B12 and magnesium supplements

After a break of quite a few months (due to waiting to see neurologist and not wanting to skew any blood tests), I have gone back on the above supplements and am taking 2 x 1000mcg B12 nuggets and 4ml of Mega-Mag ionic magnesium in a glass of water, once a day. I tend to have both of these in the evening so as not to clash with my thyroxine.

Just wanted to double check that these supplements are quite safe in the above amounts. Am I right in thinking that any excess is just washed out naturally?

15 Replies

  • Can't comment on the magnesium but the B12 won't be a problem - not something you can overdose on and nobody has ever identified any problems with taking or having high levels of B12.

    Don't know if you know what your folate levels are but you might want to consider supplementing this as well as you need folate (B9 to be able to fully metabolise and use B12). A good vitamin B complex should do the trick - though you do need to watch your B6 intake as doses over 100mg a day over several months have been linked to neurological problems - which generally go away after supplementation stops but there are some cases where this didn't happen

  • Thanks for your reply. Last result I have for folate is 10.8 (so well within range) and 268 for B12, which according to many people is on the low side.

    Just hoping that taking these two supplements will stop the tingling.

  • B12 is well into the grey area.

    Has your GP discussed B12 deficiency with you at all? and loading shots and maintenance shots?

    Do you know if the tablets are methylcobalamin - usually are - which seems to work well with neurological symptoms for most people - but even so people do respond differently to different forms of B12 (cyano-, hydroxo- and methyl) so it might be worth trying another format if the tingling doesn't stop - or even trying a higher dosage - as you can't overdose.

    I seem to need to keep my B12 off the top of scale to avoid symptoms.

  • Hi Gambit, I was interested to read about the B6 'overdosing' being implicated in neurological damage. I've never heard of this - do you have any references for it, or can you remember where you read it? I'm asking because during the 80s & 90s I took high doses for many years (it was supposed to help with period problems when combined with magnesium; it never did!).

  • ncbi.nlm.nih.gov/pubmed/163...


    Can't find the reference to permanent neurological damage at the moment

  • Thanks, Gambit. Although that makes really depressing reading. Annoyingly I can't remember exactly how much I used to take. I know I used to specialist buy it to get higher dose tablets. Damn. If ever there was an advert for not doing prophylactic vitamin-taking, this is it. I'll have a nose about and see if I can find anything. Although not sure what the hell I could do about it now!

  • There was a lot of publicity around B6 overdosing in the 1990s, if I remember correctly - which was the point at which medics really started coming out and saying that any form of supplementation was a bad thing ... which is why I have always been very careful about B6.

    Believe EU has set safe upper limit at 25mg/day - think UK is even lower, though US has 100mg ...

    Came across this link - don't know if there is one that is a bit more up to date ... would hope so as some of the bits under B12 about symptoms of deficiency and defining characteristics are depressingly misleading - the old chestnut of anaemia..


    Very weighty tome so may take a while to load :)

    Not very kind to the idea of supplementing magnesium - concludes that it's impossible to set an upperlimit because of incidence of diarrhea caused by supplemention. So guess that makes it a bit of a try it and see thing.

  • That is an incredibly informative document - more or less a definitive go-to encyclopaedia on vitamins, thank you. I find that nearly every book that even vaguely touches on nutrition recommends one kind of supplementation or another. I find it very off-putting and it makes me mistrust the author. Some of them have you so supplemented it's almost a new illness! I used to be a regular supplementation person right through the 80s right up to the early 2000s when I finally lost patience with 'quack' cures (I tried a lot of alternative medicine in general) and I realised none of it had made the slightest bit of difference - other than to my wallet! It takes a lot to convince me nowadays that a disease has one nutritive cause. I think the human body is FAR more complex than that. I don't believe in messing with just one part of a system. That's one of the things that comforted me about having B12 treatment - it wasn't going to do any damage. Although I have treatment, I made big changes to my diet at the same time in the hopes that I will become properly self-sufficient again in time (I don't have anaemia, obviously).

    Thanks again for the vitamin 'bible'. I'm going to have a real in-depth rummage in there!

  • GP says B12 level is absolutely fine. I am taking the Solgar sublingual methylcobalamin 1000mcg, which I believe is one of the best ways to take B12. Was taking two in one hit, but today I have started having one in the morning and one in the evening. Have also split my Mega-Mag to 2ml twice a day. So fingers crossed should see some improvement in the next week or so.

  • Really sorry to hear that your GP isn't aware that your B12 is actually in the grey zone so you could be suffering from deficiency

    Don't know if this will be of any help in dealing with your GP - NICE guidance on interpreting B12 serum test ... though it isn't as clear as it could/should be


    Hope the sublinguals work and you start to feel better soon.

  • This might also help as it is somewhat clearer

    it's a long document but the relevant bit is the Summary of Key Recommendations at the beginning


  • Hi Twitchen, your B12 definitely isn't "absolutely fine". If you lived in Japan you would be considered well under normal and would be treated for deficiency (their figure is 500 for normal). Likewise most researchers and specialists in B12 deficiency believe the figure should be around 400 - 500. You are definitely not fine. Just passing muster, I'd say, and that's only providing your body doesn't need more than the recognised normal of 400 - 500!

  • Thank you Gambit62, that is very informative.

  • My understanding on magnesium is that you'll know when your body has gotten too much because it will cause diarrhea. B12 is water soluble, so no worries on that one except that large amounts of B12 can lower potassium. You may want to make sure you are eating foods rich in potassium for a bit until you're body gets used to the level of B12 you're taking.

  • Strangely enough on the blood tests done last year my potassium level was 5.1 (normal level 3.5 - 5.0), so a bit on the high side.

    I think for the next couple of weeks I will stick to the 2000mcg B12 and 4ml magnesium and see what happens. I vaguely remember somebody saying it is a good idea to take folate alongside B12, but again my folate level was absolutely fine.

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