Pernicious Anaemia Society
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High Level of B12

I recently had a B12 standard test and the results came as follows:

Serum B12 - 2000 ng/l ( Range 200 - 900 U )

Serum ferritin - 344 ug/l ( range is 20 - 300 U )

serum Folate - 9.7 ug/l ( range 3.1 - 20.0 U )

Haemoglobin - 131 g/l ( range 130 - 180 U )

Ten days before the test I started taking Methylcobalamin sublingual tablets of 5000mcg ( 5 tablets a day )

The GP has recommended that I continue taking the B12 tablets but my fear now is that my B12 level is rather high and symptoms still exist.

Is there anyone out there that have his/her B12 at that level, I also noted that my serum ferritin is above the range, is this an issue? as GP never commented on this at all??!!

Thanks for your advice

4 Replies

I have p a and have two monthly b12 injections from nurse however I find the need to self inject subcutaneous weekly to keep symptoms at bay , despite a 2000 b12. You only have 20 % of the total serum b12. Not all that 2000 is active or in your cells. I take folic acid to help get the most from my b12. You can't overdose.


High levels of B12 as a result of supplementation are not an issue.

Pretty sure mine is permanently over 2000 because of the rate at which I need to supplement in order to feel okay.

Persistence of symptoms - given that it sounds as if you have only been supplementing for a few weeks - is probably to be expected. some people find that it takes month before some symptoms start to improve.

When I started treating myself I was suffering from psychosis, weakness, lethargy, depression, lack of balance so severe that I could scarcely walk. I did notice a difference but it certainly wasn't immediate - balance was better by three weeks - depression took 3 months. Your body needs to use B12 to repair the damage which is obviously going to take a while. Its also quite common to feel worse before you feel better - I had a cold a week after starting - runny nose for the first time in years - which I took as being the immune system starting to kick in again - a lot of what we associate with feeling ill is about the body actually fighting infections and if your immune system has been low you will have picked up infections that it will now start to fight properly and clear - rashes/acne are also common.

Everyone is different but you do need to give things time.

Your folate levels aren't fantastic. As the body needs folate to process and use B12 - you might want to look at your diet and see if you can up the amount of folate in your diet. You may not have been deficient in folate when the bloods were done but it is possible that you may have been using a lot in the last few weeks and could be deficient now.

1 like

Mine is that high , more than 2000, they don't record above 2000 so could be anything, without any supplements for years and I am vegan where is it from?

It's hard to find anyone who will explain to me why. My dr shrugs and refuses me b12 injections even though I have had them years ago when my level read 7 . My symptoms are the same as then and now after all my blood tests are complete - evidentially showing nothing - I am taking sublingual b12

that pa society recommended .

I am convinced that I am not utilising b12 I have been in bed 14 weeks , up a couple of hours a day . I'd love an expert opinion and just don't know where to go.



Thank you very much for all what you and other colleagues have said which is very much assuring. I started taking methyl folate soon after I got my results so I hope that will look much better in my next test.

I have gone through all the symptoms you mentioned above which I had overcome, however, the tangling sensation in legs, arms and shoulders still persistent which is effecting my sleep and consequently my energy.

I shall continue on my regime of 30000 mcg of methyl B12 for another 3 months and hopefully feel better before the next test of b12.

Thank you ALL


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