My blood levels of vitamin B12 are sky high after I took the injections for almost a year. I don't feel bad or anything just when I did the test at the private lab I was surprised with my result. I stopped with injections but would like to know can too much vitamin B12 cause any health problems? Thanks.
Can you have too much vitamin B12?: My blood... - Thyroid UK
Can you have too much vitamin B12?
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77 Replies
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Are you looking at serum or active levels? You can have high total but it doesn't necessarily mean high active levels...
in reply to TiggerMe
I think serum levels.
helvellaAdministratorThyroid UK
I think this would be far better asked on the Pernicious Anaemia Society forum.
However, it is rare for a lab to actually measure higher levels. They usually have a number above which they simply don't check - typically something like 2000 for a serum B12 test.
Very high B12 when NOT supplementing/injecting can be indicative of other issues. That is why a lab should ask - preferable before testing. But it isn't the B12 that is the problem in such cases - it is what is behind the high level.
I posted this on their forum the other day:
=======
From the draft NICE guidance:
1.6.11 Do not repeat the initial diagnostic test in people who are having intramuscular vitamin B12 replacement.
nice.org.uk/guidance/GID-NG...
Appears to be a very simple statement that is almost impossible to misunderstand.
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in reply to helvella
Yes mine was over 2000. Thanks for the link!
if your B12 is high with injections you probably don’t need to worry about it. Vit B is a water soluble vitamin so what isn’t needed is passed in your urine. Just check your doctor. If you have PA they may recommend stopping injections for now & retest. I’ve had injections for B12 for low levels and I do not have PA.
When I asked my doctor if my low levels were related to PA, she said it's the same thing. How do you know you don't have PA?
there’s a blood test to check for PA. And yes, with injections your numbers will be high. If you feel better keep getting them. I’ve tried the sublingual tablets but they don’t really seem to help. So I don’t know why I’m low. My doc will let me get injections when I want since it causes no harm.
in reply to Crzygirl
No I don't have PA, I was taking B12 to improve my condition on thyroid medications. I got scared when I got my test. Didn't know that it can't do me any harm.
The Nice guidelines say to not retest once on injections. Levels are usually high once you start injecting, it is fine and nothing to worry about. I suggest you resume your injections if they were helping you to prevent symptoms reappearing.
in reply to Hectorsmum2
So relieved! Thank you. I think I will continue with my injections because they were making me feel better.
sonny2,
Welcome to our forum.
Your serum levels will be high because you have been injecting high amounts, presumably due to a VitB12 deficiency.
For variable reasons (usually absorption issues) some people require these high amounts to be able to utilise enough Vit B12 for wellbeing, and if injections have bought clinical/symptom improvements, treatment is best continued.
VitB12 is a water-soluble vitamin meaning excess can be easily excreted. It does not create the same problems as elevated amounts of fat-soluble vits.
helvella has provided a link to the PA forum which is likely more appropriate for your post.
in reply to radd
Thank you. I don't have PA, I need B12 to improve my condition on thyroid meds. It's so good to know that I can continue with my injections because they were making me feel better.
You would not be the only one on the PAS forum who has not been diagnosed with Pernicious Anaemia. Indeed, given the questionable approaches to testing for PA, it is quite possible that even many who think they do not have PA actually do have it. Or a disorder so close that treatment and most other issues, including interfacing with medical staff, is effectively identical.
There is a difference between a B12 deficiency which can be transient or even self inflicted e.g. alcohol induced or eating habits and Pernicious Anaemia .
Furthermore, the scientific jury is still out on whether too much B12 is harmful or not.
A recent conversation my GP had with a haematologist re B12 levels, resulted in the Haematologist saying that despite it being a water soluble vitamin, it can be stored for up to 5 years.
This has something to do with the hormonal properties of B12.
in reply to mauschen
Not much of a drinker myself, don't think it could be due to alcohol in my case. Which food or eating habits can have some impact? Probaby fact that I am vegetarian?
Granny56 in reply to
some spicy food can cause inflammation and chronic inflammation can result in poor absorption.
Being a vegetarian can result in an imbalance of vitamins and minerals if you are not careful to balance your diet. This wouldn’t be malabsorption, more likely to be an imbalance problem easily corrected.
As people get older, they can lose the ability to absorb B12.
Anyone with inflammatory bowel disease could eventually become deficient in B12.
in reply to Granny56
Oh no. I love spicy food. I ate it since I started cooking in my 20's so basically my whole life. I wasn't interested in eating before I discovered spices (dishes my mother made were very bland). Indian and Mexican food is my favourite. Especially indian since it's mostly vegetarian. Didn't know that spices can do that. I wasn't always vegetarian, I became one 15 years ago. My whole life I had a problem with slow digestion, even as a teeneger, I remember I vomited a lot back then because I just couldn't stand food in my stomach. I also can't tolerate garlic or too much onions.
Bear in mind the Cyanokit which contains 5 grams of B12 for infusion.
That is five thousand times the standard injected dose. I'd not be concerned at the levels people get from regular injections - though maybe at some who inject very frequently.
Thankfully, I am too old for a James Bond mission. My levels were 800-900 and I receive my injections of Hydroxycobalamin 1000 mcg every 8 weeks.
My GP consulted a Haematologist because I asked for a 6 week regime due to peripheral nerve pain which became unbearable around week 6.
The response was to change my prescription from 8 to 12 weeks because B12 can be stored in the liver for up to 5 years.
Obviously, I didn’t allow the GP to change my prescription and told him that I had serious doubts about the advice received from the Haematologist .
in reply to helvella
Thank you. I didn't know that. Why is it so hard to diagnose PA?
Years ago, the Schilling test was pretty much definitive.
But it had many issues including the requirement to be administered properly and a small radio-active substance content - and costing quite a lot. However, the actual substance used became unavailable twenty or more years ago for various reasons.
The Intrinsic Factor antibody test simply is not always positive even in those who have PA. Antibodies rise and fall. And if the test is run when they are low, you get a negative result.
Everyone wants a definitive test - ideally one that is simple and cheap.
The PAS forum has many discussions.
in reply to helvella
Thanks for explaining helvella.
The Schilling test was only one part of the investigation. It was couples with a Sternum bone marrow extraction, later changed to Iliac Crest bone marrow extraction.
People with PA do not have intrinsic Factor necessary for absorption by microvilli. Therefore, the Schilling test would determine whether absorption problems existed.
The bone marrow test was to determine the stage of development of the red blood cells which normally live for 120 days. In PA, the RBC life span is much less , having a detrimental affect on oxygen carrying capacity of the RBC.
A combination of both tests along with the clinical presentation such as stomatitis, glossitis, lethargy… were the factors used to make a PA diagnosis.
I get jabs every two months, whenever I've had bloods done, usually checking for blood count, iron levels etc my surgery always seems to ask for B12 as well. They shouldn't do this apparently, my levels are too high to be counted but they exceed the 2000 limit on the lab test.
Then the lab sends a snotty comment back to the surgery along the lines of stop requesting B12 tests for patients on jabs ha ha. I've been on jabs for years so my surgery knows I have them. To answer your question though I've never had any adverse reactions from having high B12.
But there are plenty from having low B12. High B12 levels usually drop slowly if you get enough in your diet. I have PA and am also a strict vegetarian so I need my injections.
in reply to Sparklingsunshine
I am vegetarian too. I don't have PA but I am on thyroid meds and I feel better when my levels of B12 are not low. My blood test also showed over 2000, fortunately I done it in private lab so they won't be informing my doctor or anyone about the result.
mauschen in reply to
It depends on when blood was drawn and when you had your last B12 injection.
A maintenance level of >1000 is expected when you are receiving regular B12 injections.
In order for Thyroid meds to work effectively, you need healthy B12, folate, vit C&D plus Iron Levels as they are all co dependant .
in reply to mauschen
I had my last B12 injection in the morning (I always do them at that time) and the next day I did the test also in the morning.
mauschen in reply to
You will get a better indicator of B12 levels if you test your blood before your injection.
in reply to mauschen
Yes I did that. On the morning I did my test I didn't have B12 injection, so 24 hours passed from the last one.
A day is absolutely NOTHING in terms of seeing B12 drop after an injection.
It takes months for levels to drop to somewhere near what they would be if you were not injecting.
Indeed, this is one reason B12 levels should never be tested once someone is receiving injections. Even if only injecting every two or three months. Reaching the stage of some mythical base level by not injecting for many months could cause severe damage to someone if they really need their injections so it is very rare to see this done intentionally (except in ignorance).
Testing B12 like this is a waste of money, time, thought time considering the results, and anxiety induced.
in reply to helvella
I understand now. It seems that I wasted money on that test and it wasn't even cheap 
Anyway, I continued with my injections in the meantime because I really need them and I am not planning to stop for months so I can have the proper test, it's simply not worth it. I wonder is it the same with people who for example take multivitamin tablets. I mean if they do any test on vitamins or minerals right after they stopped with pills are result fake as well? Or they also need to stay away from them for months just to have the objective results?
mauschen in reply to
Now I am confused. Your previous response said that you did the B12 injection and the next morning did the test. Which is is it?
hi, I spoke to my doctor about this just last week. My B12 results went from 700 to 1476. She told me that it would not harm me to have high B12. However, she did say that maybe they were giving me too much B12. I’m having injections, but she wondered about changing to tablets, I’m due to have a B12 antibody blood test next week to see if my body is either rejecting B12 or not able to process it. But to answer your question no, it will not harm you if B12 is high.
What is this antibody test called?
Sorry I don’t know. The doc just said it was an antibody blood test.
But I will ask when I have it done. That’s if they can get any blood out of me. Previously 6 times of trying - no blood just bruised everywhere for a month before resorting to my left arm which is taboo because of lymph node removal.
I have the same issue lol, it's my right arm missing the lymph node. I had to use it the last time because i have the tiniest veins. I've found that drinking a ton of water in the couple hours leading up helps.
That’s good to know I will try that next time. Dracula has nothing on this nurse. She tried my hand, wrist and arm on right side. My lymph nodes were taken from left side lol. We would make a good pair! 🤣
I was really worried about her taking blood from left arm. I know I have a great vein there but was resistant. My previous doc took BP on left side by mistake and as soon as she did it my hand started to “cog wheel” which resulted in a tremor in that hand and then my right which is permanent. 🙄
oh goodness! Then don’t risk it again. I won’t anymore either. Enough to deal with already!
Bless you, I won’t do it again I have been so careful. But the blood test was the only way this time to get the answers I need. I can’t go on like this. I ate a lot yesterday and still list 1LB overnight! Whoever would have thought that would be a problem. 🤣 all the years of trying and failing to shed the weight gained thanks to being hypothyroid now I don’t want to lose any because I’m too skinny!!!🙄
Sounds like you're hyperthyroid. When I was hyperthyroid I lost 75 lbs in a month. Now I'm hypothyroid, on synthroid 75 mcg, and have to starve myself for days to lose anything.
No I’m not hyperthyroid. My late brother was hyper and he couldn’t sleep and had tons of energy plus the iconic moon face. Although the Endo doesn’t think I’m hyper either we agreed to drop my dosage from 175 to 150. I’ve been on 175 for 30 years and now I’m experiencing the old hypo symptoms from before I was diagnosed. I can sleep around the clock have no energy, get exhausted doing next to nothing and losing so much hair I’m worried I won’t have any left soon. I didn’t wake up until 12.30 today and at 3.30 I was asleep again.
Because the dr found a thyroid lump and enlarged lymph nodes in my neck plus I have hyperparathyroidism it’s possible it could be due to that. Hope not as that means surgery and a trip to ICU as I have difficulty waking up after surgery.
Sorry to hear all that. Good luck.
Thanks I will take all the luck I can get. I am obviously not getting the hint that I’m passed it 🤣
in reply to irishacres
They always have problem when taking my blood. My veins are weak and invisible, even when they find them blood won't come out somehow...
irishacres in reply to
Yep I get that! So frustrating I feel like a pin cushion every time. Nurse said last time I would have to go back and let the hand, wrist, arm heel. No way was that happening. I need answers now!
in reply to irishacres
Exactly! Once they told me to go home and come another time after my arms were completely covered in bruises when few of them tried to stick needles in my veins without any success. I don't think that the problem is only in me, some labs keep completely incompetent staff. And too young and inexperienced I think
irishacres in reply to
Yes I once had the receptionist try to take blood! She said she’d had training when I asked if she was qualified to do it. She tried and failed my hand suddenly filled with blood under the skin. She was mortified and went to fetch a doctor. Poor thing must have told everyone what she had done so they all wanted to see my hand. She was a nice lady and she was put in a position she was not qualified for. It was not her fault. But she kept apologising so much I had to laugh. You would think she had tried to kill me🤣 I think it hurt her more than me 🤣🤣
in reply to irishacres
I lived abroad years ago. Central America. My God they knew how to take blood from any difficult case. Once I asked a young man working there how do they manage it. He told me that when they finished school they exercised on at least 1000 or more of people in their village and around before they were able to get a job in a lab. They don't even leave a trace of a needle when they are finished. I never had that here. Instead, same as you, I had a person who was screaming and running around the hospital in a panic that I am probably dying because my blood wouldn't come out. Believe me she seriously scared me too.
irishacres in reply to
I bet she did!!!! I never used to mind blood tests but dread them now. I’m forever being asked what happened to my hand as there are bruises for weeks.
Maybe you should suggest they do that here before they are let loose on us poor unsuspected people. What do you think the chances are? No I know…..no chance! 🤣
in reply to irishacres
Here?! As you said, no chance 
Post your questions on the PAS forum, they can explain all.
Thanks. I posted on both because I also have hypothyroidism. I probably should’ve mentioned that.
I'd expect it to be an Intrinsic Factor antibody test - but could be Gastric Parietal Cell antibody. Or both!
IFab is good if it comes back positive. But it is well-known that people with PA can have several negative tests and end up being dismissed before being diagnosed.
And GPCab is not definitive for PA.
in reply to irishacres
Thank you. I was really worried. It's good to know that B12 is safe.
Fortie in reply to
Is the nurse using what they call a butterfly needle. Seems to work for me.
I always insist on butterfly paediatric needles. But even those don’t always work.
in reply to Fortie
Yes I think they are better but in my case they usually use them after they already tried with usual needle without success. I always warn them that I have a problem but not all of them are willing to listen.
Just a warning the PA antibody test is notoriously inaccurate and only picks up 50% of cases. So you can get a negative antibody result and still have PA.
Good to know, thank you! 😁 Used to have PA but my current doctor says I don’t have it now!!!?
I'm not aware that it goes away just like that lol. Being as its an autoimmune condition. Its usually lifelong.
Exactly but they are always right don’t you know 🤣
Pernicious Anaemia does not come and go but a B12 deficiency does. PA and B12 deficiency are not the same illness though they receive the same treatment.
I know my doc is useless has no idea how to treat hypothyroidism. He’s taken a week to look into my records to try to decide why I’ve lost 4 stone this year but found a lump on my thyroid. Now wants to see me Monday to check if it’s still there before referring me! It took him a week to work that one out and no idea on weight loss 🤫 Looks like I will have to diagnose myself yet again.
if you look at ReallyWondering above she says drinking a ton of water before a blood test helps. I’m going to try it next time
I was having a big glass of water with half a teaspoon of salt and a teaspoon of sugar every day. That helps to increase blood volume and help stay hydrated. I’ve also increased my salt intake in food.
I am alergic to salt along with loads of other stupid things. Like I said I’m not normal or as my doc puts it “complicated” but I am ok with water 😁
I'm in the 'complicated' club too, symptom wise, no allergies on top though.
Not a great club to be in is it? I can’t remember everything that I have or the meds I take or the consultants I’m under. So I have a spreadsheet for each one and when they ask me I hand them over. Saves a lot of time 🤣 trouble is I’m going on to second pages for each now. I have refused to take any other meds as it’s too much trouble to look up all the interactions!! I think I’m past my sell by date to be honest 😁
in reply to irishacres
Hi irishacres
Feel like I'm past my sell-by-date, too. Noticed I've aged before my time due to illness.
Had a grandfather who died in his 97th year and he said he didn't get old until he was 90yrs.
That's when he couldn't smell or taste food, alcohol and he lost his sexual desire (he wasn't kidding).
But then, he was a very fit & strong man without any diseases. His only health concern was having had two hip replacements.
irishacres in reply to
🤣🤣🤣🤣
Sparklingsunshine in reply to
I had an aunt like that, she was a Land Girl during the war, married a farmer and always lived a rural life, she was still very fit and active in her 90's, I'm sure I heard she did her own decorating lol. Sadly though I think she was the exception, not the rule.
in reply to Sparklingsunshine
Sparklingsunshine your aunt sounds like a real go-getter to the end.
Think you're onto something with the rural life.
Besides my grandfather working in that area all his life, I had two great aunts (not his sisters, on the other side of the family), one who lived to 99yrs (but she'd broken her hip in the 12 months prior -a death sentence at that age) and her younger sister lived to 103 years. Both had lived in rural areas most of their life.
And one (or both) of these great aunts volunteered in the ambulances (on the continent) during World War One.
Oh, and they both ended up owning nursing homes, one of which housed that runaway German.
But I do think that even in rural areas nowadays, our pollution is becoming worse, more obvious. Increasingly black-stained buildings make me shudder at what else is in the air.
Anyways, at least we seem to have more options these days for getting the right treatment.
P.S. Oh, just remembered with the grandfathered who died 97yrs: his records prior to WWII showed he had exceeding low blood pressure. Makes me wonder if he had a touch of thyroid. From what I've read, it's associated with low blood pressure and long life.
If you drink normally you will be hydrated but if you go for a blood test when you haven’t had anything to drink, your veins can collapse.
Years ago, GP would ask for a fasting blood test which meant nothing to eat or drink. Research has taught us that you can drink some water. However, clarify with your nurse what you are allowed. If your blood test is just for B12, then you can eat and drink normally.
Have a glass of water before the B12 test if your veins normally collapse.
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