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Thyroid UK
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Freaking out! Looking for clarification

Hi everyone

I started on 25mg of levo about 6 weeks ago (I know, stupidly low dose, but the doc wouldn't increase it until my next bloods) and have, understandably, seen no improvement. However, after hunting around on the internet, my attention has been drawn to the few other tests that were taken at my last bloods - b12 and ferritin. My b12 was 238 ng/l (197 - 771) and ferritin at 139ug/l (30 - 400) which shows as lying within normal range, so at first I thought nothing of it, but after further investigation it seems that b12 should look more like 500+??!

I've been having spells of brain fog for a while now, way before my diagnosis, with differing levels of severity (when it's been bad it's been pretty damn bad) and I'm starting to worry about any permanaent neurological damage - I'm 21 so I know this is unlikely, but then again I don't know how long I've been hypo for, so the idea that my brain is somehow underdeveloped thanks to nutritional deficiency has embedded itself in to my head

On the other hand I know that overthinking and the internet is a dangerous combination, so I thought I'd pass this one over to more knowledgeable, rational people :')

How likely is it that irreversible damage has been done? I understand that B12 injections won't be administered by NHS for a result of under 200, what would be my next best option? Also, I want to ask for a more conprehensive blood test when I go back in a few weeks so I can get a proper understanding of any deficiencies taking priority - what should I be asking for?

5 Replies

You are correct your B12 is low. You can supplement with B12 sublingual methylcobalamin and I find that Amazon has the best selection. Many pharmacists don't stock methylcobalamin only cyanocobalamin.


The recommendation for B12 is now 1,000 and you cannot overdose as excess is excreted in urine.

You symptoms are most probably due to being hypo and as your dose is increased symptoms should disappear if GP knows how best to treat you. If not the members on the forum are expert and will advise you as you go along.

Don't worry about neurological damage as that would probably take years and you are young.


Blood tests (GP or lab may not do all of them but we have private labs) TSH, T4, T3, Free T4, Free T3 and thyroid antibodies. B12, Vit D, iron, ferritin and folate.

Blood tests have to be at the very earliest, fasting (you can drink water) and allow a gap of 24 hours between last dose and test and take afterwards.

Always get a print-out of the results with the ranges and post for comments.


Thank you so much! Gonna go grab myself some from Amazon right now :)

I'm also gonna look in to the private test, as I'd really like to have as much data as possible - any idea how much usually one costs?


Yes unfortunately your B12 and ferritin are both too low. You can supplement B12 via sublingual tablets, 5000 mcg dose daily. It'll still take quite some time to haul that B12 up to an optimal level, though. Ditto with ferritin, you can take iron supplements, such as ferrous fumarate or ferrous sulphate (some folk tolerate one type better than the other), at 210 mg x 3 daily for a couple of months, then re-test.

As for how likely irreversible damage has been caused, it's hard to say. Do you have any other symptoms of B12 deficiency, e.g. peripheral neuropathy (numbness/tingling in fingers/toes) ?

Have you had folate tested? Vit D? Both of those also need assessing too.

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Ordering both now, thanks so much

& I remember I did used to get some tingling in my right arm a few years back, but that's stopped now and I've never felt any numbness. Assuming unrelated?

Folate has never been tested, neither has vit D although I have been supplementing with 1000 iu for a few weeks now

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If you can't get full thyroid and vitamin testing from GP


Medichecks Thyroid plus ultra vitamin or Blue Horizon Thyroid plus eleven are the most popular choice. DIY finger prick test or option to pay extra for private blood draw. Both companies often have money off offers.

All thyroid tests should be done as early as possible in morning and fasting and don't take Levo in the 24 hours prior to test, delay and take straight after.


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