Log in
Thyroid UK
93,414 members107,474 posts

Vit b12 overdose

Had new blood tests Monday and doctor phoned and Said to stop taking supplements and retake tests in 2 weeks so went to get the bloods forms and it said reason for blood retake was very high vit b12 results and there was also an test for liver function this time.I was under the impression you couldn't overdose on b12 my last results were b12 298 which was the low end of normal but the receptionist wouldn't give me b12 results she said she didn't want me to google it.I had been taking 5000mcg for the last 3 weeks and 1000mcg for 3 mths before that.But I had been feeling so much better.

8 Replies

And what medical qualification does this receptionist have to be giving you medical advice?

They are blood test results and you are entitled to see them or have a printout. Was it the doctor or just some one from the surgery that told you to stop taking these supplements?

I would be asking for the doctor to phone me and discuss the actual results, not the receptionist, and I would also would want to see the results in black and white, along with the relevant ranges and then I, not the receiptionist/doctor would make up my own mind if I wanted to stop the supplements.

I would also be telling the doctor and receiptionist, that unless I see these results then I will continue to take the supplements meanwhile, and please add into my medical notes my decision for this and why. x

1 like

I have read that our B12 range in the UK is too low and these are some links which will confirm this.


Your GP may be querying the rise in your B12 but you can tell him you have been supplementing.


I agree with every word boo16 wrote. Also with shaws' point that the UK b12 range is too low, exactly what I was about to say but was beaten to it. Professors D Smith and H Refsum (Oxford) also say that neurological symptoms can occur at much higher levels than the bottom of the NHS reference ranges. There is no such thing as a "normal" result, only results within or without the reference range. For any GP to say "normal" perpetuates the idea one size fits all. At 298 you probably felt tired and washed out but that figure is above the much too low bottom of the NHS range so no GP would find it worthy of notice. Now you feel well, your level is probably above the top of the reference range so your GP has panicked. I just wonder what the B12 level was.

What then about the high measurements treated PA patients exhibit - more than 1500 on injection - are they all going to keel over?

The only form of B12 likely to carry any risk is cyanocobalamin and that risk is not with regard to overdosage, cyanocobalamin is contraindicated for those with Leber's disease. an eye problem, and those who smoke, it has to do with the cyanide molecule indicated by the term "cyanocobalamin". Methylcobalamin is the preferred form for supplementation and as a member of the Pernicious Anaemia Society I have never read there that reasonable supplementation carries any risk.

On a personal note I also supplement and monitor B12/folate privately,( £30 ) keep my levels at around 1200ng/L, where I feel best.

1 like

I inject WEEKLY with methylcobalamin, I don't do a blood test for B12 as I already know it WILL always be OUT OF RANGE :D

have a look here (my doctor's website):


I would find it HIGHLY offensive that the receptionist declines to tell me MY result as I would 'google it', HOW DARE SHE??? they are MY results and it's MY BODY.


1 like

Exactly what I was thinking. Who the hell does she think she is that she can tell people they mustn't google! Talk about jumped-up, tin-pot dictators. I would have had a few sharp words to say to her!!!


Have just started on B12 on recommendation of homeopath after vega test - NHS say I'm fine but vega machine disagrees. Thanks for all this info and good luck Vanessa with your dragon receptionist. Mine wouldn't let me have the reference ranges even though I'd paid for the results. The GP eventually put it right - hurrah :-)


I have B12 injections every 2 weeks and the last time they actually tested to see what it was doing, which was part of a whole host of other tests it was around 2000 and no one batted an eyelid!! That was around 2 years ago and they are still giving me the injections!


I too have just had my B12 results this week and they state out of range. I have been using B12 supplement for a few months as well as B complex. I have just read that using the B complex affects the B12 test? I do not know if this is true? My results are as follows:

Serum Vit B12 967ng/L (187 - 883)

Serum folate above 20ug.L (1.8 - 18.3)

Serum ferritin level 99.4 (10.0 - 204 .0)

T4 12.5 (9.0 - 19.1)

TSH .92 ( .35 - 4.94)

Regrettably my peroxidase was not tested on this occasion (an oversight) although this has been constantly above 1000. I am disappointed as I was hoping to see some reduction due to supplement and a not totally successful attempt to go gluten free. My actions have been based on my experience of others on this site!!!!

In addition to B12 and B Complex and a multi vitamin, I take Selinium. I have always used supplements. I am debating with myself whether I should take vit B12 alternate days? Is this appropriate.....


You may also like...