I'm hypothyroid with lowing B12. How much B12 s... - Thyroid UK

Thyroid UK
101,655 members116,514 posts

I'm hypothyroid with lowing B12. How much B12 should I take?

I have purchased (and they are in their way) the jarrows 5000 sublingual B12. How much should I take and how often. In previous question I posted that my B12 levels have been 180, 226 and 205 over the last 2 months but dr is adamant these are normal with the exception of the first which she said is spurious. I have a haematologists app on 28th but apparently they will look at historical results, I have been off work for 8 weeks and signed off for another 4 but I just get back to normal. Now on SSP and not easy to manage so am going to start taking and hope that makes a difference. I will let the haematologist know what I am taking but need to do something.

16 Replies

I think it will have a recommendation on dose on the bottle. Usually it says take with meals.

You cannot overdose with B12 as excess is excreted in urine. I get injections of B12 and at times my level has been 2,000.

I hope it does the trick and you feel better quite soon.


I have ordered from big it's and it's says to take one tablet every 2/3 days it as advised. But I read on here somewhere that's someone was taking one every day for the first bottle and then started reducing to 4x 1000 gradually down to 1000 every couple if days, I think but can't remember where I found it! Hence my confusion but good to know that u can't overdose.


I did something similar. I started with 5000mcg a day for the first bottle then went to 1000mcg 3 times a day for a couple of weeks, then 2 a day and now I'm taking 1000mcg once a day. I am intending to stay with 1000mcg once a day unless I have been ill or start experiencing symptoms again.

I hope that helps

Carolyn x

Oh and do listen to hampster1 and wait until you have seen the haematologist first before supplementing in case they want to do tests :)


Thyroidseb, please don't start supplementing yet, at least see the Haemo first. Your B12 levels are so low every time, I would plonk myself down on the chair and refuse to leave until they agree to do further testing. You're hypo, so way more likely to have PA, please get some more tests. I've put some links in another answer this morning, see here:


Just to clarify, tests your Haemo could run are as follows:

- Anti-Intrinsic Factor

- Anti-Parietal Cells

- Active B12

- Methylmalonic Acid (MMA)

- Homocysteine

Insist that you are not prepared to be assessed on the basis of the serum B12 test, as you are aware that there is a warning issued about its inaccuracy:


And also that it is well documented that B12 deficiency can occur with normal serum B12 results:


Don't think that the Haemo appointment is going to be a waste of time, use it to your advantage. But if you start supplementing before it, and they decide to do more tests, then you're not going to get anywhere.

H x


Thanks for these links, H. Treatment of my Hashis helped a lot, but I still had a lot of neurological symptoms - loss of joint position sense, loss of skin sensation, poor balance, tremors etc and B12 at 223. After an initial suggestion of MS, a second neurologist did a whole battery of blood tests, conductivity tests on my nerves etc, but still came up with no idea of what was happening. Because of what I'd read here on HU I supplemented with large doses of Jarrows 5000mcg B12 and gradually ALL of these problems have resolved. If I'd had that ukneqas link to put to the neurologist, maybe I could have had injections and been better sooner. Still, I did feel he was very thorough - I think anyone with these types of neurological symptoms should try supplementing even if proper medical investigations haven't flagged up B12 deficiency.


I'm glad you are feeling better and that the sublinguals work for you, unfortunately they don't work for everyone which is why I'm always quite vocal about exhausting all avenues for a proper diagnosis first and foremost.

I have to disagree about your neurologist being thorough - for a start he's ignoring a B12 result of 223, so what was wrong with you was staring him in the face. It certainly doesn't always show up on MRI's and things like that, so I'm not surprised he couldn't find anything specific. But actually did he do the Active B12, MMA and homocysteine tests on you? I'm guessing no. They'd really save the NHS a bunch of money if they actually started with some proper blood tests. It's not rocket science.

H x


Good advice, H.

What planet are some GPs from?

200 is way low and to write off one lower without substantiation is just wrong.

Get some new advice and walk from the old, I'd say!

it might be worth checking old Folate results if you have them, this being high >20, can show long standing uptake problems -included in above tests.

Keep fighting for your health!


I have 3 folate readings, to go with the 3 B12 readings, they were 10.1, 9.7 and the latest 8.3. This has been since end of August.


If you watch the video below you'll be up to speed! You will use Folate in B12 uptaking but have a fairly good level to start with. keep an eye on it when you do take the B12. Drs don't seem to do enough tests on the side elements needed unless they're clued up.

Not sure what your symptoms are, though?


Fatigue, lethargy, mood swings, can't sleep, forgetfulness, dry skin especially scalp, breathlessness, funny heartbeat-not sure what it's doing just feels 'wrong' that's off the top of my head!


Mostly HypoT, then.

Getting the B12 right [>500+] will be a big help in treating the thyroid and boost your general health too.

I know you have a wait now- but being one step ahead is a HypoT neccessity.

What test results did you get?

1 like

Had 3 tests since August, 180,226 then 206. Just watched that video, very enlightening!


hi be careful with your folate ,ask if you can have this checked i am taking b12 and my folate has halved in 2 months you should take both alongside each other B12awareness.org watch this please the hour video on you tube

1 like

Thank you guys, I took one today but will not take another unless I get an unsatisfactory response from haematologist. Just need to get well and back to work x


The ranges accepted in Europe, Japan, and the USA differ from the UK.

Anything less than 500 is considered less than optimal and supplements are prescribed whereas in the UK your levels will be considered normal with most doctors.


I know have B12 jabs after insisting on being referred to haematologist


You may also like...