Thyroid UK
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Does anyone ever loose weight once on thyroxine?

I've been on 100 mg thyroxine for 8 weeks and am not seeing any positive impact on weight. During this time have gone mostly gluten free, taking selenium, sea kelp and drinking chlorophyll all to try and help. It's really getting me down as I feel like no mater how little I eat my body keeps recalibrating going to keep me at the same weight. I have a young baby (9minths) who often is awake during the night and am trying so hard to loose weight even on very little sleep and nothing is working. I need to loose a stone and a half and it just won't budge.

My reading was 8 when I started my medication and that had gone up from 5.5 in a year. I feel better and my skin is better but still not 100 % I don't think. But the lack of sleep doesn't help me really get an accurate picture of anything!!

I am just desperate to shift this weight. Has anyone actually lost weight once their medication was right? Need some advice and inspiration? Does the blood sugar diet work? Going to try that next but I know the 800 cals a day will be tough with little sleep and a young baby to chase around!!

9 Replies

Apologies for typo... lose not loose!


Levothyroxine isn't a weight loss hormone. I do know that weight gain is the most common question and is distressful to many.

As your levothyroxine is gradually increased until your TSH is 1 or lower (some doctors think anywhere in the range is fine) you should then find that your weight will diminish - sometimes with a diet. At present if you are eating little, that's not too good an idea. First hypothyroidism means that our metabolism has slowed so much and small increases in levothyroxine to get to an optimum dose. That means a dose in which we feel well and energetic and we aren't exhuasted doing housework etc. You also have a new baby to care for which will take a lot of energy that you don't yet have.

Forget about weight at present - eat well as we need good nutrition for energy - concentrate on your baby as this is a very important time and with Mum not feeling too good it is an extra burden for you.

You might find if you take your temperature and pulse that both will be lower than normal and that's what replacement hormones do, raise our metabolism and temp and pulse come back to normal and you feel energetic.

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Many years ago I did lose 5 stone whilst on Thyroxine, however I had to be drastic in that I had six weeks on 500 calories a day and certainly would never recommend that !

Once kick starter I lost the rest with WW but after two years fell off the regime and gained back the weight Plus +

Hope you find a way for you.

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Hello there,

I put on a good 1.1/2 stone as I was eating like a woman possessed! As soon as I finished my meal I was foraging for biscuits nuts anything . I wasn't until my son said Mum what's going on ?

After being told I was hypo I bought a book on thyroid diet & it says load up on full fat everything , but to be honest i wasn't enjoying that.

I'm now with slimming world & ive lost 9lbs in a month .

Also as tired as I feel I force myself to walk hard for half hour twice a day weather permitting. So give it a go ! I still feel all the thyroid symptoms are at me daily . But it does help, lots of protein,veg & friuts!

Good luck 😉

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First of all, I have to say that 8 weeks is nothing in hypo terms - a mere blink of the eye. It can take years to get on the right dose of the right thyroid hormone replacement for you - especially if you're dealing with ignorant, pig-headed doctors!

It all depends how well you convert that T4 (levo) to T3. Levo is just a storage hormone, does little on its own. It has to be converted to the active hormone, T3. If you don't convert well, doesn't matter how much T4 you take, nothing is going to change. And, unless we actually test the FT4 and FT3 at the same time, we're never going to know how well we convert.

I couldn't convert much at all, but ignorant doctors had no idea! Even though here, in France, they will test both the Frees, the doctors didn't know how to interpret the results. And just kept increasing the levo, and I just kept on putting on weight. It was even worse on NDT! I ended up a bed-bound whale! But, through my own experiments, I found out I needed T3 only. And, then I lost the weight! It just fell off.

It's not just the fact of taking levo that is going to make you lose weight, it's whether or not it suits you, and taking enough of it - how much are you taking at the moment? After 8 weeks, I doubt it's enough yet. You don't get to your optimal dose in just 8 weeks!

'Mostly' gluten-free isn't good enough, it has to be 100%. There's no guarantee it's going to help you, anyway. Gluten in itself isn't evil, it's how your body reacts to it. And if your body has no reaction to it, cutting it out isn't going to change anything.

Taking selenium will lower your antibodies, if you have Hashi's, and will help with conversion. But probably won't have any effect on your weight.

Taking sea kelp, on the other hand, could be making things ten times worse - especially if you have Hashi's. Did you test deficient for iodine? If not, you're playing Russian roulette, taking iodine. Iodine is not some magic substance that is going to perform a miracle in your thyroid gland. It's a trace mineral - TRACE mineral - which means you don't want too much of it. Too much is as bad as not enough. So, you'd be better off getting tested before taking anymore.

Drinking chlorophyll? I've never heard of that. What's that supposed to do?

You see, if your weight gain is caused by low thyroid, the only thing that is going to make you lose it, is raising your thyroid hormone levels. T3, to be precise. Not taking iodine or chlorophyll, not even exercising and dieting. In fact, exercising and dieting will probably make you worse! Exercising uses up your T3, making you more hypo; and dieting - low calorie (800 a day? you must be mad! :P ) will have a negative effect on your conversion, making you more hypo. Result : you put on more weight.

And what about your vit D, vit B12, folate and ferritin? Have you had those tested? Your body is not going to be able to use the hormone you're giving it unless your nutrients are all optimal. Which is another reason not to go on a low-calorie diet, because your nutrient levels will drop even further.

So, patience is the thing. And proper testing - although, at just 8 weeks your TSH is still likely to be quite high, so you know your FT3 is going to be low, not much point in testing for it yet. But, do ask your doctor to test your nutrients. That's the best thing you can do for yourself, at the moment - that and nourishing your body correctly! :)


This is fantastic advice. Thank you so much. Sometimes knowing a little about something can be more dangerous than knowing a lot!

Sorry you have had a tough time with your diagnosis and treatment, you are clearly an expert now and I'm pleased you are managing it as best as possible.

I really appreciate your advice, it's so difficult to get your head round what you should do for the best. I don't have a lot of paitience and I like to get things done but seems I'll just have to wait this one out.

I stopped the sea kelp today. I heard about the chlorphyll on a you tube film from a lady that claimed to have cured her hypothyroidism with natural methods. Seemed genuine and had a huge number of views. It's a natural substance and I felt more hydrated and energised after drinking so felt right too. Hope there's no harm in that either.

Thanks again so much. And all the best.


I don't think drinking chlorophyll will do any harm, but I'd never heard of anyone doing that before.

Be very wary of anyone that claims to have 'cured' their hypo by 'natural methods'. In my experience, they're pretty soon back on the levo. I'm not saying the people aren't genuine, but they're usually deluded. They honestLy believe tthey've cured it. But, in my experience, they never have.

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Ps I am also stopping the dieting and eating proper meals now too. Your advice makes a great deal of sense

Going to ask to have my nutrients tested as well

Thanks again


Yes 3 1/2 stone but it's not all down to thyroid tablets true you have to get the meds right first once you have done that it's down to you I started yoga got my head in the right place then got the thyroid under control needed my head in the right place t do battle with the endo then went to Slimming World and lost 3 1/2 stone in a year that was 4 years ago and am still maintaining but its a work in progress. Good luck you can do it!

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