have rda multivit perhaps.
I too was wondering whether the tiredness symptoms might be the result of something coincidental to B12 (eg, virus).
Thanks Nackapan. My pottassium level has always been fine, as I have had blood tests when I have been concerned about it before. As today has gone on, it's become more apparent that I am likely coming down with a virus....so that may be why I don't feel well, and have also been fairly stressed recently, so it could be something that sorts itself over time.
I have also had this happen when my folate was low , it may be worth you getting it checked 🌻
I had self inject my B12 every 4 weeks for the last 20+ (cannot really remember how long accurately), and 2 months ago got a similar 'electric shock tingling' all over my body - head, face, arms, hands, legs, feet etc within a couple of minutes of injecting, which lasted about 3 seconds or so. I felt terrible, and for a few days after my balance, speach and memory were all affected. I then noticed that my medication had been changed from Hydroxocobolamin to Neo-Cytamen and the difference in the ingredients were Acetic acid in the latter. My GP marked on my records that I must NOT be prescribed Neo-Cytamen at all and gave a new prescription of Hydroxocobolamin which I have since taken without any ill effects. Has your medication changed recently????
I will get my folate checked.
No, it was the last one in the packet I have been using for the last few months. Worth bearing in mind though. Glad you are now okay!!!
I’m thinking, if you go too long without B12, or for whatever reason that month through stress/illness whatever you use up your B12 more quickly, when you do have your injection that your potassium could drop as your body goes through a healing process, similar to when you first go on it?
I also have slight chest pressure, I have had this before after a long time without B12 and then having too much at once. Really worried. I have contacted my GP surgery, but know that they don’t think I should be self injecting and hard to explain to them why I do. I know that my B12 deficiency symptoms return without it.
I had this extreme tiredness when I first started B12 injections. It was so bad I would have to go to bed. It turned out my potassium was tanking. Once I started on potassium I felt a lot better.
Hi,
I'm sorry to read that you've had a scare.
I'm glad you're going to get your folate checked and I hope your GP will check potassium too.
What about iron and Vitamin D?
Forum members often report folate, iron and Vit D deficiencies as well as B12 deficiency.
Have you had magnesium levels checked?
I'm not medically trained.
Thanks both. I have been diagnosed with a vitamin D deficiency around the same time as I was diagnosed with B12 deficiency all those years ago, and I have recently gone onto a high strength vitamin D tablet, I’m wondering if that could also be depleting my potassium. I’m waiting for a call back from my GP so I’m going to ask for a test for my folate levels, and a renal screen if they don’t suggest it. Personally I think I may have had a drop in my potassium levels as I can’t think of any other reason for my symptoms. I feel like I need to keep yawning and my arms feel tingly as well as brain fog. My other problem is I get a LOT of yeast infections. I think I have issues with Candida as I take over the counter flucanazole almost every month, and now the pharmacy are saying I need to speak to my GP as I have had it so many times. I read on the list of side effects that flucanazole can deplete potassium so now I’m stuck with a yeast infection I can’t treat. I think the Candida and vitamin issues are linked. I have also been taking spa tone to see if that will help, drinking coconut water and eating bananas for the potassium and will consider a folate supplement as well. I just don’t get why this has happened as I have been self injecting B12 every month no problem for a long time until now, although I have had similar problems in the past when trying to get my levels right (that I have posted about on here). It’s frustrating. Plus my GP surgery took me off B12 and that’s why I self injecting as I couldn’t manage without it, however they don’t think I should be and it’s hard to explain to them why I do, they act like I’ve told them I inject crack cocaine when I have good reasons for injecting B12 but can’t prove it as obviously my B12 comes up sky high in a blood test. I was originally diagnosed with B12 deficiency years ago and without B12 my symptoms come back, but trying to convince my GP I need them just makes me look like a nutcase as my levels are sky high because of the injections.
"My other problem is I get a LOT of yeast infections"
I had lots of fungal infections eg athlete's foot, ringworm, dandruff (like a snowstorm) and thrush before I got enough B12.
Lack of B12 can affect immune system.
I cut down on sugar and tried an anti candida diet which helped.
I hope your GP has a plan to help treat the constant thrush.
Might be worth talking to local pharmacist.
Thank you. I tend to take over the counter treatments, normally flucanazole when I get it, and it always works really well. It’s normally just before my period that I get it. Not every month but definitely several times a year. I have also been on nystatin in the past. At the moment I feel like I can’t take flucanazole until my potassium is back up to a normal level (if it is low)
I have the same history with regards to being prescribed injections and then taken off them after several years and so went to self injections. I've had a similar reaction to injections before and noticed that if I upped my folate supplements a bit, I seem to come out of that fog, but I have to be careful because a little folate goes a long ways for me and if I get too much I get jittery. I generally take a magnesium/potassium combo supplement, along with folate (400 to 800 mg a day) , and vitamin D. I hope you get lined out soon!
Thank you. I think if I can just get my blood levels right I’ll be fine.