Pernicious Anaemia Society
14,640 members10,432 posts

Methyl cobalamin trial

I have used methyl cobalamin for three weeks now: one injection of methyl on a Sunday followed by daily injections of hydroxo cobalamin. I was hoping the methyl would improve my heat intolerance and my fogginess in addition to all other B12 symptoms. (My previous regime was daily hydroxo cobalamin)

Initially I thought I had cracked it. On the afternoon of my first methyl injection I had a window of a few hours when the fog cleared. I cannot remember when I last felt like this – awake - I had forgotten what it was like to feel ‘normal’.

Since then however it has been downhill all the way. All my symptoms deteriorated to a level I have never had before. Others were added to the list; I started to feel very anxious and also suffer faecal incontinence. My gait has become very strange and my mind very muddled. I have been finding it difficult to read and understand text. Heat intolerance has become the least of my problems. The plan was to pursue methyl for the month to give it a proper trial however my wife has vetoed this since I have been so bad.

Has anyone had a similar experience with methly? Do the two cobalamins react badly together? I don’t know what other avenues I can pursue in order to feel more ‘plugged in’ and 'alive' or even what to do to overcome being unable to be in a warm environment, when my body completely shuts down.

I assume this is caused by the damage to my nerves.

I have seven ampules of methy cobalamin left. If anyone can make use of these please message me direct and I will send them to you. B12 is too precious to be wasted.

I am still wondering whether my thyroid could be an issue. Any thoughts or suggestions are welcome.

7 Replies

some people do experience the reactions you describe when using methyl. I am aware of one genetic variant where methyl B12 can cause problems with the rather delicately balanced processes that control recycling of neurotransmiters sending them into overdrive which would result in the sort of symptoms you describe.

I am not aware of anything that indicates that different forms of B12 interact and would cause any sort of reaction.

It is also possible that you have a sensitivity to one of the ingredients in the methyl that isn't present in the hydroxo - so may be worth checking the ingredients.

Unfortunately, also true that thyroid may be involved. Some people have reported that their thyroid medication has needed adjusting after starting treatment iwth B12.


Are you on thyroid meds ? Have you been tested ? So many symptoms can and do overlap with PA and Auto-immune thyroid illness .....

1 like


Really sorry to hear your struggle!

What folate do you take and how much?

Have you tried methylfolate? I need this to make my hydroxocobalamin work.

You may need up to 5000 mcg (5mg) of folate as folic acid or methylfolate per day.

What level of other supplements are you taking?

I become bowel incontinent if I don't have enough gluten in my diet and it's horrible!

Looking forward to hearing back from you, Denise

1 like


[Apologies if this question is deemed as 'hyjacking' the thread. I felt this point could benefit from clarification ;) ]

" Some people have reported that their thyroid medication has needed adjusting after starting treatment iwth B12"

Could you explain this further, please? I take thyroid medication (Levithyroxine) and would be interested to know if you mean 'adjusting' to mean higher, or lower, thyroxine meds might be required if/when B12 deficiency is corrected.

Many thanks

1 like

just summarising odd reports over last few years - think it was generally downwards. would be better to post your question on TUK.

1 like


Thanks - Good suggestion re TUK - didn't think of that ;)

Yes, I would have assumed thyroid meds would be better utilised in B12 deficiency corrected

Many thanks



Thank you for all your comments. Gambit your comment about the genetic side of things I found very interesting although it rather closes the door with regard to using methyl.

My next trial will be reverting back to hydroxo but increasing my folic acid. I currently take 600mg which seems incredibly low compared to the quantities mentioned by deniseinmilden. I will increase to 1000mg for a month, see how that goes and increase on a monthly basis thereafter. Hopefully I will feel some benefit at some point in the future.


You may also like...