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Thyroid UK
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Hi all,

I'm currently on 100mcg of Levo, only been on this dose for a around 6 weeks but feel lots better apart from feeling low about weight gain.

I recently asked GP if I could be tested for vit D amongst other things i thought i may as well be tested for ( b12 and ferratin etc) but she said that weight gain is unrelated to vit D (I've been hearing to the contrary) and that it should be left till I've been on 100mcg of Levo a bit longer, it's like she doesn't want to look at other possibilities yet.

My thoughts are that I may as well be tested for all the rest of the things when I go for my next bloods..in a few weeks. Any thoughts?

Clare x.

18 Replies

As I see it, whether or not weight gain is related to vitamin D, being tested is a perfectly reasonable thing to do.

I cannot see any reason to relate it to your thyroid treatment, etc. If your D is low, it is low and the issue should be addressed. Sooner rather than later.

(Certainly we all too often see D levels being low, and there seems to be some connection to thyroid. Quite why is rather less clear.)

B12 should be tested earlier rather than later because, if seriously low, the possible nerve damage is irreversible.

Iron/ferritin should be tested and treated asap because iron levels affect the ability to metabolise thyroid hormone properly.

I wouldn't go in there guns blazing, a few weeks probably are not really going to make much difference, but unless the GP thinks you are going to decide you do not want them, and therefore can save the costs, there seems little-to-no reason to defer the tests.



Hi what do you class seriously low b12 mine is 375.

Thanks x


That is at a level at which I would supplement.

Ideally, I think you would have an Active B12 test to determine where you are with more certainty than a standard serum B12 test.

Without better information, it is impossible to be sure.



Thanks Rod, I've already started supplements.


Hi, the range for the B12 I had done was about 250 - 950. My result was 635. To me this is still way off being at the optimum level and I am supplementing to get it up to around the 850-875.. GP's seem oblivious to the fact that B12 & Vit D are paramount to the working of the brain ---( why do most of us on thyroid meds have brain fog? as do many others of course) Ranges are necessary because they tell you how far away or how near you are to the optimum level. Of course optimum levels may well vary from person to person but the gap is NOT going to be that large.

It is proven that we no longer get all the essentials we need from the food we eat, so it is even more important that care is taken to ensure optimum levels.


Ricketts is being seen again in children, when it was considered to be consigned to history.

It is thought that the poor sunshine record of recent years, and sun-block use is contributing to the reappearance of the condition. Many adults are now considered to be Vit D depleted too. I started to take a Vit D supplement, as sunny days are a rarity here in north Scotland, and I feel much better.

So it should be tested for, whether or not it's linked to uat, and corrected if low.


Hi Rod,

Thanks for replying.

I'm definately going to ask for these tests for when I go back to check my t4 and TSH, it will give me piece of mind too as I will only wonder and keep wondering. Like when I was initially finally diagnosed as hypo..it pays to be persistent.

Clare x


Good - think that is right.

By the way, if you click on the blue "Reply to this" at the bottom of an answer, the person you are responding to gets an alert email. :-)



Hi. I am on the same level of Levo 100mcg and have been for the past 7 months plus Vitamin D supplement and I'm sorry to say not a pound has shifted. In fact My Weight has been about 15 stone for a few years when I first suspected their might be something wrong with me. No matter what I do my weight just doesn't seem to go down. I keep giving things up but no luck. I have increased excercise but guess it's just not enough.

On the bright side( if there is one) at least if there is a famine we under active thyroid people might survive.


You made me laugh this miserable day!

I am trying to lose weight it is very slow, browned off with it.

If only someone would come up with the answer to help us.

Until I became hypo 20 years ago I could keep my weight down when I tried, but since then boo hoo I can't. I know all the theory by now heaven knows.

Still, thanks for cheering me up a bit. Lol


I keep giving you the answer: optimise your thyroid hormones.

Diets and excercise will not make you lose weight if you are hypo - it's probably not even fat in the accepted sense of the term, but myxoedema. Diet won't help that.

What is more, low calorie diets and excessive exercise can make the problem worse by depriving you of precious calories that you need for convertion. Also exercise uses up your hormones - and you haven't got enough to begin with!

Without knowing all the details, it is impossible to say for sure - and I'm sure your doctors wouldn't agree with me - but what do they know! - I would say that if you can't lose weight, you need an increase in dose.

I'm on a dose of T3 now that makes strong endos faint. But it's only now that the weight is coming off. And all by itself. I eat what I want, when I want and how much I want. And I don't get much exercise. And no, I have absolutely no hyper symptoms. I'm just beginning, in fact, to feel what might be called vaguely 'normal'.

The problem is that doctors are so ignorant about hormones and so terrified of them that they dare not give a high enough dose for most people to lose weight. They need more education on the subject. But so do patients. Because by insisting on not ingesting enough calories, by cutting out fats, and by excessively exercising in the mistaken hope that a trip to the gym cures all, they are probably doing themselves more harm than good.

It is not your fault if you have put on weight, It has little to do with what or how much you eat. it is because your thyroid is not working correctly. Therefore the way to reverse the situation is to make sure you get enough replacement thyroid hormone. I know that can be a problem, but that is the way to do it. Your doctor will probably disagree. But a word to the wise: never take advice on nutrition or weight loss from a doctor unless he has specialised in this subject (and even then...). They do nothing of that sort in med school, they know no more than the man on the Clapham omnibus!

Good luck to you all, Grey


Hi Greygoose,

Are you taking Levothyroxine with T3? I am on 125mg Levo, but cannot lose any weight, even by fasting for a couple of days as one diet recommends, makes not difference to me. I have purchased some T3 from abroad (naughty) but I am a bit confused about what dosage to take. I have 25mgs T3 so I reduced my Levo to 25mgs also, as I was told T3 is 4 times the strength of Levo. However I started to feel unwell (dizzy, off balance and extremely tired). Can you give me any suggestions or help? Many thanksx


No, I don't take any levo. I would say you reduced your levo too much. Personally, I would have reduced by 25 mcg to begin with and waited to see how I felt. All this business about T3 being four times the strength of T4 is a bit of a red herring, in my opinion, because if you don't convert very well, T4 has no strength at all! However, you must have been converting some - impossible to know how much - or you wouldn't have noticed such a difference. You've just taken a huge drop in dose so not surprising you feel bad! When did you make the change? If it was some time ago, best to put it back up slowly.

But you are still only on a pretty small dose. And certainly 25 mcg levo and 25 mcg T3 is not going to make you lose weight. Nor, I fear is fasting. Fasting is for people with healthy hormones. What do you do for calories during those two days? How do you convert your T4 to T3 if you haven't got any calories? Never mind all the other bodily functions you have to support and the activities you try to do. I really, really don't think that's a good idea. Leave that sort of thing until you have worked up to higher doses.

Hugs, Grey


Thanks for your reply, it is good to know these things.

I take levothyroxine, and I have noticed I need more in winter than summer. Let's hope things look up. Lol



You should definitely get tested for vit D/B12 and all the other bits, don't know how they can call it a full blood test when they don't routinely include these, especially as b12/vit d/low iron etc often run alongside UAT. After thinking my thyroid tablets needed upping cos I was soooo exhausted and couldn't lose weight (in fact, although I was already 4 1/2 stone overweight I put on another stone in a matter of a couple of months) I was tested and found to be B12 def (October) recently after feeling I was only getting the benefit of the jabs for a couple of days I started supplementing, I'm taking Jarrow Methyl B12 lozenges 5000 (started on 1000) and have noticed that since upping the dose that I am losing weight, still got a long way to go but I have lost 6lb in two weeks, apparently you need your B12 levels to be at optimum levels in order to lose weight, just hope it keep going in the right direction


Hi Val

I just ordered some B12 from amazon, I will try anything !

Best wishes


I am going to see an endo next week.Currently take Armour.

I have only ever been tested by the GP for T4,TSH, & T3(at my request).

from reading the comments look's like Vit D, Vit B12, and iron should also be tested too, are they any other tests I should request. Rather worried about stomach bloating too?

Thanks to all, learning so much from this site, no longer feel on solo crusade for health!!


Thanx everyone, can't seem to reply to specific comments just now.

Katelou...vit D, B12 , iron and ferratin are the ones I know off, Only my THS and T4 have been checked out thus far but I'll ask for T3 again.


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