I've been SI 1500ug twice weekly since mid December as a bit of an experiment to see if it would help my symptoms, many which are neuro. Not officially diagnosed as B12 deficient as my blood tests before were all fine but I was heavily supplementing so not really possible to say they were accurate.
I recently did a private blood test for another reason which happened to include total B12. I know it goes up with injecting but I wasn't expecting to see >4000. I see others talking about more than 2000 but not more than 4000. Is this ridiculously high and I need to step back a bit or do I just continue with my current regime?
Active B12 on another test a month ago was >188 so over the top of the range. I guess this shows it's getting into the blood.
I haven't really noticed any improvements but then maybe I have other things going on at the same time, or B12 deficiency may not be the problem at all and I may be barking up the wrong tree.
Just wondering if such a high result indicates I'm over doing it?
Written by
Bertiepuss
To view profiles and participate in discussions please or .
I think that the only reason that you see people saying that their results are more than 2000 is because that's the upper limit of the particular lab that tests their blood. Mine always comes out at more than 1500, because that's the local lab's high limit. Obviously some test to a higher range. Chances are a lot of people who inject regularly are a lot higher than 2000, they just don't know it.
It would be interesting to know if you have raised MMA, which could indicate a functional deficiency despite normal serum results. The other possibility is that the symptoms really aren't anything to do with B12 and something else is going on. The third possibility (I dont know your history so this may not apply) is that symptoms were present for too long (many years) without treatment, although in general SOME improvement would be expected in most cases.
The B12 serum number has no clinical significance now since you started treatment so I wouldnt read anything into it one way or another.
Thanks Technoid I will ignore that result and consider unmeaningful.
Do you think it it worth doing an MMA in that case, to check to see if it's raised? If it wasn't raised, would this prove there was no functional deficiency and I could be confident the injected B12 was getting into the cells?
Yes, some symptoms have been present for many years, others are newer in the last 18 months. Also I have been dealing with severe iron deficiency which I am also addressing at the same time. Both this and B12 have overlapping symptoms as you know so hard to say what belongs to what. Also thyroid problems which the kind people on the Thyroid UK forum pointed out may be a problem for me when looking at my results.
The whole B12 and PA testing thing I find so difficult to understand. Before I came to the forum I was on a FB group and was advised that an optimal result in any of the B12 tests, including MMA would not prove I didn't have a deficiency because I had been supplementing B12 sublingually for a long time and that the only 'proof' would be trying injections to see if they helped or not. As a vegan I was supplementing for years, if I hadn't then of course I would have become deficient.
I sort have wished I had now done an MMA before starting the injections but I was advised it was a waste of money and wouldn't tell me anything conclusive. Too late now!
I don't know how best to proceed, with the B12 - keep going and see how I feel in another 3 months time?
There is no gold standard test to rule out deficiency or rule out PA but that doesn't mean the tests are useless. if MMA is tested and found to be raised, and other possibilities for a raised MMA are excluded, then it would look increasingly like there was still a B12-related issue. However, my MMA was NOT raised when tested just before I started treatment. So it's not perfect for ruling out deficiency but it IS very useful for ruling one in, similarly to the IFAB test for PA.
My personal experience was that even 3x 250mcg oral tablets had a dramatic effect some 10 hours after taking the first tablet, when intrinsic factor starting to ferry the B12 into my system. There was no mistaking either the effect of my first injection, which improved some things but also dramatically increased nerve pain and many other horrible symptoms and exhausted my leg muscles which I now suspect might have been ATP depletion. But my experience was far from universal as I did not have absorption issues or PA.
If you do not have raised MMA and symptoms have not been affected in any way by the B12 injections, I would be increasingly suspicious that it may not be a B12 issue or that there is a second complicating issue (severely low iron status for example).
Hello! 👋 🌱🥦 Thank you, you confirmed my thoughts on testing not being able to rule it out if negative.
Hmm, well I was already taking 1000mcg B12 sublingual before starting SI and was not feeling well. 2.5 months of SI and I don't feel any difference so maybe B12 deficiency is not my problem. My low ferritin is coming up, although still not at optimal levels so need to continue with this.
This is the problem - I could spend lots of money on more private testing (GP will not offer me anything as my total B12 was initially at the upper end of the range) and if all found negative it will not rule out a deficiency or PA. If anything was positive then SI would be proven to be the right path. But, it's cheaper to not do the tests and just inject and see what happens.
I suppose I just continue whilst exploring other avenues. It seems that continuing with injecting will not do me harm even if it does not bring positive results. How very frustrating!
I think you’d be wise not to put all faith in B12 deficiency being the root of the problem, or the only problem, and injections are the only solution.
As I have posted separately today, I’m exploring whether diabetes or pre-diabetes could be the cause of my most common symptoms as there is a lot of correlation. If so, the treatment would be different and not necessarily B12 injection based.
I think it easy to be sucked into thinking that it’s all B12 related because of the wide ranging symptoms.
I’m keeping a very open mind and exploring all the options. But continuing with B12 injections just in case!
Yes indeed. I am chronically iron deficient, which I am addressing, and I'm also exploring other avenues. Seems like it's the same for you with working out where the problem lies. It's so hard to pick apart what symptom relates to what problem and therefore which course of action to take. And, when the GP gaslights you, then the only option is to take matters into your own hands. I just wish there was more help from medics but instead I have to rely on the internet and other peoples lived experiences. Thank goodness for the kind people on here that try to help us!
I don't have the original or a link, but look for "Treatment with high dose vitamin B12 been shown to be safe for more than 50 years". It will explain everything.
My B12 levels are also >4,000 and my symptoms are also myelin sheath / nerves . Most doctors will tell you to cut down the injections, but I can't get a decent night's sleep unless I inject 2 to 3 time a week, failing which the anxiety seems to suddenly creep up 'from no-where'. Not sure if that helps.
Bertiepuss Have you checked your folate levels ? B12 & folate are dependent on each other, hence if one is low the other cannot convert properly. What type of cobalamin are you using. I only ask because methylcobalamin requires a much greater amount to be effective.
Yes, I've been keeping a check on folate levels every 2 months and in fact ended up over range from only supplementing 400mcg a day. I have a diet rich in folate so that probably explains why I don't really need more. I'm using hydroxocobalamin.
Bertiepuss - If B12 deficiency is your issue and is caused by diet (lack of B12 products in diet) oral supplements are ok "only" if "no" neurological symptoms. With neurological symptoms then injections 1000 μg i.m. of hydroxocobalaminon alternate days until there is no further improvement (see nice guidelines in UK). All those years of taking sublingual's would increase your levels but they cannot get your level high enough to permanently "heal" those symptoms or stop new ones from occurring. You are in the early days and perhaps you will need additional inj. Attached link from the British Journal of Hematology addressing frequency of injections. onlinelibrary.wiley.com/doi...
I'm not convinced at all by the claims that much higher doses of methylcobalamin are needed to be similarly as effective as cyanocobalamin. The RDA for B12 was formed based on B12 consumption from foods which are typically a combination of adenosylcobalamin and methylcobalamin, possibly some hydroxocobalamin. It doesn't make any sense that if you supplemented these forms, then gigantic amounts would be needed in comparison to cyanocobalamin which is found only in small amounts in some, typically fortified foods.
I have reviewed the papers regarding the claimed need for dosage differences and I find the evidence for a massively increased requirement for methylcobalamin to be unconvincing. Some of this evidence is based on the amounts of methylcobalamin given to alleviate B12 deficiency or to treat individuals who had a gastrectomy, for which 1000mcg+ (of any B12 form) is a common treatment dosage but this says nothing about the amount needed for maintenance of good B12 levels in a healthy person with working intrinsic factor.
Interesting. I've always wondered what the amount of B12 is in a typical omnivore's diet who doesn't supplement. Is it the RDA of 2.4mcg or is it more? And if so, those that have no problem with intrinsic factor, does that mean they get enough to show up as well within the reference range in serum?
A few years ago I was supplementing 50mcg B12 as methyl and my total serum levels were mid 400's. Once I started supplementing 1000mcg (mix of adeno and methyl) they went up to mid 700's - so 20x the amount did not result in 20 x the level in the blood. Now, if I'd not been supplementing at all and got my RDA of only 2.4mcg from my fortified soya yoghurt for instance, I wonder if levels would have still been in the 3/400's or would they have been a lot lower? I will never know.
The average maximum is 30mcg but most get a lot less than that. 6mcg (for example with 2mcg split over 3 meals) would be quite sufficient to maintain excellent B12 status since you max out the IF uptake in each meal.
The biological requirement (after absorption) is around 1-2mcg. With PA, in the worst possible case of 100% B12 losses from bile (enterohepatic recirculation being broken), there would be an additional 5mcg per day requirement.
So an awful lot lower than the amounts usually seen in supplements. Have I understood correctly - as long as you are producing IF, and are eating/supplementing a minimum of 6mcg per day, you should be able to maintain excellent B12 status?
No IF means you can't absorb (serum levels will be low). Not meeting the minimum requirements through food/supplements means you develop a deficiency (serum levels will be low). In both these cases a deficiency will be obvious on tests and makes complete sense to me.
In my case my serum levels were good yet I was told (on FB) I could be deficient at cell level, therefore it was worth trying injections. Is this correct? I was told that supplementing can raise blood levels on tests yet you can still be deficient. I am totally confused and just don't know whether to continue with injecting or not. I would value your thoughts on this please.
Yes, with functioning intrinsic factor the RDA is actually only 2.4-2.8 mcg in total over the whole day, but an optimal intake is considered closer to 6mcg in total over the day, for which 2mcg at every meal would saturate intrinsic factor absorption completely. Intrinsic Factor is the natural B12 absorption mechanism, which does not function in PA due to an autoimmune attack against IF and the parietal cells that produce it.
The massive doses you see in supplements exist because if you only get B12 once a day or once a week you need to take a much higher dose, which gets absorbed by passive absorption "an accident of physiology" which absorbs only 1-3% of a dose. The larger doses also exist to be more helpful to correct B12 deficiency.
Yes, it is possible to have normal or high serum B12 and still be deficient at a cellular level, this is functional B12 deficiency. Transcobalamin deficiencies would cause this but there are other possibilities such as the presence of Macro-B12. I know for at least one forum member in whom functional deficiency was confirmed, MMA remained high, indicating that adenosylcobalamin was still not sufficient or not working as it normally should, for unexplained reasons.
Don't panic. The dynamic range of the test in question is the key thing. Any lab would be able to report results to infinite levels by performing serial dilutions of the sample and re-running the test. All this would do is simply increase the cost of performing the test with no clinical benefit. It's costing us all quite enough as it is! My lab performed serial dilutions when testing for serum ferritin, as that might well be relevant, but B12? Nah!
Thank you for explaining, so quite likely anyone self injecting would have extremely high levels, possibly way above 4000, it's just never measured and reported on. So, whether it is reported as >1500 or >4000 (where those values are the labs top of the range) essentially doesn't matter as the result may actually be >10,000 for all we know, just that the lab will never perform the serial dilutions necessary. Have I understood correctly?
Got it in one! Each time we do another dilution run, it uses another test out of the kit, and there's no real need for it. By the time we've done the test, you'll have peed out some of it anyway! There's no reason to repeat test anyone who is on injections, as it's always going to be in excess. Better testing some of the other folks who haven't been tested at all.
Content on HealthUnlocked does not replace the relationship between you and doctors or other healthcare professionals nor the advice you receive from them.
Never delay seeking advice or dialling emergency services because of something that you have read on HealthUnlocked.
B12 injections discontinued
Reaction to b12
Doctors refused any more B12 injections after 5 years 
B12 injections been stopped
Teenagers symptoms returning 4 weeks after B12 loading injections.
