Thyroid UK

Vitamin b12 dosage

Hi everyone

I am taking a supplement but don't know how much I should be taking to increase my B12 levels - the recommended daily dose is 1ml.

I am taking the Holland & Barrett B Complex Sublingual Liquid - I've heard that H&B products aren't good quality?

Each 1ml drop contains:

B2 - 1.7mg - 121%

B3 - 20mg - 125%

B5 - 30mg - 500%

B6 - 2mg - 143%

B12 - 1200ug - 48,000% - the b12 ingredient is cyancobalamin

I am still getting pins and needles sensations in my left hand and fingers and it seems to have got worse not better?

My B12 levels when tested in May 2015 were 433ng/l (range 220 - 700)

I'm not on any thyroid meds as yet but have managed to get referred to see an Endo through the NHS (long battle)

7 Replies

There is not enough B12 in a multivitamin to make a difference if you are already deficient - you need at least 1,000 mcg of methylcobalamin and, although your serum B12 test result is high, it only measures B12 in the blood and not the tissue and, in any case, is unreliable as you have already been supplementing.

Pins and needles, numbness, etc. are neurological symptoms and should be treated with B12 injections without delay, according to BCSH and UKNEQAS guidelines, as there is a short window of opportunity before symptoms become irreversible.

It might be worth writing to your GP, quoting the guidelines, as well as enclosing this latest BMJ research document, and then taking the summary to your next appointment (in case it is not read) as it emphasises the unreliability of tests and how there can still be deficiency with high B12 levels.

Here are links and an excellent film below, which explain more in case you have not already seen them:

Cmim/BMJ document. " Summary:

* Vitamin B12 deficiency is a common but serious condition

* Clinical presentation may not be obvious thus leading to complex issues around diagnosis and treatment.

* There is no ideal test to define deficiency and therefore the clinical condition of the patient is of utmost importance."

* There is evidence that new techniques, such as measurement of holotranscobalamin and methylmalonic acid levels seem useful in more accurately defining deficiency.

* If clinical features suggest deficiency, then it is important to treat patients to avoid neurological impairment even if there may be discordance between test results and clinical features.

Severe deficiency shows evidence of bone marrow suppression, clear evidence of neurological features and risk of cardiomyopathy.

It is important to recognise that clinical features of deficiency can manifest without anaemia and also without low serum vitamin B12 levels. In these cases, treatment should still be given without delay."

Hope this helps.

1 like

Thank you so much for your time spent on giving all this, Polaris. Really, really helpful. Not to say, disturbing.


I have just read it again. So this could possibly be a reason for "idoipathic cardiomyopathy" ????!!!!! which my brother has.

Looking up from his charts, my brother's cardiac consultant said - perhaps without realising that he was even talking - "So you have idiopathic cardiomyopathy, which will shorten your life - but you also have chronic lymphocytic leukaemia, so that might kill you first."

Oh Polaris! Thank you.


I'm so sorry about your brother Aspmama - that all sounds serious. I would not feel qualified to give medical advice in those circumstances but all I can say is that low B12 and high homocysteine is often involved with heart problems (I believe this is mentioned in the video above) and there have been many misdiagnoses of MS, ME, dementia and psychosis, etc.


Thank you for your response Polaris - I am a bit mystified as been told that my B12 serum is actually too low and not high enough?

The 2nd to last GP I saw noted that my Vit D levels were too low and advised me to dose at 10,000iu a day for 2 months and then 5,000iu a day for 4 months to bring my levels back up again which was great and to be honest, I am noticing the difference already!

I wasn't supplementing my B12 previously - well just taking a lousy multi vitamin which wasn't doing anything!


Sorry to confuse KK - I assumed you were having to treat yourself because GP considered 433 was normal or high, as they often do in the UK. So it's good that you have an enlightened GP, who has accepted it is low, but are you being treated urgently with injections, as you also have clear neurological symptoms?

Extract from the book, 'Could it be B12?' By Sally Pacholok:

"deficiencies begin to appear in the cerebral spinal fluid below 550 pg/ml." "For brain and nervous system health and prevention of disease in older adults, serum B12 levels should be maintained near or above 1000 pg/ml."

Glad D3 is making a difference:) - Good to combine high doses with Vit. K2 to ensure it goes to the bones and not arteries.


It is not the best B12 in the product you are taking.Suggest Google" Dr Chandy B12 for interesting items.


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