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Thyroid UK
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Different types of B12 question.

I would like to know what the difference is between both types of B12 please?

I have just seen a reply to another poster that recommends using B12 methylcobalamin, reading that made me check mine. Although I thought I had bought the right one, it is sublingual, it lists the B12 as being cyanocobalamin.

Am I making no difference to my levels by taking the wrong type? I am due for a blood test in a few days so will hopefully find out then if it has or has not helped.

Thank you :)

6 Replies


Are you sure cyanocobalamin was suggested and not methylcobalamin? Can you link to that post please.

I've just answered another post asking this question so I will put the information here for you.

This article explains it very well, if you don't want to read it all scroll down to "WHAT IS THE DIFFERENCE BETWEEN METHYLCOBALAMIN AND CYANOCOBALAMIN?"



It looks as if the spell check changed it, I know I wrote down the correct type. (How it managed to do that though is anyone's guess!)

It was your post Susie so I have edited mine. :)


Crikey! cyanide, never would have connected that. That article explains a lot and was very helpful so thank you for finding that for me. x


My 1000 ug B12 is methyl cobalamin.- has kept my levels just above range, so works well under the tongue. It's Nu U which tend to be good value, as long as you read the ingredients.


Further testing of B12 whilst supplementing will skew results. Are you also taking a good B Complex ?

1 like

Yes, Thorne Basic B Marz


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