Side effects

Hi. Can Levothyroxine cause rapid weight gain or is that just down to my 'undernourished ' thyroid.

I have Hashimotos. I understand I've had it for a long time. I think my second pregnancy was the trigger.

After my baby girl I lost 3 stone on Slimming World. Then it stopped working for a year then I got diagnosed.

What I'm questioning is why suddenly I am rapidly gaining weight? Is it because I'm on higher and higher doses of Levothyroxine or is it because I'm not on the right levels yet....if it's the latter that confuses me as I've never been on the right meds.....

I am eating sensibly. I am gaining 2lbs a week currently.



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103 Replies

  • Every time i increased my dose i put on weight and hair loss goes up a notch. I have not been consistently optimal yet so can't tell you if it's that or not!

  • Arghhhh I was thinking it's got to be the Levo.

    VERY frustrating!!

  • I don't think you can assume that you won't lose it again though when you become optimal. It takes a long time doesn't it? My levels were temporarily optimal but i felt far from it and then 2 months later were back to where they started so i think its almost like that dry sponge effect people talk about and you have to wait a while to see what is really going on.

  • Its been a year for me and i am hoping that my next test will be optimal. Lost a couple of pounds with more walking in the last few weeks.

  • Oh I hope so too. My endo said it will all come off when optimal but how long it takes me to get there is like how long isxa peice of string!!

    My worry is it could take months and all the time I'm getting fatter and fatter and fatter.

  • I'm surprised your Endo said 'it will all come off ..'


  • Really? That's the hope I'm clinging onto!!

  • I hope he/she is right. I may have misunderstood. I thought the weight just stopped going on. We are all different though. And yes I have lost some weight since being on Levo.

    When I slip and put few pounds on it's now easier to lose when I go back to strict diet. It was almost impossible to lose before.

    Please don't give up hope!!

    It's only by staying positive that I can overcome my symptoms!


  • I'm normallya really up beat positive person. My weight gain is so rapid right now it's scaring me!

  • What are your Ft4 and Ft3 levels? Until they are optimal you are still hypo and will suffer hypo symtpoms. It should get easier to lose weight when your meds are at the correct level. People often find that a paleo-type diet helps (and not too much exercise, as that decreases T3, which is the hormone that runs your metabolism). If you have Hashis (autimmunue thyroiditis) a gluten-free diet also often helps.

  • Hi. I've been GF for over 3 months and it's made no difference. I have to eat it now as having a colonoscopy in May.

    My FT4 is 14.1 (9.0-19.0)

    FT3 is 3.9 (2.6-5.7)

    Basically been at this for 32 weeks.

    Levo is suppressing my TSH but doing nothing elsewhere.

  • I don't think it makes any difference to a colonoscopy whether you eat gluten or not. It just looks at physical changes. You only need to eat gluten for 6 weeks or so if you are having bloods done for coeliac. In fact I'm not even sure that a colonoscopy can detect coeliac as the damage is to the villi in the small intestine and you need an endoscopy for that. See

  • The gastro DR said to me to start eating it's made no difference to me eating it again....

  • Then it's probably not the problem.

  • Agreed

  • So you are undermedicated according to your bloods and need an increase in levo.

  • Yes agree. Going up again in 8 weeks and then again 8 weeks after that...

  • My levels were optimal on levo alone (150mcg) but I was very bloated (oedema) until adding in a small amount of t3. Can you get a trial of t3 and see if it helps? I have never had that level of fluid retention since and I can tell when I get symptom breakthrough (if I split my dose or the few times I've had to do without my t3) because it is the first thing I notice.

    The good news is that if it works for you all the fluid should just fall off. If there is weight gain aside from fluid that's a different matter but for me fluid was a big issue.

  • How do I know what it is? I'm big and puffy, totally bloated all the time, by the evening I look like I'm 9 months pregnant I kid you not. It's very uncomfortable.

    I'm finding being this big and gaining actually really embarrassing.

  • Well the usual test is to press a puffy area (like your ankle) w your thumb and hold it there for a while. When you remove it it may leave a depression in the flesh. That is oedema.

    It also feels different than weight gain. Oedema is stiff and hard and you may feel like your limbs are hard to bend and feel heavy. It can be hard to cross your legs because your flesh is so unyielding. If you try to pinch the flesh you may not be able to because a crease can't be made.

    My elbow joints were stiff and I felt like when I bent my elbow the flesh on my upper arm touched the flesh on my forearm, it didn't shrink back at the joint as it bent. I don't know if that is clear, but I can't think how else to put it.

    My limbs felt like balloons filled w air. Can't think how else to express it.

    Virtually as soon as I was on 10mcg t3 (as well as levo) the fluid went. I woke up in the morning and it had all just fallen away. My face looked entirely different too.

  • Oh gosh. I so want that to be me!

  • What is the t3 called did you get it from your gp..? As I find my knees don't bend ,thanks

  • Im not a doc but im certainly beggining to hate them and hate my eltroxin its ruining my life stolen my life. Put my brain in a prison cell.

  • I piled weight on - over years - on t4 and t4/3 combination. Initial addition of t3 helped, lost 1st, in a month, without doing anything different. But plateaued. Remember going on holiday one year, when got off the plane the other end was so bloated I could not fit into any of clothes I'd brought! And trying to get anything on my feet! Have spent years with increasingly swelling feet - going up a half size, then another... to accommodate. (Even when on t3 only) Dr said would like to see me lose a ST. Joined SW but I also started seeing an acupuncturist. Within a couple of weeks swelling gone - so noticeable.

    I had been on t3 only for a good couple of years when joined SW. I honestly believe that it was because my medication was so much more stable, that through SW the weight just seemed to fall off. I was not sticking to it 100% but in 11 months I lost 4 st. It felt like, without even trying.

    I still struggle with the swelling, particularly in the feet and ankles - I return for a few sessions to the acupuncturist, helps for a while at least.

    Problem I have - long term trying to get a diagnosis, decade+, then another 2 decades on t4, without benefit, with it becoming toxic in system, left adrenals compromised. So any stress now can leave me floored for some time. No matter how good thyroid meds are, if stress it impacts on ability to process meds. Lots of stress in last 18mths, fighting to get back on track. But I do know that being on T3 only gave me a life!

  • See this scares me. I don't want to thinknits going to take me so long. I won't let it. I would rather self medicate and buy all my own meds and blood tests.

  • endo has just put me up to 175. She said in 8 weeks I go up to 200. Then after that I go on 'combined' treatment....

  • I cannot for the life of me, understand why they're building your dose up so high, when they're only going to have to reduce the T4 again, when they add in the T3. If you are taking T3 - even a small amount, I doubt you need 200 mcg levo. I'm not sure your endo knows what she's doing. I hope that, at least, she will test the Frees before starting the T3!

  • She keeps repeating to me that my T4 and T3 need to be much higher...

  • But she doesn't want to give you the t3 to, er, raise your t3 - ? The mind boggles.

  • And then I bet when you're feeling better on t3 she will keep trying to force more t4 in to keep your t4 up because 'you need some t4 as well as t3'.

    What are the odds you need far less levo and a little bit of t3? Quite good I bet.

  • So what do I do?

  • What has your tsh been like? If you require your t3/t4 to be higher what will happen when your tsh goes very low if the t3/t4 are not high enough? They often lose their nerve and then start reducing levo.

    Have you felt any better on these increasing levels of levo? Are you improving?

    Off the top of my head you can either (1) stick w the current protocol in the effort to remain compliant and demonstrate that you're doing what you're asked, (2) ask why the levo is repeatedly raised when the outcome is still unimpressive and/or (3) propose that all this raising the levo is time-wasting and ask if you can just try some t3 now instead of being ill for the next two months.

    I appreciate that there is a plan, but does it need to be so long-winded at the expense of two months of your health?

  • My TSH is 0.261 (0.400-3.100)

    Has been that low for 16 weeks now

  • I would LOVE it not to be so long winded!! It's 7 weeks untill I see her again......

  • That's too long change doctors. Im busy looking for a new doct . these doc are so charming yet ruthless. Most of them.

    God help us.

  • 7 weeks is too long untill I see her again?

    Problem is it takes months to start and find a new one....

  • And how do you find one worth having!

  • Sorry. Lots of seperate replys from me. Does this basically mean I am not converting properly?

  • Generally if you're not converting you'd see quite a lot of t4 piling up, so your low t3/t4 is a bit different. Sometimes we just need more meds to get there.

    Tbh it seems like your doc is listening to you and wants you to feel better, she is even ok w your tsh being so low (for now anyway), so that is all good. We don't often hear docs caring about how high or low your t3 and t4 are.

    My concern is that for whatever reason the levo is not really helping you. Your hormone levels are still too low and you have symptoms on a good, meaty dose. If she carries on raising the dose you may indeed feel better, but can she weather the storm when your tsh is nil or will she then say, 'Oh yeah, can't have that, you need to reduce your levo' and then you'll be right back where you started.

    And why 200? That seems an arbitrary number beyond which she is not comfortable. Why not 300?

    And as above, if/when you do go onto 'combined treatment'? The levo will have to come down again, and that takes time.

    So what I'm saying is that she means well - no small thing - but these are the questions and thoughts that come to mind.

    I assume she is really pushing the levo so you don't go down the road of having to fight for t3 just as many of us are having it taken away.

    There is a test to see how much hormone is getting into the cells. I think it is a urine test - ? Maybe someone else can add detail, Idk much about it. Googling it seems to turn up a urine test to diagnose uat, which may be a different thing.

  • I'm in France and I don't know the 'protocol ' with T3 here....she's mentioned combined so she (after reading all this) bust be thinking I need some point!

  • Ok, I guess that explains why she is raising your meds. :-) And I think t3 is more accessible in France so you may not have the same issues we do in the UK.

  • She's never mentioned it untill last week when she said if 200 of Levo does not work then she will give me 'combination' treatment. She never said the words T3 tho

  • Well, that's what combination treatment is : T4+T3. And, if she just adds in about 5 mcg, it's not going to make much difference.

    What's more, I have my doubts that going up to 200 mcg will significantly increase your T3 - although it might suit you. Only time will tell.

  • Should I try to see her say in a month instead of waiting so long and ask for combination treatment?

  • Well, six weeks after you started on 175, when you get your blood test results.

  • If she introduced T3 what would be a good start? When my DR startedme on levo they gave me 50mcg.....and thus has not taken me over a year to get where I am now.....

  • 50 mcg is a normal starting dose for T4. It's a storage hormone, virtually inactive. It has to be converted to T3.

    T3, being active, has to be started much lower - say 5 mcg? And increase by 5 in two weeks.

  • Your FT4 is just mid-range - doesn't she think that's perfect? Most of them do. lol Your FT3 is below mid-range, so your FT3 needs raising more than your FT4.

    But, I'm surprised that your FT4 is only mid-range on 175 mcg. How do you take your T4?

  • Every morning around 7am with half a pint of water. I then eat after 8am...

  • All the time she says my 4 and 3 need to be at the top

  • Do you take any other supplements or medication?

  • Yes. I take all the stuff you told me to 😊

    At 11 I take B12 and B complex, at 4 I take selinium and zinc and then at 9pm I take iron and Vit C

  • Ok, so they're all well spaced away from levo. But, there does seem to be some sort of an absorption problem. You're not taking a PPI, are you?

  • I don't know what PPI is!

  • Something like Omeprazole, that stops acid production in the stomach. Doctors hand them out like sweeties!

  • No. I have nothing like that. In fact everything I take I've listed. I do however have terriblestomach issues, bloating that physical hurts and I always have diarrhoea. I am having a colonoscopy in may.

  • Yes, but that won't tell you what's going on in your stomach. Have a read of this :

  • Ok I've just looked....however, I never have heartburn, before I was on levo I would have really big build ups of gas in my tummyand it would hurt and I would spend all night cramping and burping....I would take about 9 Rene a night just to get some sleep.....since levo I very Rarely get this......I just have unbelievable bloating and diarrhoea.

  • Just a thought. Have you considered if your adrenals are working correctly? Might be impacting on the uptake of the medicines you are taking.

  • I have no idea where to start with that. How do I know/find out/address?


  • I found out this was at least partial my problem, when I went to see Dr P, I was not coping with any level of stress at the time, would be quite ill...shaking and floored! I did order some private adrenal tests - can't remember the company name but if you look up on Thyroid UK you might find more information on there. I would suggest you, maybe, read around adrenal issues first to decide if it is worth pursuing this line of enquiry? It may not relate to you, and there will be a cost.

    If I can find the name I'll try and PM you.

  • Do you think this could be relatedto no gall bladder?

  • I don't think sick gall bladders cause stomach pain - mine didn't cause any symptoms at all, it was discovered by accident, full of stone.

  • Do you think I'm wasting my time....and having a unnecessary general anaesthetic for all of this? Do you think this is all thyroi and not medicated properly issues?

  • I have read (famous last words) that because I have no gall bladder I could have salt absorbsion issues.....meaning I just have absorption issues?Meaning I'm not converting?

  • No, I don't think you're wasting your time. I think it's good to cover all angles, just to be sure.

    I have never heard that having no gall bladders means you can't absorb salt - how is your sodium, on the test? But it's perfectly possible that you aren't absorbing stuff well - I think it's pretty likely. Are you still taking the omeprazole?

    Absorption and conversion are two different things. One does not necessarily preclude the other. On paper, you conversion doesn't look too bad - not brilliant, but not too bad. But, you need more T4 to be converted, and you just don't seem to be absorbing it. You need to know why.

  • So then I ask how do I find out why?

    No, innever tske renne anymore.

  • Rene is not a PPI. But it contains magnesium, so could stop you absorbing your hormone.

  • Can I just clarify then please = I will bring my endo apointment forward a week or two if I can - then when I see her I ask not to be put on to 200 of levo I ask to start the combination treatment asap.

    I will carry on and go for my internal camera investigations.

    Good plan?

    Also sorry - I find this ALL so compicated - do you think its my lack of T3 thats making my rapid weight gain? Or do you think its the levo?

    I have just bought some Magnesium spray and will start that over the weekend.

    Thank you!

  • That sounds like a plan, but in the meantime, do read that article about low stomach acid, and do the test.

    If your FT3 is low, then it will that that is responsible for your weight gain. It's low T3 that causes symptoms.

    I'm sorry, you've lost me with the magnesium spray. Where does that come in?

  • OK re plan for Endo.

    Well my FT3 is low (its certinaly not high) so at least I can stop beating myself up mentally that im eating or doing something wrong. Its just rubbish that its so visable.

    I will do the stomach test on Monday and write back on here what the result is.

    Re the magnesium - sorry - Ive kinda just added that - it was to do with the question re do I take any supplements - I take all the ones you suggested and one of the ones I dont take is Magnesium. I did try a tablet fromat of Magnesium Citrate but it literally wipped the floor with me - I'm sure I have a massive reaction to it so I dont want to take it - Ive bought Magnesium skin spray which has just arrived today in the post.............

    Thank you greygoose hope its not raing lots where you are! It is here.

  • It's a beautiful spring day, today, and the air is sweet.

    Good luck with the endo! :)

  • Ohhhhhhh that makes me Jelous - Tho we are expecting sunshine all next week - fingers crossed.

    Do you think I need to take the Magnesium - it can only help right?

  • It can only help. :)

  • Sorry, sorry, sorry!! Quick one....can I take the spray Magnesium aroun the same time I take my iron and Vit C?

  • You can take it any time you like, because it doesn't touch the stomach.

  • Of course!Thank you x

  • It is a very complicated issue. It affects us all in many similar ways but, probably, just as many different ways! You should not be sorry -

    good luck.

  • I'm butting in here go forgive me but can I ask, did you have your gall bladder removed or leave it since no pain?

  • The surgeon advised me to have it out because the stones were very small, and could get out of the gall bladder, and get lodged somewhere else, which would have been more serious. And I didn't know enough about it to contradict him. So, out it came.

  • Thanks Gg I asked because a friend in similar position and was advised to have it removed but has doubts due to others saying they had big problems with no gall bladder and is undecided to go ahead or not.

  • Not having a gall bladder has never caused me any problem that I know of. I still live and eat as I did before.

  • I was in agony with mine - it was infected with stones so havd it removed - as far as im concered not ill effects since and i eat and drink as normal but...........I'm clearly having issues now.

  • Im not a doctor but seriously if a medication is supposed to make you feel beter but making u feel worse then really what is going on with these doctors.

    I woke up this morning feeling ok i took my eltroxin meds.o5. Mg. And now im feeling aweful beyond words. Buzzing pressure on my brain and ears and pressure on my chest. Low

  • TSH can become irrelevent when at low levels. So unless it rises I would ignore it. Luckily I am on NDT so I don't get these problems.

  • I put on a huge amount of weight over the last few years. I was diagnosed nearly 12 months ago and found to stop gaining I had to restrict myself to a very low carb/high protein diet of 1200 calories. It was miserable, despite dose raises every 2 months with no end in sight, however in the last 3-4 weeks my levels have suddenly righted themselves.

    I could have pee'd for england the first week and dropped so much fluid out of my calves and feet that ive gone down a shoe size! It is still not easy but I have dropped 12 lb's and even if it was mostly fluid 3-4 lb's is more than I have lost in a month for a very long time, hopefully if they can find your 'sweet spot' you will be able to do the same.

  • Ohhh I'm truly happy for you! What 'diet' are you following or have you kinda made your own up?

  • I had previously had success years ago with slimming world but i found this time I had to follow the red days (high protein, carbs measured as sins) rather than the extra easy plan. and green days were a total no no! The whole idea is you dont count calories but i found that just wasnt viable for me so did a bit of adjusting to eat the red foods but within a calorie limit of 1200, i also went gluten free. The app my fitness pal or similar was helpful as its database saves you having to work all the calories out manually and you can save meals.

    I wasn't going to pay for class when unable to lose (and messing with the plan) but still had my old books, (you can usually find them on ebay). Obviously if you want the support then joining a group or online is helpful. The plan looks complicated at first but it doesn't take long to get your head round. If you fancy giving it a try I am happy to help.

    My test results are all on my bio and show how big a change can suddenly occur with no warning 😀 so there is hope. I am now going to the gym and can have a whole 1500 cals, whoop whoop!

  • This is interesting to me.

    When I had my daughter two years ago I did SW, I did mostly green days as my husband is a, I lost three stone quite rapidly but then it stopped. It just totally stopped. I think this and my pregnancy is what triggered my hashimotos.

    So for a whole year I stayed on plan, I didn't loose, I didn't gain, I had no idea what I was doing wrong.....then all this happened and now I get it! Now tho I'm in rapid gain mode and I've put one one and a half stone.....

    I'm more than happy to 'tweak' the plan, I refuse to syn oil if I'm using a tiny bit in a pan. I've been kinda trying to do it mostly to limit 'naughty food' like cake, chocolate, crisps etc.

    What I've been doing potentially wrong is trying to do speed days to often and they bore me.

    Red days are more a achievable. I won't use sweeteners but I rarely have sugar anyway....

    I'm going to find my books now and look thro them 😬

  • I dont have hashis but i know a lot of people on here who do have it recommend gluten free to try and reduce flares and antibodies etc, Ive just tested negative but dont want to fall back into the crusty bread and cake trap as im not very good when it comes to having just a little bit, i either do or dont,i did find after a couple of weeks it stopped me craving most of the naughties which was helpful and made it easier to stick within the calorie limit i chose - i take a chunk of slimming world quiche to lunch rather than a sandwich now and stuff it with loads of speedy onions and mushrooms, mmmm

  • Hi,I too struggle with my weight and I have to cut back on my syns if I want to lose weight. While others can get away with a sneaky dash of oil, an odd slice of bread (in addition to my HE!) or the odd glass of wine, and not count it, I can't - even eating gluten causes a weight gain for me, and it's possible you are the same. So I try to stick to between 5 and 8 syns and this will give me a steady loss of about 1lb a week - it's tough going and has taken me ages to lose 20lb. I had a test for coeliac disease yesterday, in the 6 weeks leading to the test I gained in the last 4! I'm hoping now that I can go back to the plan and start to lose again😃. Good luck with your journey x

  • You too - Miserable isnt it!

  • Hi, I'm new to this site, having been recently diagnosed, and find the comments really useful.

    I initially started on Levothyroxine from a company called Mercury Pharma, they were wonderful, like little magic pills and I couldn't believe that for approx 13 hours a day I felt 'normal' - no pain, no constipation, no foggy head, no lethargy, honestly, they were fantastic. I collected the new prescription to find it was the same meds but different supplier. The new ones are by Tevo I believe, a new formulation too, and I am back to struggling again, carpel tunnel is back, tennis elbow is back and hip (need a replacement at some point) is playing up.

    Bit long winded, sorry! The question I wanted to ask is - does anyone else have this problem?

    Dee 😉

  • Hi Dee, you are not alone, whilst I havent come up against this are a lot of people who find the same, I believe it is often assiciated with differing fillers and slight variations in strength. It is worth checking with the pharmacy if they have your prefered brand in stock or can get it in, if not take prescription elsewhere. If you really struggle you could try asking your gp to do named brand only on the prescription so pharmacy has to get it, just leave yourself an extra couple of days!

    Ps I always get given MP by Tesco pharmacy, they may all use one main supplier, worth a try😁

  • Many thanks for your advice - I have seen the Dr and had a new prescription. The pharmacist was very good and tried to match my medication to the brand that I did well on (mercury pharma - but they have lost their licence to produce 50mg at this moment in time). Whilst he was checking the ingredients he noticed that the tevo brand had an ingredient called manotil and he believed me to have an intolerance to that which caused inflammation and swelling.

    I'm now trying actavis and so far so good!😃so if you find that Tesco struggle to get MP then Actavis might be a good alternative for you. 🌷

  • I obviously jinxed it, my 100 and 25 prescriptions are out of step and Tesco just gave me Wockhardt not MP 25s. oh well Ill try anything once and as I am feeling reasonably well at the mo any issues should be obvious.🤞🤞I didnt find any issues with actavis 50s but to be honest I was so poorly controlled at the time I probably couldnt tell so will be interesting to see how you get on. If worse comes to worst see if they will let you have MP 100's with a pill cutter 🔪🔪

  • Yes, that's a good idea, I will see how I am with avitas but will keep that in mind. I will let you know how I get on.

    Good to hear that you are feeling well now after your initial struggle, hope the wockhardt work for you. 🌷

  • Don't worry once your levothyroxine is at the right dosage for you and you make sure you are eating at a calorie balance that will help you loose weight you will be fine (it just might take a while). The problem with not tracking calories is that you could think your eating sensibly but the portions could be too big or there could be a lot of calorie dense foods in your diet like coconut oil and nuts or nut butters etc. if you need a hand with anything diet related feel free to send me a private message I actually studied nutrition and have hashimotos / hypothyroid myself so I am more than happy to help you try to find a simple method to keep you at maintenance point until your dosage starts working for you :-)

    I am currently maintaining my weight even though I'm still in the Hypo range at the moment so don't despair it can be done :-)

  • Thank you :)

  • Thank you so much - I go to slimming world and follow the plan, I agree that it's so easy to overeat and I often did! 😣

    I am much more sensible now as the weight goes on so easily so if I have nuts I only have between 2 and 6 depending on my calorie count that day (they call it syn allowance). I've also purchased new bowls for chilli etc to ensure portion size is moderate.

    Today I am due to weigh and I've woken feeling heavy and bloated thinking that I might not go today and might give it up!!!! Your message made me rethink, you clearly know what works for you and its good to hear that it can be done . You have done well to maintain your weight. Any dietary advice is very welcome 🌷

  • Go to your weigh in Dee1304 and definitely don't give up :-) it's not the end of the world if the scales say you are up a bit this week alot of things can influence the weight on the scales as well especially with women. Hormones have a big role to play too and depending where you are in your cycle it is normal to hold a bit of extra water in your body which will leave you feeling bloated and "heavy" but that is only temporary.

    You sound like you are on the right track with watching your portions which is great! smaller bowls and plates definitely make a big difference. Also filling up on water during the day can keep feelings of hunger at bay so make sure you are drinking about 2litres a day. It will take a bit longer than normal especially because of the Thyroid but you will get there.

  • Thank you for your support Karen, I went to SW and weighed - I didn t lose but the good thing is that I didn't gain! Hoping this week can see a turning point. Thank you for your advice, I will up my intake of water during the day - I always drink a couple if pints if water in the evening but often forget to drink water during the day so that's a good reminder 🌷x

  • Hi I was over weight before but have lost all my extra weight and my hair and nails are in great condition!!Down side I feel ill (flu like) every morning and struggle to get out of bed....I have been in tablets about 6 months...

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