Thyroid UK
82,945 members97,982 posts

Advice on frequency of injections of Vit b12 methylcobalamin

Dear all

I have ordered vit b12 injections as this appears to be the most sure method of optimising the levels.

I have chosen methylcobalamin 20mg

My b12 test result this week was :

224 (range - 180 -900)

Can anyone please advise on the frequency I should be injecting initially please

Thank you in advance

Lu xx

17 Replies

Hi Lulu_65,

You can post this on the PAS forum within HU and the members there can also comment.

J 👍


This is an excellent site: Well done on your choice of methylcobalamin, it is what is recommended by b12d.

I believe there you start with a loading dose for two weeks (if I remember correctly it was every other day for two weeks) and then I went on to inject once a month.

Have a look here for the loading dose protocol:


Hi puncturedbicycle

Very useful info thank you.

I should have the b12 and syringes by Monday. Have ordered the saline from a company in Germany but don't know how long that will take to arrive. I just can't wait to get started

Lu x


Hi Lu.

May I ask what the saline is for? Is there mixing involved or something? (Just being nosy really. :-) )



Yes, the saline needs to be added to the powder and mixed. Once mixed it lasts for the duration of its shelf life as long as its stored in a dark place. Basically 1 ml of solution will contain 2mg of b12. My poor brain is not able to assimilate this to how much I should be injecting myself with

I couldn't find any ready mixed

Lu x


BCSH guidelines in UK for treating a B12 deficiency are 3x week for 2 weeks followed by 3 monthly with hydroxocobalamin. If you have neurological symptoms - such as tingling in the hands and feet then the recommendation is 3x per week until symptoms stop improving followed by maintenance ever 2 months.

There doesn't really seem to be any scientific evidence for the frequency of maintenance shots recommended above. In other countries where hydroxocobalamin is used mantainence frequency is monthly. However, you really need to go by your symptoms if you have a B12 deficiency.

Ideally you should try to get a medical diagnosis before you decide to self treat but ...

Methyl is good for some people but doesn't work for everyone


Thank you Gambit62

When you say I shpuld get a medical diagnosis are you referring to pa?

I had vitb12 checked this week and its just within range and my doctor signed it off as normal (haven't spoke to a doctor because I can't see the point. Every time I speak to them I come away feeling stupid). I have many symptoms of a b12 deficit and decided not to give myself the aggravation of asking the doctor to investigate something they think is normal.

Lu x


I wasn't actually talking about PA but about getting the existence of an absorption problem recognised - though know that that can be nigh-on impossible when GPs are determined to go by test results despite there being a load of evidence out there and mention in guidelines that the results aren't the whole picture and symptoms need to be evaluated as well. With thyroid problems even getting symptoms recognised is going to be difficult because of the huge overlap with a pre-recognised condition - so can fully understand not wanting to go down that route.

PA is just one possible absorption problem - whatever the problem the treatment is the same so tying the absorption problem down - although per guidelines - isn't something that I'd consider necessary (or anything but a potential journey into madness). The reason for trying to get a recognised diagnosis of an absorption problem would be to ensure correct treatment in the future but given that that might be at the risk of significant damage to your health (and sanity), totally understand if you aren't prepared to travel down that path.


Ahh, sweet sweet sanity. Like Lulu_65 I just decided to do it myself. I'd been taking high oral doses of b12 w no resolution of any symptoms whatsoever - basically expensive pee - and I was offered a b12 jab by a (private) doc I used to see. I thought, Hmm, if she's okay w it why don't I give it a go myself? My test results showed levels high after supplementing, then dropping like a stone immediately after so I figured there might be some absorption issue.

Even w compelling results a lot of folk are having trouble getting treatment. Are you on the PAS board? There are people (w PA dx) who aren't being treated, or jabs are limited to three or four a year.

This is such a problem, and w all the ruckus about dementia you'd think it would be such an easy way to improve things (maybe not a full fix, but we know how many older people are severely deficient and how the symptoms can overlap).

It seems to me that gps are too involved on this level and all they're doing is clagging up the works and getting paid, where it would be so easy to have a nurse show people how to do their own injections and send them home w their stuff. Or a weekly b12 clinic - ? I mean apologies to any gp who might find that upsetting but I can't think of any compelling reason why they need to keep the reins this tight on b12 knowing what we know about neuro damage.


Yes, member of the PAS forum - don't have thyroid problems - do have B12 problems - and mine were actually made worse by injections - having been told I was B12 deficient in hospital after a fall that broke my ankle - lots of c**p about osteoporosis but absolutely no information on B12 and whether I had balance problems/neurological issues as a result of the deficiency. It was a teaching hospital and the only thing I came away with from the quiz on B12 was irregular bowel movements ... so not surprised that GPs don't really know much about it ... possible that one of the students may have mentioned osteoarthritis but ...

My mother has similar problems having been identified as B12 deficient and given loading shots - so now have to keep levels astronomic all the time because of a reaction that just stops any B12 getting through to cells unless the levels are astronomic. Mum has significant cognitive problems but everything gets put down to diabetes ...

Totally agree that the amount of penny pinching that goes on with B12 treatment is ridiculously short-sighted. The 'fashion' for IM injection really doesn't help as there's plenty of evidence that subQ is as effective ... and that would make an epi-pen a possibility as per diabetics treating themselves for insulin. There really does need to be a lot more done on educating GPs and looking into getting treatment that is actually appropriate to individuals rather than applying text book standards.


Exactly. Epi-pen is a brilliant idea. What a shame your injections didn't help, esp if you share your mum's problem. How do you address it?

Sc is working for me. That b12d site above says it's just as good if you're doing regular injections. Maybe it isn't as good if you're only getting three a year from your gp.

All kinds of symptoms I didn't think could be related to b12 (as I had been on massive oral doses and nothing changed) just eventually disappeared w sc injections: no more tinnitus, no more sore balls of feet, numbness in toes which I have had, omg, since I was in my 20s maybe?, that has improved too.

Also, and sorry for tmi, but I would recommend for anyone experiencing lack of sexual sensation and/or sexual anhedonia. I can confirm if there are neuro issues b12 could sort it out very unexpectedly.


The only solution to my problem is to keep levels really high - which I tend to do with nasal spray rather than injections.


You need to have five in the first two weeks at intervals of about 3 days then one approximately every twelve weeks although you may need it slightly sooner. who is injecting you?

1 like

Thank you

I am going to inject myself. I used to be a nurse so it isn't a problem for me

Lu x


NICE guidelines are injections *alternate days* until no further improvement (or for two weeks depending on whether there is neurological involvement).

I do subcutaneous because it's easier for me, but the b12d site says either are fine. Just fyi in case you don't fancy im. (I'm ok w sc but a bit squeamish about the idea of im.)


Hi puncturedbicycle im definitely going for subcutaneous. I had a horrible experience of an Im injection after the birth of my first child and have never had one since!


1 like

Eek, yes, bleurgh. Reminds me of tetanus jabs. The nurse would virtually have to do a run up to get it in *shudder*. And then you couldn't raise your arm for days. xx


You may also like...