B12 overdose symptoms

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Hi, I started taking 5,000mcg thinking extra b12 would be harmless about 3 weeks ago everyother day. Apparently not, my arms and legs went numb and tingly first I went to the doc. Never said anything about b12 gave me methylprednisolone and meloxicam. I had continued taking the b12 I assumed it was a "healthy" thing. Went back in for a check up and the NP tested my b12 my level was 3 times the normal amount at 1853. She thinks everything is coming from the b12. I now have slight tingling in arms, side of face, muscle weakness, cramping tummy, and joint pain. Does anyone have similar issues and how long until I get the b12 out of my system, coffee and water is going strong. It's been 5 days since my last b12 tablet.

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  • Posted

    Why did you start taking B12 supplements in the first place?

     It is normally only prescribed for people who are B12 deficient or have Pernicious Anaemia although sports persons asre know to take it to "boost" their energy levels.

    I am not a medically trained person but I've had P.A. for more than 45 years and without regular injections of Vitamin B12 I would have been dead 43 years ago and I'm now 76.

    Below is an extract from a Dutch paper saying how safe it is.  You cannot "overdose" on B12 as any excess is excreted via your urine.

    Treatment with high dose vitamin B12 been shown to be safe for more than 50 years

    Out of fear of overdosing vitamin B12, treatment is often reduced to below the frequency that is needed by the patient, or, even worse, treatment is stopped completely.

    As a result, symptoms can reoccur again and again and even become irreversible.

    It is very clear this fear of overdosing is based on a misunderstanding. For over 60 years high dose vitamin B12 treatment has been used without any signs of the danger of an overdose.

    The Dutch National Health Counsel and the Regional Disciplinary Medical Board of Eindhoven have stated clearly that vitamin B12 is non-toxic.

    Clinical research and the treatment for cyanide poisoning have shown that even extremely high doses of vitamin B12 and the serum values that go with it are harmless.

    A decennia long history of safe treatment

    In 1926 it was discovered that patients with pernicious anaemia could be saved from a certain death by eating a pound of raw liver a day. More than 20 years later the substance that was responsible for that was isolated from liver extract: vitamin B12 or cobalamin. Since then numerous patients have been treated with high dose vitamin B12 worldwide. Usually per injection and often lifelong, as a deficiency is mostly caused by an irreversible absorption disorder. In all that time harmful effects have never been shown from overdose. No single case has been found in medical literature in the past 60 years.

    No maximum dose

    The Dutch National Health Council therefore decided not to determine a safe upper intake level for vitamin B12. In their report from 2003 “Voedingsnormen: vitamine B6, foliumzuur en vitamine B12” the council joined expert commissions from the American Institute of Medicine and the Scientific Committee for Human Food from the European Union, who had already reported 3 years earlier that toxicity from high dose vitamin B12 poses no real danger.1

    Of course, like with any medical treatment, side effects can occur. Acne, eczema and itching seldom occur and very rarely anaphylactic shock. Changing brands of vitamin B12, forms of B12 (cyanocobalamin vs hydroxocobalamin), or switching from injections to tablets can be a solution in those (rare) cases.

    Misunderstandings about blood and reference values

    Yet often physicians reduce injections or even stop treatment altogether out of fear of overdosing B12. The result is that many patients are left with recurring or lasting symptoms, which could be relieved by more frequent injections. After an injection the serum B12 value rises quickly, well above the upper reference value (on average 150-700 pmol/L), followed by a slow decrease. Apparently the underlying thought is that it is necessary to keep the value between the (upper and lower) reference values. However the blood level of serum B12 rises regardless of therapeutic effectiveness.2

    A high serum B12 value does not mean that symptoms are treated sufficiently. This presumption can have damaging effects for patients with neurological symptoms, which can become irreversible with insufficient treatment. 

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  • Posted

    Hi Dani.

    as you'll have read in 'clivealive's' comprehensive response, B12 is totally non toxic. for example my ''SERUM'' levels are off the b12 measuring graph i.e. above 2000 and I'm fine. the results that your Doctor has given you is the amount of b12 floating around in your blood stream. the amount in your blood stream has NO significance. what's important is the amount that reaches your actual cells.

    unfortunately, there is NO ''accurate'' means of measuring how much b12 reaches our cells. only 20% of the b12 we take in is ''active'' i.e. the amount that actually gets through to one's cells. therefore, 80% of what we taken in is inactive.  b12 treatment deficiency is assessed by the presence or absense of b12 symptoms. what you desribe in respect of symptoms suggest ''neurological'' symptoms that could be due to b12 deficiency or a number of other medical conditions.  it is CERTAINLY NOT due to b12 toxicity as  no such condition exists.  what's important right now is firstly to know what your b12 levels were prior to your b12 supplementation. and then if your symptoms persist & are life limiting, do get a refferal to an Specilist either a Neurologist or a Haematologist. unfortunately, gnerally speaking GP or Primary Health Care Practitioners are very poorly informed in respect of b12 problems. 

    if you live in the UK the Pernicous Anaemia Society are very helpful. do give them a ring - 01656 769717.  a very helpful book on b12 deficiency is ''Could it Be B 12 - An Epidemic of Misdiagnosis''  by Sally Pacholok & Jeffrey J Stuart''. an excellent forum is ''Healthunlocked'' the PAS section. 

    hope all goes well for you.


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  • Posted

    Hi Dani,

    I experienced exactly the same as you after b12 injections. My gp wouldn't take me seriously when I said I thought it was the b12. I've since spoken to a few people with the same problem. Just because you can't overdose on b12 doesn't mean there are not side effects. My symptoms have still not completely resolved. It's just a question of time and drinking plenty of water.

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  • Posted

    High B12 doses may not be toxic in themselves, but I believe you can get hypokalemia from excess B12 if you are not getting enough potassium in your diet. Symptoms of low potassium include tingling and numbness.
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  • Posted

    Hi daniyelly27,

    ?I had major problems with taking high doses of B12 2,5 years ago. When I started taking them I only had some numb and stinging feelings on my skin, and I had had difficulties walking 1 year before that. My B12 was on the low side, but not deficient. I took 1 quick-melt tablets of Methylcobalamin 10.000mcg and 1 quick-melt tablet of Adenosylcobalamin 10.000mcg. After 3 days already I started feeling really sick. I quit for a while, to start again 2 weeks after that. After 3 more days I quit permanently. I felt horrible. Before taking the tablets I felt healthy fo 95% but after that I felt scarcely alive. I had about 40 symptoms; I lay on the couch all day because of extreme exhaustion; I couldn't lift my arms or do any movement normally because all of my muscles were permanently acidified; 24/7 I had an extreme metallic taste on my tongue that made me very nausious; I had crazy still unexplainable "rushes" through my body that lasted for hours and were extremely scary and traumatic. And many many other symptoms. For the next 1,5 years I was afraid I would die. I cannot overstate how dreadfull my condition was. I was doing buddhist practices to prepaire myself for dying and trying to let go fear during these rushes. I still don't have clear answers for what happened. Theories that I've come up with so far include: damage to my nervous system due to a too rapid heavy metal detox (hence the metallic taste and neurological symptoms) since B12 methylates? heavy metals such as mercury; and Lyme disease. A Lyme specialist thought about this as well but says no test is reliable for my situation, so I shall never truly know. However, possibly the B12 methylated with heavy metals and this in turn created weakness in my immune system so that an old Lyme disease that I had 8 years ago suddenly came back.  

    ?Even when people say "side-effects" can happen, it is the severety of these side effects that determine whether you can overdose. For me however, those were not just side-effects. Something else had gone terribly wrong. So whether those were side-effects for me or not, it was definitaly a B12 overdose. Normally scientific studies, such as those looking at whether B12 can be overdosed, are carried out on healthy patients. Perhaps perfectly heatlhy patients cannot have an overdose, but no-one is perfectly healthy. Everyone's body has weaknesses or some viruses or bacteria floating around. Sorry for the long story; I just want to tell you my story as an example of how complex the body is. From my experience I think it is rubbish to say that a B12 overdose is impossible. The body is extremely complex and any triggers (such as B12) will start a whole chain of changes in your body; some are good changes but some might be bad, such as too rapid detoxing. That some studies showed that high doses of B12 aren't harmful doesn't mean that 100% of humanity has only positive or neutral responses to B12.

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