Pernicious Anaemia Society

Good news

I've had B12 deficiency caused by metformin taken for Type II diabetes. I saw the GP last Friday and I seem to be successfully reversing the diabetes so she is taking me off the metformin! I've got a B12 injection due this Friday which I want to take. I just wonder how long it will take without metformin before my "natural" levels of B12 stabilise? Many thanks for the help of forum members, particularly when I was first diagnosed a year ago.

4 Replies

That's a good step forward henaddict and hopefully it won't affect your next HbA1c test.

I wish you well.


the body stores B12 in the liver and releases it in to the ileum for reabsorption into the blood so if you don't have any absorption problem now that you are off the metformin then things should start getting back to normal quite quickly. If you do have an absorption problem though (and that is a possibility as the metformin may just have exacerbated a problem that is building up) your ability to store B12 is compromised so you will need to keep on regularly topping it up - but lets hope it is just the metformin.

There are some limits to how much B12 your body can convert to the form that is stored in the liver - so won't be able to use all of the amount that is in the B12 shot - one reason for having loading doses if there is a severe deficiency -

Have you been on treatment for a year now? If so think that you probably do have an absorption problem that the metformin made worse.

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Thanks but the GP wouldn't take me off metformin until I'd reversed the diabetes so this week is literally the first week without metformin so I'm concerned when you say that I probably have an absorption problem?


early days - wasn't clear how long you had been off metformin - thought it was since the point you started B12 treatment - see how it goes.


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