Pernicious Anaemia Society

Loading doses

I'm looking for some info on 'loading doses'. I am type 1 diabetic since 1982 and was diagnosed with PA in May 2013 at which time I was experiencing confusion, poor concentration, poor memory, paranoia etc. I went to the docs who took blood and did test for depression etc. Came back to be told 'not depressed, bloods ok but Vitamin B12 is at 32 which is a bit low.' He gave me a prescription for Vit B12 and said ' you'll be on these every 3 months for life just see the nurse and she'll give you it. ' Appointments for the nurse was two weeks away but that was, according to them, ok. Came home researched, kicked up and got injection after ten days then fought for another a month later then it was 'see you in three' months. My readings have been around 200 at 2 weeks before tests.

My questions are. 1) Should I have been given loading doses. 2) why are loading doses given and 3) what would the optimum reading be.

Grateful for any info or links.

10 Replies

Please don't tell me I'm reading '32.' Please tell me you have made a typing error.


1) Yes, you should have been given loading doses. It is standard practice. 2) Loading doses are given to raise serum b12 levels to a stage so they cannot fall back into the deficient range prior to your next injection. 3) There really is no maximum once your have been identified as deficient. Keeping the level as high as possible is the aim, even if this is over the 'normal' high end of the range.

I'm going to have to go and simmer somewhere quietly before I say anything else.

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Thanks again poppet11 for your reply. Yes my reading was 32. I have been a member of this community since sept 5 and the information I have gleaned is phenomenal. I am, if my reading is again low, going to ask for more frequent doses and so want to have as much data as possible to counteract any argument. I cannot understand the reluctance of GP s to increase the frequency if it's needed.


The very bottom line is that they don't understand b12 deficiency.

It's the most ridiculous thing and sometimes I get lost for words.

How something as important as this can get overlooked by contemporary clinicians leaves me completely gobsmacked.

We really have got into a situation where many, many patients now know a lot more about b12 deficiency than the professionals who they turn to for help.

That is not acceptable.

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Yes after six weeks on this blog that's the impression I get and I see my own GP in many of the posts on here!

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I can't believe that your GP described '32' as 'a little low' ... it's actually very, very low.

Lots of people can be symptomatic of B12d at levels well into the 'normal' range so 200 isn't really that high - particularly given that you have been receiving shots.

There are no optimal readings for B12. Unlike insulin, too much isn't as bad as too little. I hate to think what my levels are likely to be now given how much I self supplement but I'd expect them to be well above the normal range.

Also, unlike diabetes, there isn't a really good test that determines whether you are deficient or not. The Serum test looks at all the different forms of B12 and doesn't focus on the metabolised forms that your body actually uses for all the vital processes that B12 is involved in. There is another test - active B12 but even that isn't a precise indicator. There are some further test that can be used in conjunction with B12 as indicators of deficiency (looking at waste products that build up if B12 isn't present - but B9 (folate) will also have the same effect, so important to know what your folate levels are as well.

Its possible that you may have other symptoms of B12 deficiency that aren't being recognised as such because they have such a lot of overlap with diabetes.

Type 1 diabetes itself is also a flag that you may be prone to B12 deficiency.

Really would suggest that you try getting hold of a copy of Could it be B12? read it and then think about passing it on to your GP with some relevant sections marked.


I just think it indicates that both the GP and nurse think b12 deficiency only develops into an anaemia and that's when it gets serious. Patient doesn't have anaemia or is not dying of anaemia then it's no problem.

If you think about it in those terms you can see exactly why they are so casual about it.


NICE recommends that B12 deficiency with neurological symptoms be given every two months and you are probably already aware that symptoms connected with B12 deficiency can be irreversible if not treated urgently.

A close relative had similar symptoms and after much pleading we emailed this to the surgery but had no response and they appear to be sticking to their three monthly injections plan. In between, we have found the 500mcg B12 methylcobalamin sub-lingual spray from Pure most effective. (Available from Amazon UK).

Very best wishes Weewul.


Have you tried supplementing you injections with sublinguals or nose spray? Before my MD increased the frequency of my injections, I found that I felt much better when I supplemented the shots with sublinguals every other day. Good luck and I hope you feel better soon!


Hi again, thanks Poppet for the helpful info. Likewise Gambit I bought the said book and started on it yesterday, Polaris and NJmummy thanks for the link and advice re sublinguals I wasnt sure if they were for PA sufferers or for B12 deficiency. Lots to think about!


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