Thyroid UK
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Should folic acid supplements be taken when having B12 injections?

My GP has just agreed to my Endo's request that I be given a series of B12 injections. I mentioned to him that my niece, who has ME, is currently having B12 injections and that her ME specialist had recommended that she take folic acid while having the injections, My GP said that he had not heard of the need to take folic acid at the same time and that as my blood tests show that my folic acid level is fine he did not think that would be a good idea because if I start to improve we won't know whether it's the B12 that's helping or the folic acid. Has anyone else been told to take folic acid at the same time as B12 injections?

16 Replies

Yes! There are studies regarding this. B12 and Folate work hand in hand. Thus if you have a B12 depletion or deficiency you may also have a folic acid deficiency. If you supplement B12, it may be a good idea to also supplement with folic acid.

Silky x


Thanks SilkyJ. My folate level last Nov was 11.1 ug/L (4.6-18.7) so it was well within the reference range while my B12 was towards the low end of the reference range at 219 ng/L (197-866) so my Endo felt that a course on injections might help.


You may find that your B12 injections will deplete your folate so supplementation is advisable.

I take daily B12 injections too and also supplement with 400 mcg Folate p/d and my latest folate serum results were in the middle of the reference range, which means I could supplement more.

There is a HUGE study on this which is too much to read here x


B12 and folate certainly work together as advised, especially as the hydrocobalamin (injection in UK) needs to be methylised by folate or B12 useless to body, just excreted. Who said levels "fine"? Doc? Entitled to copy test, check for self folate is optimal, at least 3/4 up range. If decide self-supplement folate, supplement is called folic acid, usually taking max 800 units daily OK. Do NOT take folic acid in isolation, can mask effects B12 deficiency, be careful.



For those with less of a deficiency 5000mcg daily of Methylcobalamin (sub-lingual) might be a better route.

Cheapest I can find currently at Health Monthly, although they are not the fastest or most reliable retailer!


Thanks so much everyone for your responses to my question. I emailed my Endo about this and she said that folic acid is taken to support the formation of lots of new red cells, which may occur when depleted B12 is replenished. She didn't think it was really necessary for me to take folic acid as my level was ok (11.1ug/L, ref: 4.6-18.7) but that it might help and wouldn't do any harm to take a low dose supplement for a short while. She disagreed with my GP who had told me he didn't want me to take both as then if I began to feel better we wouldn't know which was causing that. The Endo said taking some folic acid wouldn't make me feel better but the B12 supplementation should make a difference as stores were low previously. So I'm taking a low dose of folic acid while having the injections. Thanks again.

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I have been prescribed 6 injections of hydroxocobalamin initially over 3 weeks for nerve pains as my b12 is slightly low 137 (range 145 - 569). My folate level is 7.7 (range 4.6-18.7).

My endo says I should take 5mg of folic acid every day but my GP has not prescribed it. 5 mg folic acid is available OTC online. Do you think I should take it.

Thank you


I know that this is an old thread but someone needs to set the record straight. If you have a deficiency (B12 less than 500) then you should be treated. If it is severe due to malabsorption then you should have injections versus pills. There are retrospective studies of experiments on people with PA and neurological involvement who were given high levels of folic acid for treatment. In some cases their nervous systems spontaneously degenerate. The rapidity of the response has led researchers to conclude that this was an unexplained effect of the folic acid rather than an effect from not being treated with B12. At the same time, folate is a required coenzyme with B12 in the methylation cycle. If you supplement with folic acid, I would not take high amounts. If you have neurological involvement, perhaps a better approach would be to initially get folate from food given the unknown consequences of high doses of folic acid with a severe B12 deficiency. After the deficiency is resolved and neurological issues begin to clear, perhaps folic acid is fine. However, in any case, one can get their folate levels tested to provide more information.


That's very helpful. So are you saying that it's not necessary to supplement folic acid when taking b12 supplements? We should get enough folate from our diet?

Sorry to ask for clarification.

My last levels of B12 serum were 240 which isn't very good. But when I take my B12 supplements 1000. I feel very wizzy? Bit hyper? Is that a good thing?

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I don't think it is clear, but I think b12-PhD is saying that a person with low B12 should take folate rather than folic acid.

For help with B12 you would be better to join the Pernicious Anaemia Society community on HU.


I take folic acid with b 12 as iam on chemo at the moment i was wondring why. I seem to have far too much acid now so can. Anyone help me please


I understood that the b12 jabs use folate in the methylation process, b12 may use your reserves. B12 is useless without folate.I have PA and keep my folate topped up with Thornes basic b. 11 may be well within the reference range but it's not optimal I'd like it to be 14/16.

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I am new to this group and have been reading the posts regarding B12. I had a total gastrectomy in July 2017 and 6 rounds of Chemo and been doing B12 injections for the past 6 months (once every month) and started on folic acid since end of Jan 2018. I have numbness in both feet and hands since December 2017. My doctor has recommended that I should take the monthly B12 injections for life. Can anyone say when will the numbness disappear? I understand that it is nerve related, post Chemo, and my Chemo ended since Nov last year?

Thank you.



Hi Kalindeeb54

Welcome to be forum.

It is difficult to say when your symptoms will get better, sometimes they can get worse before better but it also depends on what your b12 levels are?

Did you have them tested before you started the injections ? If so, post the results with reference ranges.

If they were low you should probably have been on loading doses first and then monthly injections.

As above comments show- folic acid/folate is very important too with b12 supplementation.

I would suggest you post a new question on this forum with your own title so more people will see it and advise better.

Make sure you give a short history /test results that you’ve had.

Hope that helps


Hi, Saya85. Many thanks for your quick and very clear response, also the sincere guidance. I will do that tomorrow, as in my part of the world it is late in the night and the family is fast asleep....My medical reports are not at hand....


I am a lady of 63 years old having had a total gastrectomy due to stomach ulcer. 1 lymph node on 14 showed a sign of pervasiveness of adenocarcinoma, so I had 6 rounds of EOX Chemo, which was terribly difficult with its load of multiple side effects. A blood test done on 17.02.18 showed low Platelet count 113 while normal is between 150-400, liver function test results showed high Aspartate Aminotransferase 70 when normal is between 0-40, Alanine Aminotransferase 64 when normal is between 0-31 and Gamma Glutamyl Transferase 129 when normal is between 7-32. Folate slightly high ie., 20 when normal is between 4.6-18.7 ng/ml.

One Doctor recommended that I should have a B12 injection every 15 days and 1 folic acid, 1 multivit and 1 calcium per day, as I do not eat meat, fish or eggs, but take dairy products, pulses, vegs, etc. and I eat small meals due to my surgery.

Given my slightly high Folate, I consulted another Doctor and he recommended 1 B12 injection every 2 months and to reduce the vitamins. I feel alright so I am doing the injection once per month and take 1 multivit and 1 folic acid per day.

Can anyone tell me if I am doing the right thing, Please?

Many thanks.


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