Do I need to change my dose of T4?: I have been... - Thyroid UK

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Do I need to change my dose of T4?


I have been taking 75mcg of T4 and 20mcg of T3 since January. I generally feel better but my endo who has discharged me back into the care of my GP felt that if my T4 remained low ( last test it was 0.11) then my dose of T4 should be reduced to 62.5mcg.

My recent blood test was TSH 0.05 serum free T4 10pmol/L (9-25) serum free triiodothyroine 4.3 pmol/L (3.5-6.5)

What do you guys think I should do?

I still feel my T4 level could be higher, but will taking T4 increase this?

Thanks in advace Nicola xx

10 Replies

nicola, your free T3 is very low at 4.3. It's really the most important of your tests when it comes to how you feel so I would think he would increase your T3 rather than cutting your T4 (unless he would do both). Your T4 result is not all that important, especially when you are taking T3. Take a look at the recommendations here:

nicola101 in reply to Heloise

Hi Heloise,

I will not be getting any increase in T3 as I have been discharged back into the care of my GP. He did say that my TSH was too low and reducing the T4 would help to increase this a little. I have to say that I have been feeling better than I have in a long time so any change to my medication worries me. I am considering taking B12 and iron again as had stopped these and have only been taking Vit D. Thank you for you advice.

Nicola x


If you take T3 your T4 will be lower and I agree with Heloise re increasing T3 and maybe reducing T4. T3 is the active hormone and T4 (inactive)should convert to enough T3 but sometimes it doesn't convert enough.

Can I ask if all the main 5 are all well above the NHS lower ranges - iron, ferritin, folates, B12 and VitD - as if any of these are low (which would still mean above the NHS lower range) then you may not be converting your T4 or up taking your T3.

Please have a read of this link and see if it rings any bells with you. especially the bit on iron/ferritin.

Moggie x

nicola101 in reply to Moggie

Hi Moggie,

I have had B12 tested July 2012 and this was 308ng/L (low) but GP refused to give B12 injections. I did try to take tablets but found I reacted with facial flushing so stopped these. Ferritin level 19ug/L (low). Did start to take iron tablets but not had these checked since last year as GP says all normal so no need to check again. I take Vit D as this was 50nmol/L so again low.

Do you think I should try B12 and iron tabs again and if so whick B12 would you suggest?

I have been discharged back into the care of my GP so there will be no increase in T3 as this was only given by Endo as GP refused to let me trial them.

Nicola x

tegz in reply to nicola101

Everyone is extolling the virtues of Methylcolbamin B12 which you can buy on line, either as sublingual -tabs or spray.

Not cheap- but reported from Holland to be as effective as jabs.

Not a way to treat severe B12 deficiency, but safe- if you can't get listened to and can at least get blood tests to monitor progress.

I use both -and am aiming for 500+ blood level, eventually as this is preferred level ,esp. if older. I'm demi veg,also.

Needed for Thyroid and general health.

Iron the same- Spatone has been spoken well of and easy to take, but I think this may be more important when on T4- for conversion.Check the T3 connection- as that's a lot stronger.

[PS: Did you fail on B12 Cyanocolbamin version? ]

Hidden in reply to nicola101

Can I just say that if the B vitamins you were on before contained niacin, you could have been experiencing "niacin flush":

If it was just a B12 sublingual, then I don't know why you would flush with that.


Moggie in reply to nicola101

Yes you should definitely try taking B12 and iron again as both of these a really important when taking thyroid medication. Unless your B12 is above 500, but preferably nearer 700, and your ferritin levels are above 70, but preferably nearer 90, then you thyroid meds may not be being utilised by your body properly.

You may also want to look at gut issues like coeliac as, being that so many of your vitamins are low, you could have something going on in your gut, which will not be helping your thyroid condition.

Moggie x

tegz in reply to Moggie

It really is cruel that Drs push out T4 in chunks without clearing the way forward for it to be utilised by the patient.

I look forward to the day when B12, D3, Iron & Selenium, at the very minimum, are brought up to optimal during T4 treatment.

Otherwise,the body just shovels it around -and I suspect RT3 kicks in to block unused hormones causing trouble in unbalanced systems.

RT3 tests may be relatively costly but the money wasted on institutionlised illness, badly treated ,must be huge.Spend it on something useful, like this.

We're always being nagged about healtrh choices we make by 'the system' -but why can't the 'pros' get their act together?

They get paid enough. Rant over :)

At least the OP here is getting T3!

Moggie in reply to tegz

I was seriously thinking of putting something similar into the "suggestion box" at my GP's - asking for B12, VitD, iron, Ferritin and folates be tested as soon as a patient is found to have thyroid illness. Don't think we will EVER get the GP's to admit that our levels of the above need to be at the higher end of the NHS ranges for our thyroid meds to work properly, god forbid that they try and sort issues out BEFORE it has cost them a fortune in unnecessary treatments when thyroid patients get no better on their inadequate treatments and care.

Moggie x

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