Log in
Pernicious Anaemia Society
16,691 members11,555 posts

New to self-injecting - subcut vs IM advice, please?

Hello everyone,

I'm new on here.

As appears to be many people's experience, my GP is withdrawing my B12 injections, despite ongoing neurological symptoms.

I'm planning to start self-injecting, and would prefer to inject subcutaneously, but don't want to risk a worsening of my symptoms.

I'd be interested to hear of others' expriences/views on subcutaneous vs intramuscular?


8 Replies

Many people here use sub-cutaneous injections with no problem.

The only difference between the two routes would be the rate at which the B12 enters the bloodstream. But nobody knows which would be faster than t'other. It's very unlikely that the difference would be enough to be significant.


Hi Jennylind,

Are you in UK?

I'm asking because patterns of B12 treatment vary from country to country.

Do you have a diagnosis of PA (Pernicious Anaemia)?

If yes, I'd suggest joining PAS (Pernicious Anaemia Society). PAS is based in Wales, UK but has members from around the world. Some info on website is aimed at UK.

If no, can you remember why you started receiving B12 injections?



PAS tel no +44 (0)1656 769 717

PA treatment is for life. There is a leaflet PAS members can print off for their GPs called "Treatment is for Life"


BNF (British National Formulary) Chapter 9 Section 1.2 has info on UK b12 treatment, think it mentions treatment for life. BNF is a slim book that all UK Gps have access to. Possible to get own copy from good bookshop or internet retailer.

There are stories on Martyn Hooper's blog about how PAS has helped PAS members whose injections have been stopped. Think it's easier for them to help people with a confirmed diagnosis of PA.




Flowchart from BSH Cobalamin and Folate Guidelines (UK document)


Flowchart outlines when PA and Antibody Negative PA can be diagnosed. Sadly some UK GPs may be unaware of the BSH document.

If in UK, I'd suggest reading whole BSH Cobalamin and Folate Guidelines


Unhappy with treatment (UK info)?

Link about writing to GP about B12 deficiency


CAB (Citizens Advice Bureau)


HDA patient care trust


UK charity that offers free second opinions on medical diagnoses and treatment.

There are others on the forum who have had injections stopped. Link to thread of someone whose injections were stopped. May be useful links on thread.


"my GP is withdrawing my B12 injections"

Why is GP withdrawing your B12 injections?

Some people on forum have pointed out the potential consequences of undertreatment of B12 deficiency, including spinal damage, to their GPs.



My understanding of the BSH Cobalamin and Folate Guidelines is that all causes of B12 deficiency which result in neurological symptoms need the neurological treatment regime.

I am not medically trained just someone who has struggled to get a diagnosis.

1 like

I am in the UK.

I don't have a diagnosis of PA, just of B12-deficiency based on a low serum B12 result only. I have years of 'unexplained' symptoms, which now seem to me to have an explanation.

My GP was initially very open to longer-term injections on alternate days (once shown the NICE guidance, which she was not aware of), however, she has now been directed by a haemotologist to cease these as my serum is within 'normal range'. I will continue to argue my case, and feel confident and competent to do so, but I am not sure that it will be effective.

In the meantime, though, I don't want a reversal of the amazing results the injections have achieved - I am enjoying feeling alert and energetic for the first time in years too much!

1 like

I had tests that also showed high auto immune antibodies and mild stomach atrophy. Maybe you should ask for tests for these. The first one the lab suggested was positive for PA, but the gp thought it was my thyroid condition. when i was tested again it was 20 and i had angina through it. get it checked. The angina reversed.


Have you had your folate level checked?

As to the injections - I've had over 600 B12 shots during the past 45 years and they have all been administered by nurses into the upper arm muscle.

I wish you well

1 like

I was pretty sure that they have to be in a muscle, but although I've had this for years and years, I've only just recently been learning.

Sorry for wasting your time. :)


US used to have a micro site which said it could be done either Sub Q or IM

Think that doing it IM and saying it has to be IM in UK is actually just because it has always been done that way. Sort of the same as the whole thing about 3 weekly being perfectly adequate as a maintenance routine.

As fbirder says there is no evidence to show that IM is actually better from a patient perspective than subQ, or even that it actually is more effective - most studies have concentrated on measuring the effects of the two methods on levels of B12 in blood and don't really show much of a difference there.


Thanks for all the responses.

How have you all determined how frequently you need to inject? I don't really want to keep allowing my symptoms to return and only then administering another injection, but is there any other way in the beginning?


You may also like...