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Pernicious Anaemia Society
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Mycoplasma related b12 deficiency

I've been tested positive for mycoplasma pneumonia. My b12 came up as 750 but I have symptoms that are very like b12d - high thirst, tingling in hands at night, headaches, blurred vision, bad sleep and fatigue. I was supplementing with sublingual b12 (1mg) and my GP asked me to stop taking it, because it looked like the problem was only mycoplasma. I stopped, but a lot of the symptoms came back or were worse. I started them again and it helps, but I'm not sure how much to take because I don't know which symptoms belong to the b12d and which to the mycoplasma. I took 2mg yesterday and it caused frequent urination which I read it a sign of taking too much. Does anyone know how I can work out the correct dose?

Thank you for your help.

10 Replies

By coincidence I was diagnosed with b12 deficiency when I went to the doctor with Mycoplasma pneumonia,I had an itchy rash for 6 weeks.I insisted that they check my bloods,(again)as I was always sick.when I went back (still scratching and miserable a week later)my bloods were back and my b12 was 174(it was 274 in 2013, 235 in 2011)I was having all my symptoms from 2011.

The thing is ,as far as I've learned the sublingual will drive up your b12 levels on your blood test,and may help you feel a little better(correct me if I'm wrong anyone on here)but it won't repair damage on a cellular level.

So basically you won't get treated at those levels with the doctors,as they only seem to want to treat numbers.

If I were you(and this will be hard)I would stop taking any b12 and get retested in a few months.The fact that the Sublingual b12 helps symptoms would say to me that you are deficient.It doesn't make any sense that the doctor told you to stop taking b12 as its a water soluble vitamin and you can't overdose or do any harm to yourself with it. GOOD LUCK


B12 deficiency lowers your immune system and makes you susceptible to infections.

There are lots of things that can cause frequent urination ... haven't actually come across excess B12 as a factor ... low B12 yes - probably because of the effect on the autonomic system.

If you have high B12 levels then a lot will be filtered out by the kidneys and lost in urine but that's a bit different from urinating a lot.

Was there a reason why you started supplementing B12 in the first place - did you have a blood test that showed low B12. Unfortunately supplementing will skew any test that is done now - and you'd need to stop for 3 to 6 months for a test to be usable.

The levels of b12 that you are taking can correct a minor deficiency as 1% of B12 is absorbed through the gut and you are taking about 600+ times the RDA for B12.

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Hi Gambit62,

Thank you for your reply.

I supplemented because I had a 23andme test which showed I had a double mutation of MTRR A66G. I also had many symptoms of b12 deficiency, many of which went away with supplementing and came back when I stopped. The blood test for b12 was done before I supplemented.

I've just now been reading this site and it talks about many start up problems with supplementing b12 as the body starts to heal. howirecovered.com/active-b1...

I wonder if that was what my symptom was.


I take it that you were supplementing with methyl B12 then.

Quite possible that your B12 serum test came back high because you are absorbing B12 fine but not able to process it into the methylated forms that are used at the cell level - so a test like the active B12 might well have shown you were deficient whilst the serum tests shows you as having plenty.

If you ever did want to get a B12 problem diagnosed though you would have to stop usingthe supplements ... though it would probably be a lot of a battle as GPs and even many specialists aren't very aware of B12 at all.

It isn't possible to overdose on B12 so you don't have to worry about that.

There can be problems with some genetic variations and methylation of folate ... and for some using methylated form of folic acid can be a disaster but I don't think that applies to your genetic variation though it would be as well to approach supplementing anything else slowly just to be on the safe side.

Personally I would take enough B12 to make sure I felt okay. It shouldn't interfere with the mycoplasma ... in fact if it is sorting out your immune system then it should help. Its a bacterial infection.

I find that if I have a bacterial infection or a viral infection then I get through even more B12 than normal as my body needs the B12 to fight the infection.


You might also find this post interesting - and may give you someone to swap experiences with



Thank you Gambit,

For both the link (I'll get in touch) and your reply. Now and again I have had useful help from GPs, but for the most part I've had to get used to doing everything myself and, as you say, I may as well carry on that way. In fact I was just building myself up to increasing the dose, just plucking up the courage, so your post has helped me do that. You're right, the mycoplasma can be removed if the immune system is working properly. The alternative is up to two years of antibiotics!

A few weeks ago I tried doing the high dose thing and it terrified me because it made me feel awful. Now I know that what I felt was because of my body's healing, which also makes me feel much braver. So, here goes and fingers crossed.

Thank you very much for your help.

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I had a cold just a week or so after I started treating myself but felt quite happy about it as it was the first time my immune system had been strong enough to give me a streaming nose for a number of years ... was a bit of a bind as I mainly use nasal spray to get my levels under control.

Go carefully. Sometimes artificial methyl can cause problems and make people feel worse, as I think I said, but its really a matter of try it and see.


Thank you. I will.


Gambit 62:

I know this is a 10 month old post, but just wondering if you are getting everything right here..

In my understanding, Methylcobalamin IS in fact a methylated form, ready for the body to use, unlike Cyanocobalamin and hydroxycobalamin, that has to be processed into a methylated form for us to be able to absorb it. Which means that Mecbl is much easier for those with methylation difficulties.

Besides, here in Denmark, B12 is tested in two ways, of course through blood test, but also testing your MMA through either blood or urine, to see if you raised levels of this. Raised levels are a much more sure indicator of a B12 deficiency, than a blood serum test, as it is only testing the level of your blood cells and not the level of your bodys cells. Dont you have that test available in your country?


Not really sure which thread you are responding. I don't think I said anything that implied that methylcobalamin wasn't a methylated form of B12 or that the methylated forms aren't the forms that are used at the cell level.

MMA is not a standard test in the UK and often has to be pushed for as a diagnosis tool.

In saying that methylcobalamin causes some people problems that comes from individuals reporting this as a phenomenon - there are posts - a number around this time - in which people reported some quite adverse reactions to it but didn't have problems with either hydroxo or cyano. This may be because of methylation problems - it could be something to do with problems converting methyl to adenosyl (there are some reported incidences of that as an issue in the literature) or it could be something else entirely.


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