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Thyroid UK
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Weight Gain!

Hi everyone!

I've been seeing an endo since last Oct, initially in the hope they would let me have T3, but no! Then I was given the option of carry on self treat with T4 or T3 or combo or work with the endo to get me on a dose of just T4, so I thought ok, it's took years to get to see an endo, so let's go for it!

I was on 175 T4 and started with a gradual lowering until now I am on 125 for 2 days, then 150 for 1 day and back to 125 for 2 days and then 150 etc. I have been on this dose now for a couple of months. Meant to have another blood test next week to see where my TSH is etc.

So, while I guess I feel ok, but tired some days etc, my problem really is, I have gained a almost a stone in weight since last Oct and since starting to lower the T4! And I train hard and have a reasonably healthy diet! But nothing I do = weight loss! In fact it almost seems the harder I train, I have gained a pound or two at the end of that week!

I discussed this with the endo and he said I looked fine, why am I worrying, well thanks Mr Endo but I know I should be carrying much less that the current 30+% body fat than I am currently carrying! Anyway, he said if I carried on with my healthy lifestyle, my metabolism would catch up with itself.

Has anyone got any ideas on this? Oh and I had my T3 checked at the last blood test and it was 5.20 or 5.30, so that seems good to me. Any ideas on what has worked for you in the weight loss department? And has anyone else gone along with an endo and reduced meds only to gain weight like this and struggled to lose it? Never thought I'd turn into my sister, who struggles to lose weight and doesn't even have a thyroid problem!


16 Replies

Do you have a range for that FT3? The number on it's own means nothing. It looks sort of mid-rangeish, but if you are training hard, you need it higher than that.

Every movement you make uses up a certain amount of T3. So, it's pretty obvious that rigorous training is going to use up all your T3, and leave you more hypo. Which, as you have found, makes you put on more weight! Your body cannot easily replace the T3 your using, as it used to when your gland was healthy. Plus, you might not even be converting very well.

Sounds like your endo is a special sort of idiot, if he doesn't even know that! And he's absolutely wrong about your body catching up with itself - what does that even mean?!? And why is he reducing your dose? Why? Because that's what endos do! If I were you, I think I'd go back to self-treating with the T3. Sounds as if you were making a better job of it than this endo person. It's a mistake to think that just because he's an endo, he knows what he's doing. Most of them have no idea!!!


Thanks greygoose! Yeah, range is 3.50 - 6.50

FT4 was 25.8 range 11.00 - 23.00

TSH <0.05

Also had B12, folate, ferritin, magnesium and everything else tested and all are well in the normal range!


OK, so I was right, the FT3 is just over mid-range. Most people need it up the top of the range to feel well.

And you're not converting at all well. Your FT4 is well over range just to get your FT3 to mid-range. So, that's not good. You've got a lot of unconverted T4 sloshing about there. You therefore do need your T4 reduced, but you also need some T3 added. You can't do it on T4 alone. Idiot endo!

'Well within the range', tells me nothing. Do you have the numbers for those nutrient tests? As we always say 'in range' is not the same as optimal. To be optimal, B12 needs to be about 1000, which is over the top of most ranges. Vit D, ferritin, folate need to be at least mid-range. Absolutely no point in testing magnesium, that will always be in range because of the way the body handles magnesium. But that doesn't mean your aren't deficient. Most people are, and being hypo will make it worse. I would just take magnesium, anyway. The body excretes excess, but it's not good to be deficient. So, if you have the results of those tests, I would post them here, if I were you. :)

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Greygoose, I forgot to ask, but I seemed to have what can only be described as roid rage when I was trying to take T3 with T4 last time, but I was on a higher dose of T4, so could that have been caused this issue...? 😳


I suppose it could have. But, in my opinion, more likely to be the low T3. I got that when my dose was 'accidentally' reduced by 100 mcg once.


Wow! Thanks again greygoose! Interesting indeed!

Ok, so:

Magnesium 0.87 range 0.70 - 1.00

Calcium 2.41 range 2.10 - 2.60

Ferritin 189 range 20.00 - 250.00

Serum B12 611 range 190 - 900.00

Serum Folate 9 range 2.00 - 19.00


Vitamin D result?

Your folate and B12 should both be higher so you need to supplement.


Thanks bluebug!

Vit D was 90.8 but don't have the ref rang for that one...


At the moment you don't need to supplement D unless you are supplementing already. However you do need to get out in the sun regularly this summer. Make sure you don't burn.

Also until you get your thyroid hormone levels sorted out train less frequently.


Thanks bluebug! Yeah, I do sit I the sun when I can and have taylored my training to be slightly less, but that's hard for me as I do love a good workout!


I agree with bluebug, but I would go even further, and say cut out the training until you get your T3 up higher. At your present rate of training, taking T3 will be like trying to fill a bucket with a hole in it. As fast as you put it in, it will fall out the bottom, so necessary repairs to your body will never be done. You will not heal. You should just be doing gentle walking. Actually, with a T3 that low, I would be comatose, but that's just me. :)

So, personally, I would take 1000 mcg sublingual methylcobalamin daily, to bring your B12 up to optimal. And take a B complex with it to balance the Bs. If you get one with methylfolate - Thorne do a good one - that will bring your folate up. You can find everything you need on Amazon. Myself, I would never dream of buying vits or mins in a supermarket or health food shop, because the quality is often just not good enough.

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Thanks again greygoose! I would also add T3 To the T4 but it will affect my blood test results won't it and the endo has told me to leave off the T3 until my TSH is in range! Well, says I don't need it at al! But I am so in despair with this fat/weight gain that I am almost becoming desperate! Should I add some in your opinion to bring up my T3? Will deffo get the methylcobalamin and methyfolate! Thanks for the advice!


Of course it will affect the blood tests, that's what it's supposed to do.

So your endo is lowering your dose to raise your TSH??? Moron! You really should leave this man as fast as you can. He is going to make you ill.

You need that FT3 raising, and to hell with the TSH. If you are properly treated, you don't need the TSH. And if he's obsessed with the TSH, that means you will never get your T3 because it will more than likely suppress your TSH and what will he do then? He'll stop your T3.

You are at risk for so many other things, like heart disease, if you stay hypo. Let your endo go and experiment on someone else. Take back the control and start the T3 again.


Thanks greygoose! You are a star! I'm glad I asked the question now!


You're welcome. :)

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Oh gosh this sounds like me - so less training? I am too confused! This sucks!

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