Pernicious Anaemia Society
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Questions about Self-Injecting - feeling unwell

I have a few questions about self-injecting and really hoping you can help. Trying to find this out as feeling pretty unwell.

1) I heard to use to buy my injections. However there seem to be a few injectable B12 on this website. How do I know which one to buy?

2) How often do I inject?

3) Where about in the body do I inject?

4) Is it possible to over-dose - for example not having long enough between injections?

Thanks so much for your help!

5 Replies

First i would suggest you do go back to your gp and try to get them to address the symptoms that you have. There are various tests that can be carried out and they do need to be done before you inject or take any additional b12 onboard.

Lots use versandapo to get b12 and buy hydroxo

Syringes etc can be obtained from amazon

Utube has many vids of how to self inject

Most people use the thigh unless they can get someone to do it in the arm for them

Theoretically you cant overdose as any excess is secreted in your urine, but once you have supplemented with a high dose your b12 reading will more than likely be high or over the cutoff peramiter from the lab.

Other vitamins and minerals can all play a part in making b12 work as well. Ferratin, folate, pottassium, b6 and 9 and vit d. So it isnt just a matter of injecting b12.


I've been to the doctor lots of times. They don't listen to me! I might try going back again however its a 10-14 day wait to see a doctor and then when/if they book me into the nurse for an injection its another one month's wait. So I could be waiting around 5-6 weeks to get an injection meanwhile I'm off sick from work because of this and unless I started feeling better (within the next 2 weeks I think my job could be in jeopardy as they really aren't happy with me being off). So this is why i'm looking into self injections or at least until I can see a doctor. I'm fine with injecting as I've done it before for a different illness I had.

Thanks for telling me about versandapo - how would I know exactly which B12 injection to buy though? There seems to be lots on that website.


1 like

a) different people respond to different forms of B12. Some find methyl is best for them and others find hydroxo or even cyano better for them. Adenosyl if its available (haven't looked at the link) is likely to be problematic as it is very sensitive to heat and light so may not travel well. Hydroxo and cyano are less sensitive to heat and light than methyl. All you can really do is pick one and try and see if it works for you - if it doesn't, try another form.

If the problem is different strengths then go for a strength that gives you 1ml in a phial would be the most common.

Also possible that some contain folate as well - easy enough to supplement that orally so personally I would select that option.

b)+c) there are two ways to inject - subcutaneously - using an insulin needle - which can be done into thigh or stomach - or intramuscular which needs longer needles. Personally I stick with sub-Q - may be slightly less effective but it's a lot easier - intramuscular you probably need to get someone to show you to make sure that you are doing it right. Intramuscular needs to be done either into the muscles at the top of your arm or into the muscles in your thigh - unless you are a contortionist that probably means you need to do it into the thigh if you are doing it yourself

d) you can't overdose on B12 though some people do have some adverse reactions - some find that methyl makes them feel unwell - and if you are starting out on injecting then there is a chance that you may feel worse before you feel better - acne is another possibility.

If you have anaemia then you need to be careful of your potassium levels as this can be depleted in the early stages of B12 supplementation. You also need to make sure that your folate levels are adequate as without adequate folate your body won't be able to process and use B12.

Also, a very very few people can have an allergic reaction and experience anaphalactic shock - if you have had injections already that won't be an issue but if you haven't then it would probably be best to arrange for someone to be there the first time. It is very very very unlikely but you need to be aware of all the risks so you can take proper precautions.


I rotate Hydroxy, methyl and adeno injections. I've not had any problems with the adeno and found it very good for energy levels.


For more information you could look up my profile and see my post," My Experiences".

Good luck.


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