Pernicious Anaemia Society

B12 and folate

Please could I have some help, I have been advised to come here from the Thyroid UK forum as I have Hashimotos. I have symptoms of constipation, tiredness, dry skin, numbness, pins and needles, loss of concentration, depression, memory loss, confusion, tinnitus, dizziness, how often do I need B12 injections with a negative intrinsic factor antibody result? Been waiting 6 months for another injection which I was offered every 3 months. And do I start folic acid before or after starting the first B12 injection? Thank you

Folate 2.3 (2.5 - 19.5) GP says only just below range acceptable

Vitamin B12 231 (190 - 900) waiting on B12 injections

5 Replies

Hi Shiki I think it's usually advisable to start supplementing with folic acid a day or so after the B12 treatment begins so can you get an injection arranged quickly?

However, as you already have your test results and your GP isn't bothered maybe you should start taking folic acid now as you are actually deficient .

There is a complex interaction between folic acid, vitamin B12 and iron. A deficiency of one may be "masked" by excess of another so the three must always be in balance.

Symptoms of a folate deficiency can include:

symptoms related to anaemia

reduced sense of taste


numbness and tingling in the feet and hands

muscle weakness


Folic acid works closely with vitamin B12 in making red blood cells and helps iron function properly in the body and your B12 levels are "bumping along" the bottom of the range.

Personally I have taken 1 – Folic Acid 400μg tablet every day for more years than I can remember but then I have regular B12 injections for P.A.

Your doctor should know that your having Hashimoto's puts you at risk of developing a Vitamin B12 deficiency.

I'm not a medically trained person but there are others on here who will be able to give you a better explanation.

I wish you well

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Thanks I have an appointment on Wednesday to get the injection arranged.


a bit confused by some of your statements above ie whether you have actually had a B12 shot or not - I wouldn't advise going any longer if you are symptomatic and you have already waited 6 months.

Negative IFA is a long way from ruling out PA as the cause as it gives false negatives 40-60% of the time.The fact that your folate is below range implies that you probably do have an absorption problem.

If you have auto-immune thyroiditis (hashis) then there is a good chance that you will also develop PA.

If you are UK based and have been diagnosed as B12 deficient and it isn't your diet then you should have loading doses 3x week for 2 weeks, followed by 3 monthly maintenance doses. If you have neurological involvement then it would be loading shots until symptoms stop improving (review at 3 months) then maintenance shots every 2 months.

There are a few absorption problems that can be treated so (in theory) you wouldn't need maintenance shots after you have been treated - mainly h pylori infection. Otherwise it's treatment for life.

As Clivealive says you should start folic acid a day or two after your loading shot - and that should have been the case after your fist loading shot - particularly if you had any signs of macrocytosis.

Do you know if you have problems absorbing Iron as well?

symptoms of B12 deficiency and thyroid problems overlap a lot so possible that your GP may not recognise the symptoms - as do symptoms of folate deficiency.


I had a B12 shot 6 months ago. I have problems absorbing iron as well thank you


You need to go back to your GP and get the treatment that you need.

you can refer your GP to the BCSH guidelines which they can access via the BNF but can also be accessed here

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