Thyroid UK
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I was wondering if I could get advice as to what to do next.

I take 20mcg T3 first thing in the morning and T4 early evening 75mcg.

I have Hashis and also take gabapentin for burning mouth which I believe is associated with Hashis but that is another story !!

I am feeling exhausted, no motivation, emotional, dizzy and brain fog is driving me crazy.

Recent test- TSH 0.05

FT3 3.8pmol/L

FT4 11pmol/L

I haven't had other levels tested for over a year. My GP hasn't really got a clue and is happy to test cortisol levels, Vit D, B12, calcium etc and these will be done soon.

I feel I may need more T3 and if so will have to source myself as I have been discharged from the endocrinologist who started me on T3

I kept a record of my temperature,blood pressure and heart rate recently.

on waking temp was 35.6

Blood pressure 100 69 and heart rate 65

half an hour after taking T3

temp was 36.3

BP 105 55 and heart rate 65

2 hours after T3

temp was 36.1

BP 115 76 and heart rate 60

I would be grateful for any advice as really don't know what to do next.

Thank you in advance

11 Replies

Nicola, after you find out your B12 results, post them here.


I will do. I know last time it was checked it was low but not low enough for

G P to do anything.


Low B12 can cause burning tongue.

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It has to be practically non-existant for a GP to do anything because they Don't understand the importance of B12. So, if it's Under 500, you have to supplement yourself, because anything Under 500 can cause irrepairable neurological damage. But doctors Don't know that!

Your T3 looks very low. Do you have the ranges for those results? Seems to me you need an increase in your dose of T3. Why do you take one in the morning and one at night? Why not take both T4 and T3 at night?


Thank you for your reply. I take T3 and T4 separate as thought we had too. I used to take all in morning. The ranges for Ft3 are 3.5~6.5 and my level was 3.8. I believe last time my B12 was tested it was well under 500. I have been taking B12 but stopped as thought needed other B vitamins too.


There's no reason why you shouldn't take T4 and T3 together - you would if you were on NDT. But you definately need an increase in T3, that's much too low.

You do need other B vitamins, too. So, when you're taking B12, you take a B complex at the same time - preferably one with methylfolate. If your B12 is Under 500, I would urge to start supplementing again pretty soon.

So, there you have two reasons for your not feeling well. Up the T3 and go back to the B12, and you should start feeling better. :)


Thank you for the messages. Do I need to leave some time before taking B12 and T3/T4 and can I take Vit D with these too? 😊


You should leave 2 hours between taking your T3/T4 and taking your B12, B complex and vit D. It's best to take vitamins with food, so why not take them with lunch? :)


B12 needs to be at a good level in order for the thyroid meds to be used by the body. So I'm guessing yours may be too low. I'd had underactive thyroid for fourteen years before my low B12 was picked up. A lot of the symptoms are similar to thyroid ones. Good luck with getting your B12 test results, you need ferritin, folate and VitD to be tested too. MariLiz

1 like

Have now got some results from the GP

Vit D 71

B12 852

Serum iron 13

ferritin level 66

FT4 9

FT3 4.8

My FT3 has gone up and FT4 has gone down since my last results in August.

I have increased my T3 to 45mcg a day and am taking 75mcg T4.

Since increasing my T3 there has been an improvement in energy levels. Split the dose into 32.5 first thing then 12.5 mid morning.

The GP said my iron levels were low so could buy some over the counter iron or eat more leafy veg !!

Any advice welcome, thank you :)



B12 825 is good but maybe due to you supplementing if you were taking B12 within the last 3-4 months. If so, I would continue supplementing B12 with a B Complex vitamin to keep the other B vits balanced.

Supplement Ferrous Fumarate for the iron/ferritin and take each tablet with 500-1,000mg vitamin C to aid absorption and minimise constipation. Take iron 4 hours away from Levothyroxine.

VitD 71 is almost in the replete 75-200 range but a maintenance dose of D3 2,500iu is usually needed Oct-Apr when ultraviolet light is too low to stimulate vitD. VitD should also be taken 4 hours away from Levothyroxine.

FT4 is low because you are taking a lot of T3 with Levothyroxine. FT3 4.8 is good in range 3.5-6.5 and gives you room for a dose increase if you need it.


I am not a medical professional and this information is not intended to be a substitute for medical guidance from your own doctor. Please check with your personal physician before applying any of these suggestions.


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