B12 loading doses query : Hi, I’m... - Pernicious Anaemi...

Pernicious Anaemia Society

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B12 loading doses query


Hi, I’m getting the rest of my loading doses next week & the week after. Had an injection this week. The nurse who does b12 is only in Tuesday and Wednesdays, is that ok to have the b12 injections one day after the other for two days for two weeks? She uses a small needle, I’d prefer her to do them. Any advice would be helpful so I can try and move the appointments or not, thanks

26 Replies

Although it's recommended that they are given as six injections over two weeks there should be no problem having six injections over three weeks if that is what you would prefer.


I'm assuming you're in UK and your GP is going to give you 6 loading injections in total.

1) UK recommended treatment pattern for B12 deficiency without neuro symptoms is ...

6 B12 loading jabs over 2 weeks followed by a jab every 2 or 3 months

2) UK recommended treatment pattern for B12 deficiency WITH neuro symptoms is ...

A B12 loading jab every other day for as long as symptoms continue to get better then a jab every 2 months

How often will you have B12 injections after loading jabs are finished?

Do you have any neuro symptoms eg

tingling, numbness, pins and needles, burning sensations, insect crawling sensation, tinnitus, muscle twitches, muscle fasciculations, flickering eyelids, restless legs syndrome RLS, vertigo, migraine, clumsiness, dropping things, bumping into things, strange gait (unusual way of walking), word finding problems, balance issues, brainfog, proprioception problems (problems with awareness of body in space) etc?

Does your GP have a list of all your symptoms, especially any neurological ones?

Symptoms of B12 Deficiency




In relation to B12 deficiency, GPs often look for signs of peripheral neuropathy PN especially signs of sensory neuropathy so worth mentioning signs of PN.

Link about PN


Vital to get recommended level of treatment or there is a risk of further deterioration including neurological damage.

Neurological Consequences of B12 Deficiency

PAS news item


UK B12 documents

BSH Cobalamin and Folate Guidelines




BNF guidance on treating b12 deficiency changed recently.


Link about writing a letter to GP if under treated for B12 deficiency with neuro symptoms


A B12 book I found useful

"What You Need to Know About Pernicious Anaemia and B12 Deficiency" by Martyn Hooper

Martyn Hooper is the chair of PAS (Pernicious Anaemia Society). Book does not show updated BNF info.

B12 websites

PAS (Pernicious Anaemia Society)

Based in Wales, UK.


PAS tel no 01656 769717 answerphone

B12 Deficiency Info website


I wrote a very detailed reply on another forum thread with links to other B12 books, B12 websites, UK B12 documents/articles and other B12 info.


I am not medically trained.

clivealiveForum Support

I have, on occasion when a nurse was unavailable had my GP give me my B12 injection. He looked slightly "taken aback" but I told him it would be "good practice" :)

I wish you well.

Nackapan in reply to clivealive

Yes I've also had a Gp do it and a practicional nurse . Rather than the practice nurse

I have neurological symptoms but my GP flat out refused to give B12 shots more than every two months.

Even when I showed them the nice guidance.

Has anyone experienced this ?

wedgewood in reply to Mammaelf

Yes I have . I had diagnosed P.A. ( had to go to private GP to get it ) My feet were numb, but my GP would only give me an injection every 3 months . My numb feet were“ idiopathic” and nothing to do with P.A. . Another GP in the practice backed this up . So I then had to resort to self-injection . Luckily in good enough time to get rid of the numbness , but I’m left with a burning sensation in my feet . Start self injecting if you get nowhere with your doctor. You don’t want to be left with irreversible symptoms. I’ll send you the info. if you are interested . Best wishes .

Mammaelf in reply to wedgewood

Yes please x

There are lots of us who self inject every day so it's perfectly safe to do so.

One loading protocol (I think the Dutch one and based on the extensive B12 research that the Dutch have done) says one a week for six weeks and if I could turn back time I would try this as it less of a shock to the system.

So it's difficult to call, especially as each of us are different.

This can be a serious and difficult condition to manage so please do what your body needs if you can, even if it might mean getting a jab from someone you like less than the nurse.

Would it be too much of a shock to the system having two injections one day and the one the next? For two weeks? (4 injections) if it’s fine to do that then I think I will just stick with that to save time. I’m so lucky to even get the loading doses it’s been a real battle to get here!

It's impossible to say as we are all so different.

I suspect that while your system will probably cope OK it could mean that you don't need the amount of B12 supplied by injections on consecutive days and therefore your body will excrete more, meaning that you will lose some of the benefit of having your second jab each week.

I have a concern (that I don't have scientific evidence for) that there is a slim possibility that frequent jabs at the start of treatment may trigger a reaction that means you will need more frequent jabs in the future. However this is only an observation that doesn't apply to all people.

The bottom line is once you have had a jab and not had any allergic reaction to it you know you will be safe going forward and if necessary you can buy your own jabs kit and self inject.

Each self injection, complete with ampoule, needles and syringe will cost you about £1 so they are not impossibly expensive.

Thanks for your advice. I’m maybe thinking maybe one a week is better for me then perhaps? Instead of two on the two consecutive days. I had one injection this week yesterday but it’s the only slot I could get this week hence it being a sole injection I had no reaction just slight stomach cramps in the middle of the night.

I could ask to have the remaining loading doses one per week, would this give the same effect as the loading doses in the two week period? Thanks for your help ☺️

I think thats happened to me I appear to need much more now. . I would also in hindsight had one a week for 6 weeks. As my serum b12 106 at start my body felt overwhelmed but who knows??

I do tend ti 'overreact ' o anything g I take or sensitive or receptive?

2 a week sounds okay

Just important to get the treatment to halt any damage .

CherylclaireForum Support in reply to deniseinmilden

Yes !

Always had a nagging feeling that after years of unnoticed gradual deterioration, the injections were a shock to a starved system unused to having a flood of B12 and unsure what to do with it. Think protective barriers went up (?)

Of course retrospective, simplistic and no medical evidence.

Often felt that I would rather have 1/2 injection every day than 1 every other day, too, but not possible.

Now doing okay on 2 a week - but not so great when 1 a week. Pushed my luck.

It's still progress though.

Perhaps try one a week at first, mistygrey - and discuss it with nurse ?

We are all different and react differently, so hard to tell.

Thank you for your ideas on it too. It is only anecdotal at this stage but everything has to start with an idea!

Nackapan in reply to mistygrey

I think you will be okay.

If the first week you felt you coukdnt cope. Look again at options

Just so Important to get tour treatment

mistygrey in reply to Nackapan

Would my body dump the overload of b12 if I get two injections in two days or doesn’t it work like that? I’m just worried I get two next week and two the week after and my body dumps a large amount of it as it’s a lot at once. I had one injection this week but not feeling much better after it yet

If I could have one each week then I would in preference and personally think this is a better option than the standard protocol.

It may take a little longer to get the full effect but each injection should supply you with plenty of B12 and in the long term it could be much better for you.

You won't lose anything by trying it - it is the lowest risk option - and if you find in time you need more then you can look at the other possibilities then.

Thank you. I will speak to the surgery today, I thought the initial loading doses needed to be done closely together to get maximum effect but if that’s not the case one weekly would be fine I’d imagine?

Exactly! To get maximum IMMEDIATE effect then they need to be done together but with doing them weekly you should get the same level of effect in time, it will just take longer.

My nutrition knowledge is based on animals and in animals we try to make gradual changes, rather than abrupt ones, so the body gets a chance to cope with the change rather than it setting up an adverse reaction. People are "human" animals.

While B12 is safe in large doses and if you supply more than is necessary it is usually just wasted, there is an additional condition called "functional B12 deficiency" whereby the body stops using the B12 it has properly and so large amounts are then always needed. I suspect this could be an autoimmune response to going from being severely depleted to suddenly having an abundance, as happens with 6 jabs in 2 weeks. It only happens in a few people but if you don't need to take the risk, why do so!

I wonder why most people insist on having the two week loading at 3 day intervals each week?

My nurse is fine to do them

Two days next to each other next week as that’s the only days she’s in and to be honest she uses the smallest needle so I much prefer her. But if I got one a week I’m sure it wouldn’t be a big issue as long as I get the full loading then go to my 8 weekly injection which has been agreed by Gp?

CherylclaireForum Support

Don't think most people, when told they are B12 deficient and to book up a course of injections with the nurse, know anything about B12 or the injections or that they then will be every 2-3 months for life, generally speaking.

( - Or until a new GP decides to check your B12 levels 5 years down the line and stops your injections until you are deficient again ! )

Stunned more than insistent, I think.

I’ve managed to sort an injection a week instead of the two per two days next week, hopefully this will work for me. I’ve had one this week and another 1 per week for 5 weeks equalling the 6 then an 8 weekly injection. Hopefully this will be ok if anybody thinks it won’t let me know? ☺️

CherylclaireForum Support

It sounds like a sensible plan, and will hopefully work well for you. Let us know how you are doing, won't you ?

Best of luck

One possible problem which I alluded to in my first post is if you have neurological symptoms and the GP puts you onto a jab every 2 or 3 months after you have finished your 6 loading injections.

6 loading jabs may not be enough to start repairing neurological damage in someone with neuro symptoms.

Everybody is different though and what suits one person may not suit another.

In UK, patients with neurological symptoms are supposed to have more loading injections over a longer period than those patients without neuro symptoms. See BNF and BSH links in my other post.

GP can find the info for UK B12 treatment in their copy of BNF book Chapter 9 Section 1.2

(they'll have a copy of BNF book on desk or bookshelf).

If you're in UK and have decided with GP to have B12 loading jabs once per week instead of every other day and you have neuro symptoms, I would expect the GP to continue giving once a week jabs for a few months.

Vital to get adequate treatment or there is a risk of further deterioration.

Neurological Consequences of B12 Deficiency

PAS news item


Symptoms Diary

May be worth keeping a daily diary that tracks changes in symptoms over time and when treatment is received. It can be useful evidence of improvement or deterioration in symptoms.

If you have time, have a look at the link at the bottom of my other post which has a lot of detailed info.

I am not medically trained.

My B12 came 😉. Ordered it from versandapo.de/vitamin-b12-d...

Better to space them out I think, but the dr should advise you about that. x

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