Thyroid UK
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drug free blood test

I've decided I'm fed up with waiting for the gp to do something meaningful and I want to self medicate.

My B12, at the last blood test in November, was 284 (190-900) but the gp didn't offer me anything. I asked for B12 and he's given me 50mcg (yes - mcg) tablets which, as someone on here said, would be no good in my lifetime!

However, I thought I'd go along with it and wait 2 months (he said 3) to have another blood test when, hopefully, he would give more beneficial treatment. I've decided I can't wait another month and after one month I feel no different at all on these tablets.

My question is this, if I get some of the Jarrow (is that right?) methylcobalamin, maybe 5000 to start with, how long should I go without them before the blood test the gp wants me to have? How long does it stay in your system?

Thanks everyone - don't know what I'd do without you all :)

3 Replies

Once on B12 supplements any testing is worthless. The results will be skewed as it can remain in the system for months. This was explained to me by Martyn Hooper - Chairman of the PAS - whilst discussing my grandson. Anyway it's not what is in the blood that is important - it's the amount that reaches the cells where it is needed. The Active B12 test can do that reading - a private test done through St Thomas's hospital I believe. You do not have to cease taking B12 with the Active Test.

You could just assume you are deficient and always take a supplement..... better to be safe than sorry.

I would take the 5000mcg Jarrow Methycobalamin. Also take a good B Complex to keep all the B's in balance. I take Thorne Research.


Would the supplement not skew the active test as well? I don't know how that works :(

Also, is the Jarrow one sublingual as I hear that's better?


No it does not skew the Active Test. If you would like confirmation then contact the hospital lab yourself for reassurance :-)

Yes Jarrow is the sublingual one.....


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