Thyroid UK
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Thyroxine reduced dramatically quickley

I have taken thyroxine for 10 years or so and was merrily taking 200mg and was really well. Bloods were T4 15.9 TSH 2.7

Starting in August bloods showed T4 27.8 and TSH less than 0.05 ??

Dr starting to reduce thyroxine with 8 weekly retests 175,150 and now 125 TSH still less than 0.05 didn't get T4 result last test.

Feel really well but wondered if anyone else had experience of this Dr doesn't seem to know why ??

14 Replies

I have a query. You posted:-

T4 27.8 and T4 less than 0.05

Do you mean a TSH less than 0.05?


Ooops sorry have amended it to read correctly Thank you for your help. :-)


Can I ask if you changed levo brands around the same time?

Moggie x


No Moggie Brand just the same x


Hi Cazzie

I am not sure I can be much help, except to say that after 10 years or so balanced on 100 mcg levothyroxine, I too became overmedicated. My annual tests used to average around TSH = 1.5 or 1.6 (0.2 to 5) and FT4 about 19 (9 to 21). Last year my results were TSH <0.05 and FT4 = 24.3 (same ranges). My dosage was reduced and it did have the desired effect of bringing the blood tests into the reference range. Over the past year, I have bounced up and down a bit and have varied in medication between 100/75 mcg on alternate days and just 75mcg. I recently had another 'hyper' episode when on the 100/75 mcg combination so just on 75mcg at the moment.

You don't mention how you are feeling? Did you have any of the overmedication symptoms as listed on the patient information leaflet? Have you felt any different as your dose has reduced? I experienced over-medication symptoms as per leaflet and a few other things besides!

Have you been doing anything different? Moggie asked about levo brands. There has been a lot of discussion about Mercury Pharma 25 mcg on this forum. I am still trying to work out by trial and error if they are contributing to my 'ups and downs'. Prior to the change in my blood results last year I retired, became much more active and lost weight - so age and less of me may have contributed to needing less levo.

Sorry, I can't help on why TSH remains low after reducing levo by quite a bit. Others on the forum would advise to get FreeT3 tested too, plus vitB12, folate, ferritin, iron, calcium, vitD - all of which affect absorption and conversion of T4.

Hopefully others that understand the T3 side of things better than me will have some suggestion.

Liz xx


Thanks Liz Just hearing from you that you have had ups and downs helps as I had only ever experienced medication being increased.. I too retired but 3 years ago and I have lost some weight so maybe that's a factor. I feel fine and had no overmedication symptoms.

I haven't been doing anything different and feel no different with the reduced dose. Very strange !! x


Hi Liz

Went back for latest results yesterday and TSH now 0.08 so at least something is happening with reduced meds. They didn't do T4 level again Dr said not necessary ? Thyroxine reduced again to 100mg daily so now on exactly half the dose I was on.

I've also been thinking about your reply and the bit about absorption being affected by vitamins and calcium. Before I went through the menopause and was working full time I took calcium, vit tabs and evening primrose oil (never at same time as meds) but since being retired and having more time to eat a healthier diet I've stopped taking them all. You may have hit the nail right on the head but whatever the reason the good thing is I feel well. Again thanks for your reply Liz it was a great help.

Carol x


Hi Carol, thanks for the update and it is good you are feeling OK again.

I am a bit surprised that your doctor said T4 test isn't necessary. Clinical biochemists guidelines actually say that if TSH is out of range FT4 should be done, and if TSH is persistently low both FT4 and FT3 should be done; at 0.08 you are probably below the reference range, though you do need your labs reference range to be sure. Your practice should be able to give you them as they come with the results. The labs in my health area seem to give both TSH and FT4 all the time and I am just used to comparing them both! Maybe next time you should ask for FT4. If it has dropped but TSH remains really low, it could indicate other things are going on.

I had all the vit and iron etc tests done and am well up the ranges without supplementing (except calcium and vit D, but that is because of parathyroid issues), so agree that for me a healthy, varied diet seems to work too, though I know that isn't the case for everyone.

However, the main thing is that you are feeling well (as my GP likes to tell me!)

Take care, Liz.


Thanks Liz

I usually get both results but not for my last 2 tests. I'll be having another in 4 or 5 weeks and will ask nurse to specify both results.

You have been a huge help and I feel much better about the situation.

Hope you continue to keep feeling well.

Kindest Regards

Carol x


I would definitely question the maker of your T4. Unless you have done something drastic as the one poster said who lost weight and became more active AND retired which may have reduced stress. I've known and only heard of one hypOthyroid person whose gland began functioning fully but it wasn't after ten years. This is really unusual I think. Do let us know if you find the answer. Would they do an ultrasound to see if there are any physical changes?


That's why I posted I thought it seemed strange I will ask GP about ultrasound but I've never had one so there would be no comparison. Thanks Heloise x


Ooops, I should have said I had a total Thyroidectomy, so no chance of it kicking in! Liz.


My remarks were directed more to Cazzie's post, tin. But, like you and maybe I'm a lot older than you are, I couldn't handle any more than 100 or in my case the equivalent, one grain of Armour. My TSH is also 1.6 but I did not feel well. I decided to go on T3 only and can raise it without feeling hyper now. If you start feeling badly, you might consider it.


Thanks, Heloise. I guess I was pretty fortunate sailing along for so long on levo with no problems. Juggling dosages and more frequent than annual blood tests are new to me. Feeling OK at moment, so not even raised issue of T3 with GP!!!


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