Pernicious Anaemia Society

Methyl not working?

Has anyone experienced IM methylcobalamine NOT working?? I switched from cyanocobalamine about a month and a half ago and many of my PA symptoms have returned: headaches, heart palpitations, and my blood work now shows low level of red blood cells and large red blood cells again. The blood work looks like it did before I started cyanocobalamine injections for my PA!!!! My serum B12 levels are high tho, 2000. I switched to methyl because it's the active form of B12, has no cyanide, is supposedly absorbed better and crosses the blood brain barrier. Could it not be working for me though?

8 Replies

Hi Renee,

There are more people that find methylcobalamin does not work for them, it is only one of the 2 cobalamins the body uses, adenocylcobalamin being the other form, and some people need that as well. I'm putting this very simply, it is far more complex in reality. Also if you are on methylcobalamin you may well need folic acid. Again there are those that do well on the more natural form folicinic acid and others that find it does nothing for them and they benefit from folic acid. Its mine field, you find out by trying what works for you. I use hydroxocobalamin, prescribed, and add cyanocobalamin, I prefer cyano cobalamin as it seems to work much quicker for me. But I have done a year on only cyanocobalamin to find my serum levels dropping by half, so I use hydroxo aswel. Its so different per person. A high MCV can indicate folate deficiency so perhaps have serum folate tested. If deficient your injected B12 will not be used. Both folate and B12 need each other for mtabolisme say so if short on one you will not be able to use the other. A lot of (B) vitamins need each other for uptake so taking a multi vitamin can help make sure you do not have in balances. Also high MCV can be thyroid problem so testing thyroid function and antibodies could be helpful.

If you do well on cyanocobalamin then go back to it is what I'd do.

Some more info in this topic, see:


I hope this helps,

Kind regards,



Thank you Marre. I am going to go back to cyanocobalamine. I'm also taking a coenzyme B complex with folate and adeno in it. in going to dr today and will have her check my folate levels. Thanks again!


Yes. How are you taking the methyl?


1000mg/ 1 ml IM once every two weeks. I live in the US and my dr lets me inject as I feel I need it. I've been under treatment for PA (positive intrinsic factor antibody) for about 8 months.


I've never injected methyl but have tried sublingual tablets and a sublingual spray, neither of which helped me at all even when I was taking 10,000mcg per day. I inject 1mg hydroxo IM fortnightly which works for me. I don't think hydroxo is readily available in the US.

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It was really hard to even get injectable methyl. I had a compounding pharmacy do it and my insurance doesn't pay for it. I'm going to go back on the cyano and try to get my hands on some hydrox nasal stray. Thx for the response! I'm really amazed how different forms work so differently for ppl.


Could you elaborate on how you got ahold of injectable methyl? I'm also in the US and thinking about giving it a try, but I too am noticing that it doesn't seem to be widely available.


I had a compounding pharmacy make it for me. It of course wasn't covered by my insurance and was about 15 dollars per 1ml injection. They mix the powder with saline and alcohol as a preservative. It has to be compounded in a sterile environment and in the dark. They turn on the lights to measure it and due to that small exposure to light, they can't gaurantee the exact strength.


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