Hello, I'm interested in finding out if anyone has similar symptoms or experiences to me as I'm trying to work out if b12 is the culprit of my issues or even a major factor. Any information would be useful as I've had 5 years of 'we don't know' from medical profession.
I'm 34 and in 2015 when I lived in Thailand, people started commenting I walked with a limp. I ignored it as I didn't really notice it and was still mountain biking, climbing, kayaking etc. In 2016 I started finding it harder to walk uphill and was very tired but I was an outdoor instructor, tiredness was part of the job plus I had an underactive thyroid. Long story short someone noticed I had muscle wasting in my right calf and I couldn't lift my big toe or stand on my toes. Referred to a neuro consultant and have had muscle biopsy - normal, genetics tests - normal, nerve conduction showed abnormalities. They've diagnosed me with Distal myopathy with no treatment just physio. I've had tests for tropical diseases which showed EBV and low immunity to hep b but not much else. Since then my grip in my left hand has got worse and my walking is definitely not what it used to be, partly because walking was my biggest passion (used to walk 23miles on a Saturday for fun!) and now it's a horrible reminder I struggle with a few miles and sometimes 5min is my max. Both legs are now weak and heavy and I get very tired.
I've been through various theories of the cause and I recently discovered this forum and am really curious if b12 could be related to it. I have quite a few of the symptoms on the list such as tinnitus, psoriasis, depression/anxiety, brain fog etc.
I've had active b12 and MMA tests done, active b12 - 146 pmol/L and MMA - 19.6ug/L which are apparently normal?
But I see a kinesiologist and using muscle testing has said I need a whopping 24 ×1000mcg b12 adenosylcobalamin tablets/day!!
Really interested if anyone has functional b12 deficiency despite normal blood tests? Or has similar patterns of neuropathy/myopathy?
Written by
gemini4378
To view profiles and participate in discussions please or .
I'm not a medical professional but I must say I am hugely sceptical about the claim that you need to be taking that amount of adenosyl B12One reason for being sceptical is that the process that transfers B12 from blood (post absorption in the stomach) into cells would actually strip the adenosyl component from the B12. The cell would actually recombine the adenosyl component with the B12 in the cell if it needed adenosyl B12 to run a particular process.
Another reason for being sceptical is the amount of individual variation in B12 requirements.
I think it is correct that adenosyl B12 is the one that would be used in the release of energy which would be a contributor to muscle strength but I just don't see how anyone could be that accurate about requirements just from testing the strength of muscles.
B12 deficiency tends to be symmetric because it operates at the cell level but a significant part of what you describe in terms of development appears to be asymmetric.
I did find this article on distal myopathy on a rare diseases website - which explains that it is genetic in origin and that there are several different forms.
Hello, that does help thank you. You say it's clear you have b12 deficiency, did you have blood tests that showed this? (you don't have to answer this if you don't want to). Thank you!
I supplemented before because of delays and was very late stage. Panic and anxiety kicking in. I was also naïve that it wouldn't make too much impact.
So my test was 650 but Ive been self treating with many many highs and lows.
Of course theres a small chance it isn't B12d but judging by the chaos in my mind and body in the last 3 months - and my daily self injection - it would seem bizarre that Ive improved and for it not to be b12.
Im torn between the myopathy being a result of daily alternating thigh injections or from the leg nerves healing up that caused me the chaos to start self treatment before my test.
Stuff of a David Lynch movie. Bizarre and confusing!
Myopathy is slightly better but still there in both legs. I feel Im walking on bones. Thigh muscles are distorted and calves are weak, not responsive. Theres been some improvement but only a little.
It does sound like yours is a slower progressing symptom. So maybe autoimmune.
Hi, not related to b12, so if you don’t want to answer that’s fine. Do you have autoimmune issues? If so have you looked into myositis or dermatomyiositis? Or even genetic diseases such as charcot Marie tooth disease etc.?
Hi that's really interesting, thank you. The myositis looks to me mostly muscles best the trunk and my issues are all distal. But the last one - CMT - is interesting as I have very flat feet! However I have had genetic testing which was very broad as I understand it and they said it ruled out any 'known' genetic conditions but not sure if they testing for all genetic conditions... I got the impression they did but who knows! Thank you for your help x
not a genetic counsellor but aware that when it comes to rare diseases it is actually quite difficult to really know the impact of variants - many aren't fully understood and evidence can change so where at one point in time it may be thought that one variant is significant and then it turns out that it isn't, and vice-versa.
Gemini4378. Your active B12 looks to be towards the top of the reference range and you say your MMA is normal?
Functional deficiency is extremely unlikely if your MMA is normal (MMA builds up when there is insufficient B12 OR if B12 is not getting to the cells (that’s the 'functional' B12 bit).
I note that you have psoriasis- an autoimmune disease. Autoimmune diseases tend to arrive in clusters (I have two so far - lupus and psoriatic arthritis) and, perhaps interesting from your point of view - some autoimmune diseases can cause all kinds of neurological issues and various forms of myopathy and muscle wasting.
It might be more beneficial to investigate potential underlying autoimmune disease - perhaps start by asking your GP to run autoantibody blood panel (ANA etc) and then ask for referral to a rheumatologist who can investigate further, if necessary. It’s also worth noting that autoantibodies can wax and wane so worth getting period testing even if all looks 'normal' right now. It’s also worth noting that in the same way as PA can be antibody negative, so can autoimmune disease - so called sero-negative disease (it’s more common than many think).
So…I don’t think B12 deficiency is the cause of your current problems and in view the psoriasis, it’s worth investigating if you have other autoimmune conditions at work.
Also worth considering if thyroid is well controlled - significant overlap between hypothyroidism, B12 deficiency…and systemic autoimmune disease.
Also - if the myopathy and weakness is getting worse and walking is getting increasingly difficult, perhaps your GP could refer you to neurology - a second opinion maybe? Worth a thought and a try if things are getting progressively worse.
As to the 24 x 1000mcg adenosylcobalamin tablets a day - the fact is that your body will expel most of it since the amount that can be physically absorbed from the GI tract is - I forget exactly how much and have no time to check right now - but it’s less than one tenth of one tablet.
I'm sorry you’re going through all this - it seems that we always have to fight harder with medics when the answers are not easily found - please keep at those medics and fight for answers - because there will be some - all you need is a medic who will look and think hard enough.
Thank you for your response. I'll look oni those tests.
I've been with a neurologist for 5 years and have just moved so seeing another one now and it seems that I've had all the tests they offer and they just want to see me every year to monitor it and that's it. Been waiting 7 months for a new physio. Basically zero support in getting further answers unfortunately from consultants or gps but thank you for your encouragement to keep fighting, sometimes it's nice to hear it!
My experience of neurologists is that they’re not interested unless you have a ‘Big hitting’ neurological disease (their clinics are so overloaded so I suppose they have to priorities - but not much fun for those who aren’t big hitting).
I eventually discovered that my neurological symptoms were / are due to lupus (progressive small fibre neuropathy and autonomic dysautonomia), so definitely worth investigating autoimmunity.
Keep strong, take care and good luck. I’d be interested to hear how it goes x
P.s did the neurologist test you for neuro autoantibodies? If not, perhaps ask them to do so when you next see them x
You're only expected to absorb about 1 % of 1000 mcg b12 tablets, so 24 tablets would correspond to approximately 240 mcg, less than a 1000 mcg injection. Actually, only an estimated 30 % of a 1000 mcg hydroxycobalamin injection is retained in the body, so the 24 tablets seem to roughly correspond in strength to one injection.
Not sure why the adenosyl form, but I'm guessing it could be a way to avoid the cyano and methyl forms. Some people don't feel well on the methyl form, and the cyano form may not be as well retained at such a high dose.
Perhaps the tablets were suggested because they can't give injections.
The absorption rate of oral B12 is limited, in any one 'dosing session' - no matter how many tablets are taken at that time (because uptake via the terminal ilium is limited to how much it can 'grab' and process as the B12 slides past on its journey towards the large intestines) - plus whatever happens to be absorbed via passive absorption (or not) in the GI tract). When multiple tablets are taken it’s not possible to gestimate how much will be absorbed - though it’s not likely to be much more than 10mcg per 'dosing session'. The body does not (cannot) absorb equal amounts of B12 from each tablet (oh if it were only that easy) - and the excess is expelled via the usual GI route (absorption via the terminal ileum is a bit like a sponge, no matter how much water your pour on it, it can only absorb so much - the rest just leaks away - and we know where it pops out). This is also assuming that there are no absorption issues - some are unable to absorb any B12 from oral supplements, however many they take.
As per above, the 24 tablets do not equate to one injection. 100% of an injection is absorbed. The clearance rate for injected B12, via the kidneys, varies for each individual. Injections deliver high doses (all the dose) immediately and thus raise B12 levels and start the repair process much more swiftly than oral supplements. This is vital where neurological symptoms are present (and hence precisely why all the guidelines specify injections when neurological symptoms are involved. The fact that many GP’s don’t know this is a different issue.
The different routes used to deliver B12 and the individual variables involved make it nigh impossible to equate or calculate an equivalence of dose via the different methods of delivery, oral v injection. And injection is always swifter, with the guarantee that the full 1mg enters the body directly (via the blood stream).
So why do they sell 5000 mcg b12 tablets? The way I understand it it's the efficient, IF-mediated uptake that is limited to approximately 10 mcg at a time, while "passive" uptake is estimated to 1 %, independent of dose.
Yes - but what you say demonstrates what I'm saying: that the amount of B12 absorbed via the oral route is only a very minute % of the actual oral dose taken - no matter how many tablets are taken or at what dose. And the uptake is also limited, in part, by the variables I mention above (not least how much the terminal ilium can process).
The bottom line is that there is no 'exact' science about this - where oral doses of B12 and uptake is concerned, peer reviewed research suggests 1%-3% in total - via IF mediation and passive absorption). For many, B12 uptake from orals will be nil.
Uptake via the oral route can never achieve the same B12 'load' (for want of a better way of putting it) as a B12 injection, due in part to the variables involved and the amount that can be 'taken-up' at the terminal ilium.
So, there' no exact science about this - it’s never possible to say that x number of tablets at x dose will be equal to a B12 injection of x dose (which is what I think you were suggesting). Oral supplements can never achieve (or even approach) the b12 uptake found with injectable B12 (always 100%): there's no equation that can 'give-up' precise 'quid-pro-quo' dose correlations between oral and injectable B12.
'Exact' science fails to provide answers for so many things B12 related, for instance:
Some with absorption issue are able to change to high dose supplements once symptoms have been controlled via B12 injections (one PAS member keeps symptom free by taking high dose oral supplements - and runs marathons). But orals don’t work for everyone - many have to stay on injections to remain symptom free. Nobody knows why orals work for some, but not others.
Equally, nobody knows why some need injections much more frequently than others to remain well (much more frequently than the 8-12 weekly maintenance dose currently prescribed ). Again, nobody knows why.
We all know that B12 levels are meaningless after any form of B12 supplementation - so there’s no direct correlation between B12 levels and wellness (i.e. staying symptom free). Though most doctors seem to think so. Again, no 'exact' science or correlation between B12 levels and symptom relief (studies that ‘investigated' the uptake of oral supplements suggested that B12 levels went up they did not assess assess whether symptoms improved (i.e. the efficacy of oral treatment).
So many unknowns about B12 deficiency and it’s treatment, the efficacy of oral supplements (or not), and the variable frequency of injections required to maintain health. These are things that the PAS are currently researching - so answers may eventually be forthcoming.
Which brings us back to where we started…trying to work out oral dose and precise absorption rate and arrive at a oral dose that is the equivalent of a B12 injection is just not possible.
The bottom line is:
Oral supplements can never deliver the same B12 dose as a B12 injection - no matter the number of tablets or the dose of each.
B12 injection - it all goes in - all 100% of it 🙂.
Sorry if I've made this sound complicated - it is - but it’s also not (if you get what I mean).
In conclusion - oral supplements never worked for me - however high the dose taken. I need to inject B12 at least weekly to remain symptom free. There isn’t any science to 'explain' me
Apologies if I've failed (again) to make this intelligible. I know what I mean, but it’s not always easy to say what I mean (Foggyme) 🙂.
The receptors for the b12-IF complex are located in terminal ileum, but the impression I have is that passive absorption doesn't make use of these receptors, and is thus not restricted to where these receptors are.
Found this:
Historically, this passive absorption mechanism provided the first treatment for pernicious anaemia.1,2 In the absence of an intact ileum or intrinsic factor, 1.2% of an oral dose of vitamin B12 will pass across the small bowel.3,4 The dose absorption ratio is remarkably constant in an oral dose range from 1 to 100 000 μg of hydroxocobalamin
pmj.bmj.com/content/79/930/218
Not sure if the result is the same for other forms (not hydroxy) of b12.
I thought passive absorption wasn't restricted to terminal ileum.
I'm not saying that it is!
I'm saying that there are TWO methods of oral absorption: via the terminal ilium AND passive absorption (which takes place in the GI tract (small intestines).
The fact remains that one can never get the same B12 dose delivery via oral supplements as one can achieve from a B12 injection (what you were saying earlier and what I am saying is not possible).
It’s pointless to debate or quibble about exactly how much of an oral dose is absorbed - because nobody can be precisely sure - best approximates are between 1- 3% of the oral dose taken - at best: a minute amount and significantly less than the 100% absorbed from a B12 injection . And oral absorption will be none for some people - there isn't a 'rule' that fits everybody (inflammatory bowel / those who have had portions of their intestines excised). Whether oral supplements are effective is an entirely different debate.
A significant point here is that the research findings that suggest the 1% - 3% absorption via oral supplements failed to assess efficacy - nobody expolered whether this actually worked to alleviate symptoms. And that’s a big issue because GP's are withdrawing B12 injections purely on the assumption that some of the B12 is absorbed - with NO idea whether it works to alleviate symptoms. Furthermore, patients are given no choice and when they report that symptoms are returning when on oral supplements, few GP's believe them and refuse to reinstate injections (they gaslight and disbelieve their patients). So there is significant potential harm being done to patients because of misunderstanding about how that research was conducted and what the result actually 'mean'. And that is utterly disgraceful.
I fully agree that injections are better for many and that thepercentage absorbed is much less for tablets. You'd have to take a much larger dose as tablets to absorb anywhere near the total amount you keep from an injection.
But I also think the percentage retained from injections means something. The numbers I've seen are 30 % of a 1000 mcg for a hydroxycobalamin injection and 15 % of a 1000 mcg cyanocobalamin injection. Which is why standard maintenance treatment to prevent deficiency typically is (in US) cyano once a month and (in UK) hydroxy every 2 to 3 months. Smaller doses are better retained, like 90 % of a 100 mcg hydroxy injection.
Of course there are individual differences regarding everything, I just thought the numbers might be a rough guide.
It is not possible to ‘near the total amount you keep from an injection’ by taking oral supplements. Even huge amounts.
100% of a B12 injection goes in - the rate it is expelled varies hugely in each individual and the overall retention time also differs.
Trying to compare oral doses with injected doses is like trying to compare apples and oranges.
In this case, the numbers are not a rough guide to anything - unfortunately. The numbers are essentially meaningless because the ‘numbers’ (or a number) tells nothing about efficacy of treatment.
The question that should be asked about B12 is not how much goes in, or how much is retained - that’s a mistake many researchers make (having a certain B12 level, after injections, does not guarantee ‘successful’ treatment - there’s no ideal or optimum B12 level at which B12 deficiency can be said to be effectively treated). We see this in action all the time when GP’s stop treatment because levels are in the ‘normal’ range (or what they seem too high), despite the continued presence of symptoms! The mantra should be ‘treat the symptoms, not the numbers’.
This is (partly) what I mean when I say that the numbers are meaningless.
The right - the only - question that really matters is - is the B12 working! And knowing the dose absorption or retention rate can never answer that question.
Evidence based medicine - including (but not limited to) a focus on B12 ‘numbers’, is resulting in irreversible neurological damage - even death - for far too many.
I’m aware that I’m probably pushing your points further than you thought or intended, but I hope you’ll see why. 🙂
I'm not comparing a 1000 mcg injection to a 1000 mcg tablet.
I don't see why 24x1000 mcg tablets with an estimated absorption rate of 1,2 % shouldn't be comparable to a 1000 mcg hydroxy injection with a retention rate of 30 %. I'm not saying they are identical or that one thing always would work as well as the other for everyone. But I think the doses are comparable according to available information.
As others have said we’re not doctors so don’t know and your symptoms don’t seem typical. If you think it’s B12 take it and see if you improve- try sub-lingual tablets. Then at least you know for sure. If it started in Thailand I would go to a Tropical diseases specialist. I picked up something abroad and it took a year to find someone by going privately that said yes you’re sick physically and treated me. The advantage is that they love the unknown too!
Hi, thank you for your response. I think I mentioned in my post, I have been to tropical disease clinic and they didn't find anything apart from EBV which a huge number of people have in the UK.
I agree that many have, or have had, EBV, but for those who have a predisposition to autoimmunity along with the other triggers, its effects can be considerable. It has been connected to thyroiditis for some years, and increasingly to other autoimmunity the-rheumatologist.org/arti.... (You can test privately for autoimmune antibodies if you really need to, should you have funds available). Best wishes
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.
but thank you for your encouragement to keep fighting, sometimes it's nice to hear it! 
Functional B12 Deficiency?
On a standard b12 blood test my levels are normal can I still be b12 deficient?
Any connection with B12 deficiency and Bladder issues?
With normal levels of b12 can you still be deficient 
