Thyroid UK
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Can Levothyroxine make you gain weight?

I'm on 125mg of Levothyroxine, and have been for about 9 years, prior to this I suffered extreme tiredness and disproportionate weight gain.

For a while now I've suspected that taking thyroxine has made absolutely no difference to how I feel, I am due my yearly check on Thursday, so as an experiment I haven't taken my Levothyroxine for 2 weeks. I feel absolutely no different, with the exception that I've actually lost about 5lbs, something that, even with effort, would take at least 6 weeks for me to do. So can Levo actually make you gain weight? And if it doesn't make me feel any better is there any point to taking it?

13 Replies

Hi there you sound exactly like me we could be twins ;)

I would love to see some replies.

Im at my doctors tomoro im going to ask him the same.

But i must say i dont find doctors very sympathic .

Let you know how i get on .

Take care vixx


Yes, to be honest I feel like a hypochondriac most of the time I visit my GP(s)! But I see little point in taking medication that doesn't seem to actually medicate anything! :/

I am also prescribed Vitamin D3 - what a fight to even get tested for that! I do find that makes a difference, but it's never been rechecked to see what my levels are....


I feel exactly the same,I am constantly at the Doctors ref my weight gain,Up to 6 months ago I was on 200 mcg Levothyroxine, I am now on 175 mcg and I have type 2 diabetes which the Doctor has seen that I can control with watching my Diet, so how come my weight is gaining on average 4 lbs a week. He seems totally baffled so I understand how you feel....


How are your levels of Ferritin Folates Iron B12 and VITD ? They all need to be high in the their ranges - so do NOT allow your GP to tell you they are Normal - when in fact they are at the bottom of the range. Iron needs to be good for you to convert your T4 into the ACTIVE T3.

Maybe you are not converting well and a FT3 test would help to flag this problem up. Labs seem loathe to do it due to expense I believe. There is information on the main Thyroid UK Website about the Gene Test for D102 - if you have that gene then it indicates your problem with converting T4 to T3. Maybe at least show the article to your GP and ask for the FT3 test along with the TSH and FT4 and the above mentioned Vitamins.

Remember also that your T4 is a storage hormone and it may well take several weeks before your body is depleted and you once again feel unwell....also less to convert into the ACTIVE T 3.....

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I continued to gain weight when I first started on Levo, it took 18 months and calorie counting to get rid of 6st, I still have 1st to go but I had to be very disciplined with my diet and would often go for weeks and weeks with no weight loss which I'm sure is due to my thyroid.


Similar experience here - I put on 5 stone in a year when they zapped my thyroid and put me on levo 5 years ago. Glib doctors advised dieting, but dieting didn't make an ounce of difference. Very upsetting. At least my weight reached a plateau and I could start buying clothes again without growing out of them in a few months - even if they did have to be 4 sizes bigger!

Now I'm using thyroid S and have lost half a stone this year. Fingers x-ed this slow weight loss is going to continue. If I can reach a lower, plateau a stone or so lower I might try dieting again. The killer is trying to keep weight off, of course.

I'm not recommending thyroid S - each one of us has a different reaction to the different meds available, as this site demonstrates in Spades. But finally I seem to have found something that works for me.


hi my son is on levothyroxine and hydrocortisone , he s 18 an was diagnosed with a brain tumour in november 2013, since he s been put on this stuff he s gained 4 stone in weight he was 13 stone ,he s now 17 an a half stone i keep tellin the docs he s eating properly but they seem to think he s gainin weight thru lack of exercise an he s not , whats this thyroid s thing , i m new to this an n e help would b gratefully recieved


Your poor son! That must be such a worry for you all.

Thyroid S is natural dessicated thyroid hormone (shorthand around the site is NDT). Doctors don't like to prescribe it. Those that do prescribe the brand 'Armour' usually. I am self-medicating with NDT. PM* me if you'd like to know more.

(* personal message - we're not allowed to discuss suppliers, doctors by name, or self-medication on the site, for obvious reasons)

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What isthyroid S I had my thyroid removed 30yr ago being on and off levothyrozine since felt no different but gained weight not happy so came off medication. Would like alternative options


As I say in my post above, it is Natural Dessicated Thyroid Hormone (often referred to as NDT). It is usually derived from either pigs or cattle. Thyroid S is available without a prescription from various places around the world. Taking Thyroid S has not helped me lose weight, but it does enable me to sleep, most nights.


Sorry it has taken me so long to reply to you lovely people! I have had a couple of months of blood tests and general bad health, but the upshot is that on top of my under-active thyroid I now have type 2 diabetes :( which might explain the drop in weight - although that seems to have stabilised....

I sometimes feel that the whole thing is so complex my head is spinning, I think I'll stick it in the sand until it stops!!

I'm now waiting on a referral to 'DESMOND' to find out how to manage the diabetes, it's all rather overwhelming to be honest. :(


This is a link for information:-

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You must immediately seek medical advice. Your Doctor will decide how best to proceed, but right now you on fumes.

It takes about 3 weeks for all of the Thyroxine in your body to completely disappear, if you are prescribed 125mcg (micrograms), I won't be Milligrams, then you are risk.

Suddently stopping your medication can result in DEATH !!!

You could have unseen damage to your organs and feel fine, until you collaspe into a coma.

Please please please see medical advice.


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