Thyroid UK
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Carbimazole and weight gain

Hi there,

Just wondered, is it normal to gain weight on Carbimazole? Diagnosed HYPER 3 weeks ago T4 51, already gaining before diagnosis and 3 stone overweight... Desperately trying to lose weight, no sugar, caffeine, junk... But weight still gone up slightly :-(

Any suggestions? Is it impossible to lose weight on this drug?

Thank you

4 Replies

Hi wild poppy,

Yes, weight gain with Carbimazole is very common - I put on nearly 2st when I was taking it. However, I took the view that it was better to get my thyroid condition under control, and worry about the weight afterward.

It has come off albeit slowly, but worth being well!



Thanks Arab

2 stone! Omg, if I put that much on i'll be waddling? I am already overweight by almost 3 stone... Its been coming on slowly over 1-2 years (previously 9stone)... I know what you mean about being well though, I do desperately want to be well.

May I ask.... Were you strict with what you were eating at that time? Or just eating what you fancied. I am just wondering... I eat healthily, then eat rubbish afterwards.. ) although never enough for 2 stone I would've thought, as I exercise lots. So am just wondering about damage limitation, as in, if Iam strict with my food, would it help keep weight off... I REALLY cannot bear to put anymore on!! Have you had to diet to get it off or did it just come off naturally when you stopped the Carbimazole?

Do you know WHY Carbimazole does this? Or is it the thyroid adjusting?

Sorry so many questions, my fat clothes are no longer fat clothes!

Thank you Arab for answering :-)



I really sympathise with where you are at the moment, but be assured that most people do well on Carbimazole and you should be on the mend quite quickly

I simply think Carbimazole just shuts everything down in order to give the body a much needed rest, and to allow the massive amount of thyroid hormone racing around the body time to dissipate.

I tried to eat sensibly, but when you are hyperthyroid, you are naturally starving, and it's difficult to adjust afterwards.

I had to really concentrate on dieting when I became euthyroid. I hated the extra weight I was carrying, and I'm still 10lb over, although I have been having periods of hyperactivity over the last few months which has made it difficult to maintain.

However, it can be done.

Going gluten free helps to lower the antibodies - wish I'd done that sooner, and read up on the subject.

I got the Thyroid 12 blood test done with Blue Horizon, a recommended laboratory.

For myself, I make sure that I include Selenium 200mg daily and also Magnesium, B12 and D3 with K2. Also effervescent Vitamin C with Zinc. These seem to be the the core minerals and vitamins that we are low in with autoimmune diseases. You can find out more by asking others on here.

The side menu here on this site has Graves and also Hyperthyroidism, so you can check out what others have done and how they've coped.

I'm so glad I found TUK it's been a mine of information and the administrators are really helpful.

Good luck, and use this site frequently. It's the first port of call for me if I need advice.

Arab. 🙂


Thank you for the info on Blue Horizon :-) I am gluten free as I have celiac disease....And yes, I I am also low in B12 and D!! Thank you for all your wise words... I seem to be having rashes to the Carbimazole and am worried its dangerous :-(

I have a started another thread about it as, someone on here said to watch out for it...

Why is nothing plain sailing?!!

Thank you Arab :-)


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