Thyroid UK
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Weight gain after thyroidectomy, please help!

I had a partial thyroidectomy in November, cancer was found so I had the rest of the thyroid removed 4 weeks later. Was on 150mcg but it was upped to 175 at the beginning of Feb. I still feel absolutely shattered all the time, I have gained weight which is really depressing & could just shut myself away & sleep if I could! Some people (including a GP) said that you'll lose weight on thyroxine but I've gained it not lost it!! I had a blood test this week & am seeing my GP this week & my consultant at the beginning if May. Any advise would be greatly appreciated though! Thank you!

7 Replies

What they neglect to say is that you'll lose weight if you are on enough thyroxine! It's not the thyroxine itself that is making you put on weight, it's the deficiency in thyroid hormones.

Make sure you get a copy of your blood test results (you have a legal right to them). Then you could post them on here (with the ranges) and people will be able to comment further.

Sorry to hear you're feeling so bad. I do know exactly how you feel, but it will get better once you're on the correct dose.

Hugs, Grey


Hi mum21 - sorry to hear this :( When you get hold of your blood test results, please can you post them on here and people will be better able to advise. Your weight gain and other symptoms would indicate that you are probably under treated and need an increase in thyroxine, but we will be able to tell more when we see your actual results. Xxx


Thanks, I'll ask for them & post them once I've got them!


Great :) xx


This is a link and read the first question/answer. Weight gain is a very, very common question.

and this is the link within that answer


Hi. I had a thyroidectomy too and so far, have not gained weight, but I think that's because my GP is working hard to get me on my correct dose of levothyroxine. I know exactly what my thyroid levels all were before the operation, and she is aiming to get me as near as possible to that again. I suppose I was lucky in a way that I was monitored pre op for ten years. Do you have any results from before the op? Then you would know what to aim for, although i did read somewhere that for cancer sufferers, its best to have a supressed tsh. Also, it may be that your body is not absorbing it or also possibly if you had to come off the medication for RAI.

Good luck


Hi Some thyroid is always left behind so normally the thyroid is treated irrespective of surgery, how it is at this time. However, make sure you are under a really good endo. Depends how you feel ( obviously rotten) and TSH, T4 and Free T3. You may also need some T3. Also endo will do the other essential tests which often go with thyroid. Even if you had them in the past, they need repeating. Glucose, if pos. also Hb!1Ac ( diabetes), hormonal and autoimmune, vit d,( hormonal)if low corrected calcium before treatment, iron/ferritin and B12 and foliates, autoimmune. All really important. make sure the endo good first before asking for a referral.

Best wishes,



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