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Pernicious Anaemia Society
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Hi, can anybody tell me if its ok to use cyanocobalamin? I have been prescribed hydroxocobalamin by my doctor which is administered every three months. My levels before my due date are usually around 200 which, from what I can glean from the posts, is still low. I recently bought some cyanocobalamin whilst on holiday but would not use until I was sure it was ok. I will take up the matter of low readings with my GP after my next test but low or not his reaction will be predictable.

Any thoughts?

25 Replies

If you read the responses it gives some potential issues with cyanocobalamin although I would think these issues are rare:


Never tried it but I'm sure others here have and it seems to be the mainstay in USA


Thanks for the link Secondchance will give it a look.


if you have a family history of Leber's disease (an hereditary eye disease) you definitely shouldn't use injectable cyanocobalamin.

Its also not advised to use cyanocobalamin if you smoke because of the effect nicotine has on cyanocobalamin. This may be part of the reason why hydroxocobalamin is used in UK and most of europe in preference to cyanocobalamin.

Hydroxocobalamin is also a little closer to the metabolised form of cobalamin that the body uses and some studies show that some people retain it longer - but the distribution on that is quite wide so a long way from saying that it lasts twice as long for everyone.

Methylcobalamin, which is even closer to the form of cobalamin that the body uses than hydroxocobalamin is probably a better form to use and most people respond better with it, particularly if there are neurological symptoms.


Thanks Gambit62, I bought the Cyanocobalamin whilst on holiday in Turkey it was not expensive. I've never smoked and there is not a history of Lebers disease in my family so would have no qualms about using it from that angle. Is methyl cobalamin available to buy?


You can purchase methylcobalamin sublingual tablets. There is a selection on Amazon. This is a link for information. You cannot overdose with B12 as excess is excreted in the urine.



Thanks for that Shaws, I'll give it a look.


I use cyanocobalamin every 2 weeks on top of my prescribed hydroxo every 2 months now. I smoke. I prefer cyanocobalamin (half the world uses it, it does not sting, is very cheap and stabel), it gives me a much quicker lift (in one day) and less of a stomach upset than hydroxo, but hydroxo raises my serum levels more/ stays in ,my system a bit longer. My serum B12 with every 3 months hydroxo dropped to B12 230 ng/L = 170 pmol/L, I was at that time unknown to me also folate def. With addressing a folate def and increasing the frequency of my B12 (hydroxo and cyano) I now can keep my serum B12 over the 350 ng/L. That is naturally a reading / blood test taken10 days after a B12 jab, as I jab every 2 weeks. I now know I do not recycle B12 trough bile. Some people have more problems with storage and or recycling of the injected B12 it seems. It may help you to have further investigations, see a haematologist, have at least bloods taken to test if you are not now possibly folate and or iron def and try to address any other issues you may have, neurological (see a neurologist) and or gastric (see a gastro) etc. Its what I've done,

I hope this helps,



Thanks Marre some very good info in there for me.


Hope all goes well for you!

There is some good info in this, it explains a little in how some one only using methylcobalamin may still need to also add adenosylcobalamin (AdCbl), whilst hydroxo and or cyanocobalamin will convert to both methyl and adenosylcobalamin if all is going as it should naturally.


Eur J Clin Nutr. 2014 Aug 13. doi: 10.1038/ejcn.2014.165. [Epub ahead of print]

Treatment of vitamin B12 deficiency-Methylcobalamine? Cyancobalamine? Hydroxocobalamin?-clearing the confusion.



Vitamin B12 (cyancobalamin, Cbl) has two active co-enzyme forms, methylcobalamin (MeCbl) and adenosylcobalamin (AdCbl). There has been a paradigm shift in the treatment of vitamin B12 deficiency such that MeCbl is being extensively used and promoted. This is despite the fact that both MeCbl and AdCbl are essential and have distinct metabolic fates and functions. MeCbl is primarily involved along with folate in hematopiesis and development of the brain during childhood. Whereas deficiency of AdCbl disturbs the carbohydrate, fat and amino-acid metabolism, and hence interferes with the formation of myelin. Thereby, it is important to treat vitamin B12 deficiency with a combination of MeCbl and AdCbl or hydroxocobalamin or Cbl. Regarding the route, it has been proved that the oral route is comparable to the intramuscular route for rectifying vitamin B12 deficiency.European Journal of Clinical Nutrition advance online publication, 13 August 2014; doi:10.1038/ejcn.2014.165.

Kind regards,



Ooh, I can't get the whole article!

I have a problem with it! Cyanocobalamin is adeno with the adeno molecule removed. How can it replace adeno?

I have another problem too relating to a musing I have been messing with for about a year.

But I'm not going there with that one.


Hi Poppet,

I can not read the whole article.

As I read it methylcobalamin is only one of the two cobalamins the body converts hydroxo and or cyanocobalamin into. This is the bit that is important for some if they only take methylcobalamin and not adenosylcobalamin, re:"it is important to treat vitamin B12 deficiency with a combination of MeCbl and AdCbl or hydroxocobalamin or Cbl". I do not agree with the whole paper ( particularly the oral bit) but it just was easier for me to paste that than think of it my self say. Some people have a problem with convertion to methylcobalamin, others to adenosylcobalamin and others with both say. So taking only one form can mean incomplete recovery and can explain why some do well on methyl only and others not.

It also can explain why some have only high homocysteine, others only high MMA or both, well in my simplified version of thinking that is. I had homocysteine tested, it was fine, never MMA, perhaps that was not, but I had amino acids tested all mainly to low, methionine to low, I seem to have a problem with carbohydrate, fat and amino-acid metabolism, which may explain why methylcobalamin lozenges did nothing for me, but works for others.

I hope I make sense,



Yes, it does (I didn't agree with the oral bit, either)

I think there is a lot of old ground needs to be gone over with b12 - or the forms of it and how it is metabolised.

Cyano can't convert to adeno because it's had that molecule removed and replaced with cyanide (or that is my understanding of it)

I take methyl but if I add on adeno - I'm not quite sure if nothing happens or if something bad happened ... I had something happen shortly after taking it and I don't know if it was related.

Cyano does nothing for me, at all and of that I am certain.

I've never tried hydroxo and I've actively avoided it because it's got a lot of additives and I don't want them.


What additives? All the hydroxo I've used has contained nothing more sinister than salt and vinegar.


So you've been putting it on your chips?

The ones I saw on line on the data sheets had a fair few bits and pieces in.


I've used Neo-Cytamen and Cobalin-h on UK prescription and Lophacomp, Hevert and Rotexmedica fron Goldpharma and there is nothing in any of them to cause me any anxiety. Multi-dose vials such as those commonly used for cyano in the US tend to contain more nasties than single dose ampoules.

I don't eat chips.


Good job you don't eat chips - you might use it if you got desperate!

I've looked at a couple too and they come up with the same. I know that there used to be extras in the stuff the NHS used because it came up quite a bit in conversation.

I've not got any cyano here to check what it says.


I've been taking hydroxo since May 2006 so it must have been some time ago.

Cyano may be the most widely used form of B12 but I think that has a lot more to do with its stability and the fact that it is cheap to produce than its effectiveness. The data will also be skewed because it appears to be hard to find anything other than cyano in North America.


No, it wasn't before that. But I know there were a lot of additives because that was when I decided to definitely steer clear of the NHS stuff.

I've tried cyano once (2 phials) and it was virtually useless - all my symptoms came charging back.


I've read a lot of comments about additives and it's always puzzled me as I've never been able to find hydroxo that contains any.


I'm just wondering - if yours is German, if they do things a little differently?

I never had the NHS stuff so I don't have anything to hand to compare.


I think they are much keener on such things in Germany but neither of the brands that I've had on UK prescription have contained any additives or preservatives either.


Don't know then. I remember looking a long time ago simply because someone had a reaction and it was suspected it was the additives. But I haven't looked since then. Well, I did, but not for that reason. I just steered clear of it because at the time I was reacting to everything.


Get the chips on.

I've looked at a few and I'm still coming up with salt and vinegar...


I've had a cyano that contained as preservative alcohol benicillico (spell?), and a hydroxo (minedrox), it can apparently cause problems, something fatal gasping syndrome in infants if I remember rightly. The multi vials of cyano can contain (very little) aluminium as preservative apparently.


Thanks, Marre.

It could be that because of the problems it's stopped being used as much now.


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