Thyroid UK


I am about to undergo knee surgery, in a week. Pre-op bloods showed that my thyroid level was slightly low. I don't know the exact reading and hopefully I t won't stop the surgery when I meet the anaesthetist.

I can only tolerate levothyroxine 25mg daily but I have been fairly well since I added liiothyronine 25mg daily. I have always informed the Gp but am not sure he understands much. He just smiles benignly and encourages the thyroxine.

Do I understand that taking the T3 suppresses the TSH.  I think I need to know a bit when I meet the anaesthetist. I have been waiting ages for this op and don't want to miss out now.

Please let me have your ideas. 

7 Replies


It would be helpful to know what your results are?

25mcg Levothyroxine and 25mcg T3 can suppress TSH.

The higher proportion of T3 to Levothyroxine probably also means that FT4 is low which isn't a problem if FT3 is good.

I hope your operation goes ahead and is successful.


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.


Thank you for your speedy reply. I failed to get the printout as I was at the hospital for the result. my GP says he can't request a full thyroid profile: it is TSH or nothing. So I work on symptoms alone and have felt so much better since being on T3 with a low dose levothyroxine to keep the GP sweet. I have wondered about raising the T3 dose as I have been on it for over 6. Months, but am a bit worried about doing it.

I am so glad for this site. Thank you for your good wishes. And your input.

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Hi, I had a knee replacement last year, I told the anaesthetist  I was on NDT and I have a low tsh , I didn't have any problems.  Good luck!


ThAnkyou for that. I needed a bit of reassurance.

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Hi I was reading your reply and noticed that you said that you were taking NDT. I recently sent to America for this as I have been on thyroxine for 18 years and although I'm not as unwell as a lot of people on here I do have weight gain 3 stone high cholesterol, insomnia and fatigue. I have eventually talked my GP into doing a T3 test 😀 As I defiantly don't think I'm converting T3.  I have been trying to loose weight as I'm going for surgery soon and was told I'm over weight when I went for my pre op !! I decided to send away for NTD as I'm at my wits end as I keep weighing myself and in the space of 5 weeks haven't even lost a pound, regardless of cutting out a lot of carbs. How have you found the NTD has it addressed your symptoms 


Hi carribaby, I put 3 stone on in a few months after a hysterectomy, I now realise I was hypothyroid , no treatment , my main problem apart from the weight was sleeping, I had to nap every 2 hours in the day, no energy etc.  I had a goitre when an ENT consultant spotted it, I had a TT and was put on thyroxine, no matter how much my GP increased my thyroxine I still felt ill.  I obviously wasn't converting. I joined this forum added some T3 to my thyroxine and felt better instantly. I have tried various combinations of meds and now settled on 3 Grains of Nature Throid, best I have felt in almost 20 years.

It is so annoying when consultants mention weight, I get very defensive  and explain I wouldn't have weight gain if I was  on right meds.   I have lost a few pounds, but I have low sugar so I tend to eat a lot of carbs.  

 I am sure you will feel a lot better when you start taking your NDT.

Good luck, Best wishes Bev.

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By 'thyroid level' I take it you mean TSH - which is a pituitary hormone, not a thyroid hormone. A low TSH is not a problem, I think your anaesthetist would be more concerned if it were high. And taking any form of T3 will make your TSH low. It means nothing  much.

But, to set your mind at rest - and to reassure the anaesthetist, why Don't you get a private FT3 test. If it's not over-range, no problem. :)


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