Pernicious Anaemia Society
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Self-treating with methylcobalamin

Hi. A few weeks ago I started to develop neurological symptoms (nominal aphasia, balance problems, inability to concentrate/focus, short term memory problems etc.) on top of a whole range of other symptoms I have been experiencing for some time. These include pins and needles in my hands and feet which I have had for a number of years and now realise are also neurological symptoms.

I have autoimmune thyroiditis which is being treated with levothyroxine and have also been diagnosed with fibromyalgia. My GP has consistently put my symptoms down to these two other conditions but the onset of new symptoms prompted me to ask her to check my B12 levels as well as my thyroid function. The B12 result came back as 400pg/mL - no action required. (I had had a B12 test twice before - one came in at at 300 and one at 400). Having done some research, I decided to begin self-treating and have been a taking a high dose methylcobalamin sublingual spray for over a month now. There has been a significant improvement in all of the neurological symptoms except the paresthesias over the last month and I am generally feeling a bit better. My GP knows about all of this and seemed bemused given that my B12 level is 'in the normal range'! She was happy for me to continue self-treating and did not offer any further treatment or tests.

My question is what dosage of methylcobalamin should I be taking? I started with 1200mcg a day and have recently increased to 2000mcg a day. I am keen to get my B12 levels up to the top end of the normal range as there is evidence that this can help with absorption of levothyroxine and I am not happy with my TSH level which is currently 3.2 (too high for me but again in the so-called normal range) Also given that I do still have neurological symptoms as well as a range of other symptoms which could be attributed to B12 deficiency , should I be pressing for B12 injections instead as per the NICE/BNF guidelines?

14 Replies

Hi Kait, I started out with a B12 at 376 back in August. I started on a low dose B12 tablet initially which seemed to help with my memory and concentration. I increased to 5000 via a sublingual spray when I read that it could help with my bursitis (which has now cleared). My paraesthesia only developed about 6 weeks ago and my GP refuses to acknowledge I have any deficiency (my last B12 serum level came out at 1400+ as I was already supplementing) so I opted to self inject and very slowly the paraesthesia is clearing. It seems to be a very individual thing as to what symptoms are experienced and what dosage is needed to relieve those symptoms - the best you can do is to take as much as you need to relieve your symptoms. I too have autoimmune thyroiditis and my TSH is now coming down. I'm hoping that once that's under control and my neuro symptoms have receded that I can go to a maintenance dose of the injections.

I'm sure there will be plenty of better informed advice following shortly but just thought I'd put in my 5p worth in case it helps.


Thank you so much for responding, Hunny. It seems as if the injections have helped you more than the sublingual spray. Out of interest, did you have any side-effects from the spray? I gather some people do and I have noticed that since increasing the dosage, I have been suffering from severe bloating (I have had this symptom for some time but it has worsened significantly) and mild nausea. I am currently thinking about seeing a private doctor in my area who is much less number-driven and will teach you to self-inject. It will be expensive but worth it if I get the treatment I think I need. He also prescribes Armour which I have been wanting to try for a very long time as I don't do that well on levothyroxine. How did you get into self-injecting B12?


I have also suffered from severe bloating and nausea. Didn't know it had anything to do with P,A. But after 3 visits to 2 different gastroenterologists, I have been told that as a P.A. patient I should assume that I have low or no stomach acid(produced in the same cells as the Intrinsic factor which are attacked by the antibodies that P.A. patients have.)This causes the bloating,(as the food is fermented instead of being digested).which I have more or less eliminated with probiotics, including fermeted vegs which contain probiotics (mostly sauerkraut) I try to avoid wheat also. I drink some grapefruit juice and diluted organic raw cider vinegar with honey every day. It has really changed my life! Perhaps it would help you too. Best wishes.


Thanks for this. I am on probiotics already but haven't tried the other things you suggest yet. Will give them a go.


The best probiotic that I found was SYMPROVE a water-based one Expensive at first, but now I'm on 1/2 dose its more affordable.Took full dose for about 4 months Was so improved that I cut it down!


Having just read up about Symprove online, I have ordered some. Id' never heard of it before so thank you so much for the recommendation.

Best wishes


The only side effect I noticed from the spray was that 10 minutes after using it I was incredibly sleepy and had to crash out for 2 hours. My view is that it's my body telling me that I've given it something it can use to heal and therefore it wants me to sleep so it can use it - I usually feel better when I wake up. I looked into self injecting when the pins and needles on my leg turned into a patch of numb skin and I figured I wasn't getting as much as I needed from the spray/sublingual and my GP, quite frankly, was being an arse. I watched a couple of Youtube videos on self injecting B12 and took the plunge. Haven't looked back since. I saw a response to another post on here which mentioned that nausea from B12 can sometimes be down to the vagus nerve healing - especially if you have digestive issues. I found if I take two sublinguals in a day it can make me feel a bit sick.


That's very helpful. Thank you. How do you source the ampoules etc. for the injections? PAS told me about a private doctor in my area who will teach you to self inject so I was thinking about going to see her but it would be good to know of other alternatives.


Thank you so much for this, fbirder. I am trying to wean myself off H2 blockers which I have been prescribed for GERD for years. Had no idea until very recently that they interfere with B12 absorption and so could potentially have caused my B12 deficiency as well as causing other digestive problems. My GP didn't seem to know anything about the connection. Betaine HCl definitely sounds worth trying.


"The B12 result came back as 400pg/mL - no action required"

I'm surprised the GP didn't treat you. Recent documents make it clear that patients who are symptomatic for B12 deficiency should be treated even if their B12 serum level is normal range.

Has your GP read the following documents? I gave copies of these to GPs.

Google "BCSH Cobalamin and folate Guidelines"

These guidelines came out in 2014 and some GPs/consultants are not aware of them.

It's a very lengthy document but I found it very useful and have quoted bits to my GP. I also printed out a copy and gave it to my GP. I have been told that the NHS is supposed to be following the BCSH Cobalamin and Folate Guidelines.

I was trying to think why your result came back as no action required even though you appear to be symptomatic for B12 deficiency. It could be that the original blood test referral form did not record any of your symptoms or that it did not state you were suffering neuro symptoms.

It could also be the case that your area of the NHS is using outdated regional guideline s for the management of B12 deficiency. Some of the regional guidelines have not been updated with reference to the BCSH Cobalamin and Folate Guidelines. You may be able to find your regional B12 guidelines by a search on your local NHS website or a google search or by a FOI (Freedom of Information) request.

Martyn Hooper, the chair of the PAS has published several books on PA and B12 deficiency. His latest is "What You Should Know About Pernicious Anaemia and Vitamin B12 Deficiency"

I also found "Could It Be B12" by Sally Pacholok and JJ, Stuart really helpful.

pernicious-anaemia-society.... 01656 769467

"I am not happy with my TSH level"

I always felt that some of my symptoms indicated hypothyroidism but because I was normal range I couldn't get treatment. Since I have been supplementing with B12 my TSH has gradually reduced to about 2. The Thyroid UK forum on HU is very active and hopefully can help you.

"given that I do still have neurological symptoms .............should I be pressing for B12 injections instead as per the NICE/BNF guidelines?"

I don't think the NICE guidleines have been updated since the BCSH Cobalamin Guidleines came out in 2014. I tend to use the BCSH Cobalamin Guidelines in discussion with my GP because they are the most recent. the BCSH Guidelines also include details of recommended treatment.

I wish you luck if you decide to ask for injections. I ended up self treating as an absolute last resort after I failed to get NHS treatment and now feel it will be impossible to get NHS treatment because my serum levels are so high.

There are other forms of B12 besides methylcobalamin and various methods of delivery eg patches, sublingual, tablets, sprays. People vary in which ones they respond best to. NHS injections are normally hydroxycobalamin. There is also adenosylcobalamin and cyanocobalamin.


Just to add that the symptoms you describe can be found in other conditions besides B12 deficiency and wondered if you had had tests for any auto-immune conditions/diseases eg Coeliac disease, MS, lyme disease etc.


Hi Sleepy Bunny. Thank you for your very helpful response. I was treated for Lyme disease early last year (despite the test result being negative) when I was really ill with similar symptoms (4 months of antibiotics). Not sure if I actually had Lyme disease or not although there was some response to treatment and I have not been as ill as that since. I haven't been tested/investigated for Coeliac disease or MS. Thanks for the information about the BCSH cobalamin guidelines - I hadn't come across those before. I'm not optimistic about getting injections from the NHS as we have just been through all of this with my son who is more seriously deficient than I am with more extreme neurological symptoms and has only been given five injections despite our challenging his GP with the NICE and BNF guidelines for B12 treatment with neurological involvement. It is all very frustrating and depressing. Thankfully the PAS has been very helpful in enabling us to locate private treatment.


Some more info...

It is possible to still have coeliac disease if results come back negative.


A great resource:


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