How Methimazole Leads to Weight Gain & What to Do About It

How Methimazole Leads to Weight Gain & What to Do About It

Methimazole, the antithyroid-blocking medication used to treat hyperthyroidism, can lead to weight gain in certain individuals.

But how does this work?

How can you gain weight if you have hyperthyroidism?

The answer has to do with how methimazole works in the body and how it blocks thyroid function.

Learn more about methimazole, how it can cause weight gain, and how to lose weight if you have hyperthyroidism here:

What is Methimazole & How does it Work?

In order to understand how methimazole leads to weight gain (and yes, it can cause weight gain) we need to understand how it works in the body.

Methimazole, as you probably already know if you are taking it, is a medication that is designed to treat hyperthyroidism.

Hyperthyroidism is a medical condition that results in excessive thyroid hormone production in the body.

This thyroid hormone, released from the thyroid gland, causes the activation of thyroid hormone receptors in the body.

This activation ramps up the metabolism (1) (usually making patients lose weight), increases heart rate (causing palpitations), increased adrenaline release (making you feel jittery and anxious), and leads to diarrhea (through activation of the GI tract).

If you have hyperthyroidism then you probably understand all of these symptoms and have experienced them.

So where does methimazole fit in?

Methimazole acts to block the effects of hyperthyroidism by inhibiting the PRODUCTION and ACTIVATION of thyroid hormone in your body (2).

It does this by blocking an enzyme known as thyroid peroxidase (3) which is responsible for producing thyroid hormone.

It also blocks the peripheral activation of T4 to T3 in your tissues reducing the amount of circulating and active T3 thyroid hormone.

The net result?

Decreased thyroid hormone production and activation in your body by blocking thyroid function.

This is all well and good but you have to realize a few very important points:

#1. Your thyroid, when working properly, helps manage your weight.

#2. Methimazole is dose-dependent and acts differently in each person.

#3. Over-blocking thyroid production may lead to a state of HYPOthyroidism

These three factors are important in understanding how methimazole can lead to weight gain in certain people.

It has also been shown, in aminal studies, that long-term use of methimazole may cause weight gain and other harmful side effects to the body (4).

Animal studies do not always cross over perfectly with humans, but they can still act as useful tools that we can learn from. 

These negative side effects, seen in animal studies, may be mediated through the anti-thyroid action of Methimazole.  

Like anything in life, we need to try and achieve a balance, and if the balance is tipped in favor of hypothyroidism over hyperthyroidism, then there may be negative consequences. 


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Does Methimazole Cause Weight Gain?

So what does this mean for you?

It means that it is entirely possible that taking methimazole may block the normal thyroid function in the body and lead to weight gain.

And this should actually make perfect sense once you understand the physiology.

The treatment of hyperthyroidism is to BLOCK thyroid hormone.

But blocking thyroid production, in a perfect way, is easier said than done.

We know from studies such as this, that it is NOT uncommon for patients to gain around 5kg or 12 pounds when they start methimazole (5).

This study showed that among 42 patients with Graves’ disease that the average weight gain was around 12 pounds after starting methimazole. 

Doctors know that this often occurs, but the question is why?

Your body, naturally, has many different feedback loops internal and external factors which regulate thyroid hormone activation and production very closely.

This is happening ALL the time in your body whether you realize it or not.

So does it make sense that you can put someone on a thyroid blocker like methimazole and expect to perfectly balance thyroid hormone in the body?

Not really, at least not for every person.

There’s also another very important point to consider:

Doctors would prefer patients to be HYPOthyroid over being HYPERthyroid due to the side effects of hyperthyroidism.

It’s also widely believed that treating and managing hypothyroidism is easier when compared to hyperthyroidism.

For these reasons, it’s not surprising that some patients may experience weight gain after taking methimazole because their dose is either too high or they are sensitive to the medication.

So does methimazole lead to weight gain?

It absolutely can, and it does this by slowing down your metabolism and reducing the amount of energy that the body produces at baseline.

It’s well known that weight gain is a negative side effect of hypothyroidism and it is something that I’ve discussed in detail here.

It’s also well known that having low T3 (a side effect of taking methimazole) may lead to weight gain as well.

Now, some of these side effects, while unintended, may actually be necessary.

For instance:

We don’t want to have excessive thyroid hormone production in the body causing long-term issues like heart problems (6) (atrial fibrillation or cardiac enlargement) or excessive bone loss leading to osteoporosis (7).

But, on the other hand, we also want to balance thyroid hormone to prevent weight gain, depression and cholesterol issues (all side effects and symptoms of hypothyroidism or an indication that your body is swinging from hyperthyroidism to hypothyroidism).

This balance may be difficult to achieve with methimazole, but it is always worth attempting.

Sometimes it may be possible to simply reduce your dosage which will allow some thyroid hormone activation and production in your body.

A small change in your dose may be sufficient to restore some thyroid function (without causing the symptoms of hyperthyroidism) which can help manage your weight.

As a reminder:

Never alter your dose without consulting with your physician first! You may cause more harm than good if you adjust your medication in this way. 

How Hyperthyroidism Can Paradoxically Lead to Weight Gain

Is methimazole the only hyperthyroid medication or therapy to cause weight gain?

Not at all, in fact, most hyperthyroid therapies and medications will eventually lead to weight gain.

It has been shown in studies that all treatments for hyperthyroidism result in “marked” weight gain (8).

This weight gain is worse if you go into hyperthyroid treatment already being overweight or if you have Graves’ disease. 

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The average weight gain in these patients ranges from around 10-15 pounds or an increase of 8.49 in BMI (a huge increase!). 

Other studies have shown that after hyperthyroidism treatment patients have a 32% increased risk of obesity and most of this weight gain occurs in the first 2 years after therapy (9).

So we know that this is not an isolated phenomenon, but how can it be? 

How can you actually gain weight if you have hyperthyroidism, isn’t hyperthyroidism supposed to cause weight loss?

While the condition of hyperthyroidism does lead to weight loss, this is only true when it is not being treated.

Once you start treatment (whatever that may be) the goal of that therapy or medication is to block thyroid function.

Effectively this makes you HYPOthyroid (at least in most cases).

This can obviously be confusing for patients, but it doesn’t have to be.

Having an understanding of how it works in your body will help you determine how to treat it.

Are there different degrees of thyroid suppression?

The answer is yes.

For instance:

If you have had your thyroid removed or if you underwent radioactive iodine ablation then you will have a more difficult time losing weight when compared to someone who is taking methimazole or PTU.

The reason for this is that methimazole only blocks a portion of thyroid function in the body.

While having your thyroid removed completely eliminates all thyroid function in the body and makes the person without a thyroid completely reliant upon thyroid medication for life.

Because of the way that thyroid function is naturally regulated by the body, it is much more difficult to try and “normalize” thyroid function with thyroid hormone replacement medication. 

Remember that your thyroid produces thyroid hormone constantly throughout the day. 

And the amount of hormone that each tissue needs is delivered based on that need. 

It’s impossible to completely replicate this innate system in the body by taking thyroid hormone medication (though that shouldn’t stop us from trying). 

But just because these therapies and medications may make weight loss difficult, it doesn’t mean that losing weight is impossible.

How to Lose Weight with Hyperthyroidism

Is there a way to lose weight if you are taking methimazole or other thyroid blocking medications?

The answer is yes, but it may be more difficult.

You have to consider that you will be at a disadvantage trying to lose weight if your thyroid is being blocked.

Blocking your thyroid will result in some suppression of normal metabolic function.

What do I mean?

Basically, if your thyroid is blocked sufficiently then you may be burning fewer calories at rest when compared to normal healthy adults.

This means that general exercise and dieting is usually not sufficient to effect significant weight loss in the person.

So what are you supposed to do?

It depends on each situation, but the goal should be to focus on your options.

If you are post-thyroidectomy (meaning you don’t have a thyroid) then it’s best to look at your current dose of thyroid medication and to optimize that dose to get your free T3 levels in a high enough range (you can read more here).

The same is true if you are status post radioactive iodine ablation which is another method of destroying the thyroid gland to treat hyperthyroidism.

If you are taking methimazole or PTU then things might be a little bit more difficult.

These medications act to block the thyroid but they are highly dose-dependent.

So if you are on these medications you will need to take a close look at your current dose to determine if you are taking too much or to see if you can reduce your dose.

Reducing your dose will allow more thyroid hormone to function which may increase your metabolism.

But it will be a balance of trying not to block too much thyroid and not blocking enough so it can be difficult.

It may be tempting to opt for a therapy such as having your thyroid removed or getting radioactive iodine ablation to treat your hyperthyroidism but these options are not necessarily better.

Instead, you may want to focus on therapies to try and improve what little thyroid function is left in your body with techniques such as these.

You may also find benefit in trying to reduce inflammation if your hyperthyroidism is caused by Graves’ disease (which is an autoimmune disease) with some strategies such as these

Just realize that attempting to lose weight with hyperthyroidism can be very difficult.

Wrapping it up

Methimazole can absolutely cause weight gain and it does this by blocking thyroid function and activation in the tissues in your body.

Over-blocking thyroid hormone may actually take you from hyperthyroidism to hypothyroidism which may then trigger symptoms such as hair loss, weight gain, fatigue, constipation and so on.

It may be possible to manage these symptoms by taking a close look at your dose and altering your dose if that makes sense.

You should look at your dose in conjunction with your current physician and your lab tests.

When optimizing thyroid function make sure you shoot for the optimal lab tests which you can find here.

Now I want to hear from you:

Are you suffering from weight gain while taking methimazole?

Have you been able to lose weight despite it being difficult?

What strategies worked for you?

Share your thoughts and comments below!










the methimazole and weight gain connection

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About Dr. Westin Childs

Hey! I'm Westin Childs D.O. (former Osteopathic Physician). I don't practice medicine anymore and instead specialize in helping people like YOU who have thyroid problems, hormone imbalances, and weight loss resistance. I love to write and share what I've learned over the years. I also happen to formulate the best supplements on the market (well, at least in my opinion!) and I'm proud to say that over 80,000+ people have used them over the last 7 years. You can read more about my own personal health journey and why I am so passionate about what I do.

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75 thoughts on “How Methimazole Leads to Weight Gain & What to Do About It”

  1. I was diagnosis-ed with both Graves disease and Hashimoto’s. I am currently on 10mgs of methimazole my dr keeps switching every month from 10mg – 20mg. This has been pretty miserable I no longer have the symptoms of heart palpitations and got rid a small amount of muscle weakness, as well as my eyes, quit swelling. But I gained 50 pounds in six months, massive hair loss, and terrible fatigue. My dr still either says my labs are normal or my labs or bad meaning that I went hyper again. This is an extremely frustrating process but I do not want to do RAI which seems to be my only other option. I would love there to be a third option my quality of life sucks. I’d love to find some strategies to feel better on methimazole and lose weight but I have yet to find any!

    • Hi Brandi,

      The third option would be to try alternative therapies such as diet, supplements, etc. to try and see if your hyperthyroidism is responsive. If so, then you may be able to avoid RAI or thyroidectomy.

    • It’s really depressing to have first of all gained 50 pounds On methimazole and I have not been on medication for three years and cannot lose 1 pound and when I do all I have to do is eat a peanut and I’m back to 3 pounds heavier. Is there any hope of ever losing weight again now that I am not on Methimazole anymore.

  2. I have been on methimazole for 14 months and have gained 21 pounds since. I eat plenty of fruit, restrict sugars, don’t drink soda, etc and the weight just keeps piling on. I was diagnosed with Graves disease, and don’t know how to keep the weight off, short of starving myself and exercising to exhaustion.

    • Hi Courtney,

      The next step may be to evaluate your current dose of methimazole to see if it is suppressing your thyroid function more than necessary.

      • It’s me sumitra, I already used methimazol1 month twice a day it’s my second month how many doses I have needed for per day

  3. I went on Methimazole in January of 2017. Diagnosed with Graves at 39 years old. Fifteen months later and a total weight gain of 50 pounds and I’m completely miserable. My labs have been getting significantly better since November and a number of negative side effects have come and gone. Except for this devastating weight gain. I have constant fatigue and am very depressed. I’ve done everything my Endocrinologist suggests. It’s just all so hopeless.

    • Hi Beth,

      It can definitely be difficult. Your thyroid controls up to 60% of your metabolism so even slight changes to it can alter your weight very quickly.

    • My daughter is 7. She was diagnosed with Graves a year ago. She lost 5 kgs in 15 days. Post methimazol (carbimazol) alternating 5mg and 7.5 mg she has now gained 12kgs. Her cholesterol also shows high. We as a family eat healthy and exercise. How do I help my little one.

  4. I gained 30# after diagnosis of Graves and subsequent Methimazole therapy. I believe the weight gain was the result of inactivity because of feeling tired and achy, overconsumption related to the Hyper appetite and quitting smoking which was simultaneous. I insisted on only 5 mg low dose which may have delayed my initial progress and my numbers did improve some but I still had symptoms, after an increase to 10 mg I am symptom-free for the most part. For four weeks I applied my new energy to daily walks and moderate weight lifting, I began a ketogenic diet. I have lost ten pounds and my energy is improved. I believe the keto diet and exercise has helped my symptoms and that a calorie-reduced low carb diet will be effective even with thyroid problems. One aspect I should mention is that I consume my calories in a six or eight-hour window. Good luck.

    • Hi Susann,

      I would be careful with calorie restriction, especially with thyroid disease. Calorie restriction always works at first but it’s only temporary. The weight will always come back within 12 months or so and then the calorie restriction won’t work at that point.

  5. I have been on methimazole since 2012 after being diagnosed with Graves Disease. I gained 12 pounds instantly in 1 month. I have stayed the same weight since then despite exercising and diet. Nothing will change the weight. Is there anything you can recommend to assist in weight loss? I would only like to lose 15 pounds or so.

    • Hi Natalie,

      Your best bet is to try alternative therapies such as supplements, dietary changes, stress management and so on. Alternatively, you can also try altering your dose of methimazole under physician supervision.

      • Is there something else besides methimazol naturally that can help with graves? I was currently on 10 mg of methazole and it made me hypo, so I off it for 5 days, then down to 5 mg a day .not sure what to take for the heart raise because of the switch? I normally take motherwort for higher heart rate when I was hyper and not sure if i can still take it?

  6. I was diagnosed with Grave’s almost 3 years ago when I was 18, and have been on and off of methimazole since then. The past 5 months, I have gained more than 20 pounds, although I am young, healthy, and very active. I have been really frustrated and upset, unable to find any possible explanation- except for maybe this. I am on higher doses of methimazole than ever after the lower doses failed to work, and I am also considering radioactive treatment though I am concerned for the effect this will have on my weight as well. I know getting my thyroid in check is more important than my weight, but as a young woman the huge weight gain has been incredibly upsetting and I am glad to see others have experienced this as well, as sometimes my friends and family think I am making it up.

    • Hi Trina,

      You are certainly not alone as almost everyone who undergoes thyroid treatment for hyperthyroidism gains weight. Thanks for sharing your story and sorry to hear about your struggles!

  7. I was diagnosed as hyperthyroid in October of 2017. I have maintained weight within 5 pounds my entire almost 60 years of life, other than my 3 pregnancies. I began Methimazole in November 2017. By February 2018, I was up 12 pounds. I completely altered my diet to clean eating and began working out 3-5 days each week. The pounds kept multiplying on.

    At my last blood draw, come to find out I am now hypothyroid. My Dr. told me to stop the medication.

    It’s been two weeks since quitting Methimazole. I have further restricted my diet and added weights to my exercise regimen. I am still gaining weight, even without the medication.

    I might add that my doctor stated there is zero correlation between Methimazole and weight gain. This is physiologically incorrect!

    • Hi Georgene,

      As you suggest, it would be a silly to say that something which blocks thyroid hormone function doesn’t lead to weight gain, considering your thyroid helps control the majority of your metabolism.

  8. Good morning,

    I stumbled across your page while looking for answers. I was diagnosed with hyperthyroidism in September of 2017 and was immediately placed on methimazole 5 mg (2 in morning and 1 in evening). By Dec, the doc was very impressed with my numbers – said that if it continued to be this way in 6 months, we would talk about reducing dosage. Fast forward to March, I started working out and watching what I eat (Paleo/Ketogenic). I started JuicePlus supplements in November 2017 (also D3 at the time of diagnoses per orders); and last week, I started taking calcium, magnesium and a turmeric supplement (for my bad knees). The working out is mostly bodyweight training, but I also added walking 2-4 miles daily. After 6 weeks of this, I still have not lost weight BUT I do feel exceptional (actually since I refuse to step on the scale I don’t know if I lost any weight but I thought clothes would be looser than they are now)! Also, I neglected to add that doc also prescribed propanol (10 mg) for as needed for the palpitations caused by hyperthyroidism. I stopped taking this when I ran out the end of April. Now I am seeing my heart rate rise again. Mostly in the 80s but not near as bad as when I found out (it was in the 100-110s). So – could the keto diet be aggravating my now underactive thyroid (due to meds)? Or is it because I quit the Propanolol? I am so confused. My next appt is June 5th. Sorry so long. 🙂

    • Jacey – I have the exact same story as yours…please update me on what is working for you…I gained so much weight …I am doing IF, Keto and still furstrated.


    • I was able to stop the heart propranolol by using CBD, 1 syringe of the tincture, and completely changed by diet to be gluten-free, wheat-free, very little sugar, Himalayan salt only, NO eggs and or dairy (almond milk only) and I only eat a little meat, mostly vegan, including vegan cheese. Plus NO ONE on this panel is talking about the underlying THYROID CAUSE, which is “not feeling like you’re living the life YOU want to and not feeling like you have a voice!” So if you meditate, which I do (I use an app called Aura) and let go of the trapped energy, emotion in the thyroid, you will start to heal. My numbers went back to normal within 60 days and my dose of Methimazole has been lowered to .25 mg, I was started on 20 mg. then to 10, then to 5 now to .25 and I am going to start weening off. I have seen some weight gain, I am normally 125 lbs., 5′ 8″ but feel big in the stomach area and arms, my legs are still very slim but I feel the change. Still working on the underlying cause, staying healthy, I spin 3 x a week, walk and just trying to get happy. That is THE KEY! ALL DIS-EASE, no matter what label we get it, it actually A GIFT from our body trying to give us a message. Until we tap in and get that message, dis-ease will just find another way to get our attention. Hope this helps!! XO

  9. I was diagnosed with Graves almost six years ago. My weight dropped from 220 to 140. I was happy to lose the weight as several chronic pain illnesses keep me from being able to exercise. Well, I decided that the benefit of the weight loss was greater than the benefit of the medication, so I’ve been at ridiculous levels since diagnosis. Because of my choice, I now have thyrotoxic myopathy. I don’t know yet how advanced it is, but after six years, my guess would be advanced enough. At this point, all I can do is hope and pray that the methimazole will regulate my thyroxine enough to halt the myopathy. I have young children, and because I was worried more about my weight than my actual health, I may not survive my choice. Please, please take your medication. It’s not worth the consequences if you don’t.

  10. I was diagnosed with hyperthyroidism with nodules on the right side of my thyroid in 2014. At that time, the doctor did not put me on any meds. I had some tests to see how my iodine levels were and they were normal. Fast forward to January of 2018. After a routine exam and blood work, which showed that I was still hyperthyroid, my doctor ordered an ultrasound and a follow-up with Endocrinologist. Ultrasound showed nodules on right and left with small nodules throughout. He put me on 10mgs of Methimazole. I do not want to take drugs if I don’t have to, but the heart palps and anxiety caused me to try. I decided not to take the full dose, because the doctor warned I could end up with hypothyroidism. Instead I cut the pill in half. I’ve been taking this dose since June 5, 2018. I felt so much better, but I am fatigued, especially in the middle of the day. I have gained some weight, but nothing drastic yet. I have been trying to do it naturally with supplements since 2014. I would love to find an alternative to taking Methimazole.

  11. Seems there is no way out of some weight gain on methimazole. I was diagnosed with hyper throid over a month ago. I was placed on 10mg Methimazole. The symptoms were overbearing with hair loss, palpitations and arm joint pains making it unbearable to sleep. I just starting to feel better and my long hair started showing some life back, I hope that I won’t experience any weight gain as I started reducing my doses on my own after my last blood test indicate T4 free returning to normal after 3 weeks but my T-SH is still low

    Do you think this was a wise decision? My next appointment is a month away.

    • Hi Donnette,

      I wouldn’t recommend making any changes to your methimazole dose without supervision or approval from your Doctor. You don’t want to risk putting yourself back into thyrotoxicosis.

  12. Hi! I was diagnosed with Grave’s disease in April this year and I went into thyroid storm short time after that in May. Since then I had been put on Methimazole daily. It feels terrible. I am constantly gaining weight, I started with 60 mg per day, now I am taking 5 mg, but doctors insist on increasing the dose again as my thyroid is not stable. But I cannot lose weight! I cut my daily food intake almost in half and still no luck! Do I need to starve myself and reject food at all to lose weight and become myself again?:(

  13. Looking for some answers-
    Graves disease and put on Methimazole 10mg a day.

    I have gained 12 lbs and CANNOT loose it. I workout 5 days a week and have changed my diet to be very clean 90 percent of the time.

    Any advice? Im only 33 and working out without seeing the scale change is very frustrating.
    Thanks 🙂

  14. I’ve just recently begun taking 5mg of Methimazole for Hyperthriodidms. After basically suffering for a long time, waking from my sleep in a complete state of Afib, joint pains, anxiousness. You name it. My concern is that I’m also in a medically supervised weight loss program designed to help me lose weight for an upcoming surgery. My diet and exercise are strict, Very, STRICT. So I must know, is there anything that I can do to ensure that I continue to lose weight while being treated with this medication?

  15. I was diagnosed with Graves in November 2017 and I started taking anti thyroid medication Thyrozol. I started to gain weight after 6 months on the medication. Luckily, as of end of December 2018 my hormone levels were normal with minimal dosage and my doctor took me off the medication. So far my hormone levels have stayed in the normal range. But it has been very difficult to shed off the extra pounds. I have been patient but sometimes feeling hopeless. Is it normal for it to take this long ? I have seen a bit improvement but would like to see more being 6 months off the meds. I understand that with antithyroid medication it slows down the metabolism, but what effect does coming off the medication have?

    • Hi Katherine,

      It takes a while for the metabolism to catch back up. This process can potentially take years depending on the initial severity of the metabolic suppression.

  16. I was diagnosed with Graves’ disease in December 2016. At the time I weighed 125 lbs which was due to the disease. I started taking methimazole and my symptoms got better, but I began gaining weight. My doctor has adjusted my methimazole dosage over time and now I am down to 5 mg every other day. My doctor doesn’t want to reduce the dose any lower and whenever I stop the drug I become hyper again. I now weigh 145 lbs and no matter how I eat or how I exercise I can’t seem to lose any weight. I am worried I will keep gaining. Is there any hope for me?

  17. I was diagnosed with Graves/hyperthyroidism last month. The doctor said slight case, my “numbers” were just slightly off. Started me on 10 mg Methimazole daily. I’ve gained 15 lbs in three weeks. I track my macros. I’m in the gym every day lifting weights. I always stayed between 130-135 no matter what and could easily get off “weekend” weight within like 3 days back to my 130. I’m devastated. Last bloodwork showed numbers were back to normal. I asked if I could cut the dose to 5 mg and dr said yes. Tried that for two days but got really depressed so I just stopped taking it. Taking lemon balm, motherwort and bugleweed until my next apt in October. I am not willing to gain weight like this. I’m just not! I have always been thin and I’m finally getting muscles and definition and now it’s all ruined

  18. I’ve always struggled with weight. I was dx with Hashimoto’s via ultrasound in March, then flipped hyper. Diagnosed with Graves in May.
    I was in a thyroid storm because Graves was missed at first and I was still on levothyroxine. My thyroid labs are back in range. My antibodies are high. TPO is above 4,700, hit my TSI is down in the 200s from the 500s.
    My dilemma is I also developed idiopathic angioedema last summer and many good foods, including all fruit, cause lip, tongue, and occasionally airway swells (I. The beginning it was literally everything I ate and I nearly starved for two months. I lost 35lbs in a month).
    I’m getting more active, but I’ve gained an additional 10lbs. I’m 5ft4in and just hit 170. 🙁 I initially hit 186 when the hypothyroidism first hit. Before then, 150-160 was my normal range. Still over, but better than now. It’s frustrating. My now ex-husband was so mean about the weight, I always wished I’d be able to lose it. At least I know I have thyroid diseases now.

    • Update. I was in remission and did well. I came out of remission and have hit 200 pounds this time. It’s been almost a year back on methimazole and The weight is not coming off. My ex said he’d divorce me if I ever hit 200 and I thought that was impossible for me. My endocrinologist told me to just cut 500 calories, which would put me around 800 calories a day. Trulicity helped but my doctor ran out of samples and it isn’t for weight loss. So I exercise less than I was because I don’t want to leave the house during the day when people can see me and I’m exhausted by default. I haven’t felt well since this last bout with Graves.

  19. I was diagnosed with Graves disease 11 years ago. In the beginning I used to play with the medication, meaning I would take it and as soon as I would start to gain I would stop. Finally I went to a Dr that actually explained to me what Graves is and the dangers of not treating it. From that moment on I started taking the Methimazole daily. In 1 years time I gained 120lbs with no change in my diet or physical activity. I tried dieting and was losing like 10lbs in 3 months, which was not normal for me. I knew it was the medicine but the Dr said no it was me. A few years later I had the gastric sleeve done. Although weight loss was slow and never what the Dr’s expected I did lose 100lbs. 4 and a half years after I started gaining unexplained weight. Since January 2019 I am up 50lbs. I did weight watcher and was walking 2.5 miles a day and still gaining. Recently I start a low carb no sugar diet, I feel great however I have not lost a single pound and I am now on week 5. I also added in probiotics to the mix a week ago. Every time I try and speak with my endocrinologist he blames EVERYTHING but the medication. I felt like I was going crazy, I was proof that it had to be my medicine. Since I found this article I can NOT wait till my next appointment. I am just so frustrated that dieting may prevent me from gaining weight but I will never lose. This disease is absolutely exhausting, sometimes debilitating and I just don’t know where to go from here.

  20. Hi. My name is Patricia Lee. I was hospitalized in August 2019 with a near death experience and a misdiagnosis of ALS. I am, or was, a fit, healthy 57 year old. I started losing weight and suffered insomnia, high blood pressure, high heart rate, loss of muscle and soft tissue, severe anxiety, loss of strength in my legs, the list goes on and on. I chalked it up to the ALS. Turns out the doctors in the ER said the past year of symptoms were not due to ALS (did another MRI and found NO signs on brain scan of ALS scans were clear) the culprit was my Thyroid! It raised my blood pressure and heart rate and sugar levels, leaving me after an estimated year of my thyroid going bad as a type 2 diabetic with high blood pressure. I take insulin before every meal and time release insulin at night. ALSO Methimazole 3xs a day. In 5 months I have gone from 104lbs to 165lbs,my hair is falling out by the handfuls and I have no energy or desire to do ANYTHING! I have for the last two weeks started taking only 1 pill of Methimazole in the morning and not taking the other two doses. The prescription calls for 3 times a day. I only eat 2 times a day with NO sugar and low carbs. Yet I’m so swollen in my face and body my eyes don’t even open all the way they are so puffy! A little better since I reduced taking the Methimazole. Can this medicine cause the hair loss and severe weight gain? I don’t know what to do! My primary doctor doesn’t seem concerned since my A1C has gone from 9.6 to 6.5. So I am controlling my diabetes very well. But the rest of me is a mess and I’m so depressed. Do you have any suggestions for me to try and get back to feeling and looking normal! Any tests I should have done, blood or X-ray? They did a sonogram of my thyroid in ER and it was ok. I appreciate any advice you can give me. Also forgot to mention problems with my teeth. Lost fillings and 6 crowns, gum loss all in last 6 months. Is this thyroid related?

  21. About 7 months ago, I was diagnosed with Hyperthyroidism after losing significant weight. My TSH was only 0.002 and all the other Thyroid hormones high. I also had most of the other symptoms of Hyper. 3 weeks on 15 mgs of Methimazole got rid of my symptoms and got my weight back. Also all my hormones were at normal level
    After 3 months on 15 mgs , my endocrinologist instructed me to
    cut dosage to 10 mgs. That was December 23 f last year.
    In mid March , about 2.5 months after lowering dosage to 10 mgs I have started losing weight again no matter how much I eat. I have am losing muscle weigh fast and begining to look and weigh like I did 7 months ago when I was not on any medication.
    My lab work as of one week ago is normal. Why am I losing weight again despite being on 10 mgs Methimazole. I am frustrated. Should my dosage be adjusted back up to the previous 15 mg.


  22. I am under VA care. I have been given three dose increases based on blood tests with each dose change leading to increased weight each time. Currently dose is 10MG. Total weight gain from 219 lbs to 290 lbs in 4 months. My height is 6’1” which puts me in the morbid category. We all have a “sell by date” (I’m 64). So the question is; do I die from a heart attack caused by A-AFib and my hyperthyroidism or do I die due to congestive heart failure cause by the obesity thanks to the medication to treat hyperthyroidism? My endocrinologist is non-responsive to my calls of distress. Why do I do?

  23. Im reading this and just crying!!
    I do not want to live like this.
    I want to stop taking methimazole and whatever it will be – it will be .
    What this drug does to me – I can not accept. I rather be sick and die than live like this

    • Hello Anka, I’ve found myself on this site a few times, and I’m dismayed to discover that your despairing comment is the last one posted. Also that you have been left hanging for a month. This seems unfair on both you and anyone else who finds themselves here looking for stories of support and hope.

      I wanted to send you a positive note of solidarity. I hope you are getting help now, or at least getting a handle on things. I say this as a 50 year old woman who has been fanatical about body image for forty years. I’ve always been a runner. I’ve always been lean. The first week I started treatment I invested in some digital scales for the first time in my life. The creeping numbers have caused me no end of distress. Some might suggest I am torturing myself, I prefer to think of it as taking control. I’m six weeks into Grave’s treatment (40mg to start, reduced to 20mg now).

      Last summer before diagnosis I hit 55 kilos, I thought it was my new swimming regime! I started treatment in February at 58 kilos and I’m now 62 kilos. I was told to stop exercising for my heart, which sent me in to a tailspin. I haven’t fully completed the handbrake turn I need to do on my carefree calorie consumption yet. But I will. I also plan to do more weights instead of running.

      On my darkest days I feel that my body has turned on me, I feel betrayed by it. I feel it is punishment for my vanity over the years. On good days however I am able to rationalise that life has simply changed abruptly. It feels unfair, but it is not a cancer diagnosis. I consider myself lucky that my Grave’s was caught during a medical for a new driver’s licence. It turned out that I was dangerously unwell, my numbers were shocking. I had ignored the symptoms and chalked them down to peri-menopause. I was also relishing the unprecedented weight loss and hyperactivity. I thought it was my superpower. Turns out I’m only human after all.

      We moved to France from Ireland 18 months ago and due to Covid my language skills aren’t progressing. I’m navigating a new health and insurance system in a foreign language, which is adding to the challenge. But the internet can be a force for good, which is why I wanted to respond to you.
      Doctors, partners, will not understand or will attempt to diminish to distress that the side-effects of treatment cause women in particular. I also feel guilty about ruining meals for my husband. We love food, we love to cook and to eat. Our mealtimes were precious and rapacious. They are a lot less fun when I’m sitting in front of an apple or a poached egg when he has a platter of french meats and cheese and bread. I’m a lot less fun. But I have a responsibility to him also so I’m working on my attitude. He is trying to make changes to help me also. I won’t deny that left to my own devices I’d have a teaspoon of peas and a glass of wine for dinner. But that is not the solution. I need to hardwire in lifestyle changes, there is nothing else for it.

      Life is a gift, please find strategies to wrestle back control. I know I have a long journey ahead. But people have much worse to deal with so I am going to do what I can to mitigate the side effects. Life is worth living, even if it means lifestyle sacrifices. I hope you can find the strength to stand up to your diagnosis. Believe me, I know it is a daily uphill battle. But there are strategies, it’s not a done deal. The future is not written yet and you can take control over yours. All the best.

      • Margaret,
        Thank you for your post!! I’m turning 50 in July and like you, I’ve been a runner for years. I’ve always been a bit athletic, exercising, lifting weights, and staying fit and thin. Managed to stay pretty much the same size and weight for most of my life. In the past few weeks I have been diagnosed with Grave’s and like you, brushed off some symptoms that were telling of a problem. I had a physical for Grad school that revealed me to be hyperthyroid. I always prided myself for my fantastic muscular legs. If nothing else, I had great legs. In the past 6 months I noted a great deal of muscle wasting in my legs and arms. I was upset thinking my legs would NEVER look the way they do now. I now know that it’s due to my disease. I’ve been stressed and almost devastated reading about Methimazole that I now have to take. First flabby legs and arms and now I’m going to be overweight. YOU made a difference for me today! I read your post and you have inspired and motivated me to take control! You ARE superwoman!! I will be revamping my diet and fighting through some exercise to try to rebuild my muscles and prevent excessive weight gain. Thank you again for sharing your story! I’d love to keep in touch and know how things are going for you. Maybe share information that might help us? Good luck to all of us.

  24. Ok; I started methimazole 3 years ago and have noticed a significant increase in my falling asleep during the day and I am putting on weight with anxiety attacks, minimal sleeping at night and very hungry all the time which is not me. I am working all day as a speech pathologist, am awake at 5am and not laying down until 10pm. I am out like a light when I lay down like the switch was flipped but not feeling rested at all when I wake up. I am concerned for the weight gain and my body changes. I want to reduce my dosage again. I was started on 5mg 1x daily and couldn’t wake up. Was dropped to 2.5mg and that seemed to work until this year with the loss of 4 family members including my mom to COVID19, loss of 2 pets and adult children with significant sorrows that we try to support. Is there a better plan for me? I have my thyroid but it has 3 cysts in left neck and 1 was red hot when I started medication. I need my voice and my swallow as I am a singer in addition to being a therapist. I appreciate any feedback to assist me as I return to the endocrinologist this summer for my checkup. I have missed seeing the doctor for 18 months due to COVID19.

  25. Hi everyone! I was diagnosed with hyperthyroidism 8 years ago and been on methimazole since. I started with a very high dose because my symptoms and more importantly, my lab results were awful, slowly over time my dose has been reduced to 7.5mg daily. I DID also put on a lot of weight very fast, it was 7kg in two weeks, I’m very short, 1.50m, so 7kg DO show. I had to get rid of all of my clothes and buy new ones. I felt like a whale. But I don’t feel like that anymore. What has changed? My view on it. I should not and must not compare my current weight to an underweight sick version of myself. I weighed 44kg, I was very skinny, I loved it, I looked great, but I was also VERY sick. So no, even if that looked like my ideal weight, it wasn’t, that was my sick weight and I often have to remind this to myself because I do feel fat most of the time. I have also struggled with eating disorders on and off (which a lot of people call diet, but they’re disorders). A thing that works for me in feeling better is getting my regular check-ups. I don’t know about you, but I get my full thyroid bloodwork every 2 or 3 months and it can’t go wrong from there. In all these years my dose has been upped and lowered accordingly and that makes me feel in control. If you started methimazole overweight, that is most likely due to other lifestyle or health issues. But if you started underweight as I did, take your meds, get healthy, and love yourselves.

  26. I was diagnosed with GD in October of 2018. I was started on 40MG Methimazole daily which ended up WAY over-correcting and caused not only hypothyroid symptoms, but also a significant (25lb) weight gain in just 4 months. I was tapered to 20Mg daily and then 10mg daily and finally my numbers were improving so my endocrinologist continued to taper until I got to 2.5mg daily. I thought there was hope of remission but when I got down to 2.5mg daily my TSH was suddenly <0.02 again and I started having palpitations and losing hair again (unfortunately this time no weight loss). I’ve been on 5mg daily for the last 4 months and my numbers haven’t budged so I’m feeling discouraged that now I’m heading back to 10mg daily and gaining weight again.

    I have been doing intense hour long (Orange Theory) workouts 3-4xweek and eating better and the scale has not changed. We were hoping to start trying to have a baby next spring but since I can’t seem to get off of the methimazole and it causes birth defects I worry that that won’t be an option- plus it’s very difficult to get pregnant when your thyroid is not functioning properly. I’m turning 36 in March so the clock is ticking and I’m feeling very discouraged.

    As sad as I am to see so many people suffering from this, I’m glad to hear I am not alone. Hope you all have a Happy Holiday season.

  27. Reading this has left me completely hopeless – had my bloods done due to feeling under the weather – can back TSH 0.01 and T4 36. I’ve had no further contact from my gp but see I’ve been referred to the endo people. Having suffered on and off with eating disorders the weight gain is a considerable concern – I haven’t lost anything due to hyperthyroidism. I am keen not to be medicated as my symptoms are barely there. Desperate to get my big bike tour of Europe done then … I’m ready to die because the life that looks ahead is not one I want! At 42 it’s not been bad run

    • Tara,
      I’m right where you are. My husband and I have had serious conversations about quality of life. I feel FAR worse on the medication than I ever did even at my worst with hyperthyroidism. So many symptoms now that the drs just ignore because their only goal is to get some numbers on a piece of paper where they want them to be. Would I rather have 5 years of feeling like “myself” or 20 years feeling horrible? I have been on Methimazole for about 8 months now and am to the point where my entire body hurts and I can’t sleep because of the side effects it causes. I’ve gained over 20 lbs, none of my clothes fit and I’m depressed and at serious risk of an eating disorder if I’m not already considered there. I don’t want to leave the house. I feel horrible and disgusting. I have no clothes that fit. I’m starving myself to just try and slow the weight gain. All to try and qualify for surgery that might make me feel even worse and cause me to be on medication and feel this way for the rest of my life.
      I didn’t get the weight loss benefit of hyper until the very end when I had issues with a kidney stone (and that was probably due to not eating with the pain of the kidney stone passing) if anything being hyper made it difficult for me to lose weight. The dr keeps telling me how sick I am and I keep telling her that the treatment is making me feel far worse. It feels like a tug of war I can’t possibly win and I’m over it, the weight gain is just the last drop in the bucket for me. Like you said I’ve had 44 years, it’s been a good run.

  28. I’m late to this, but just found it since now I am being treated for hyperthyroidism with Methimazole. The only way I have found to lose weight is by starving myself every single day. I live on lettuce, yogurt, apples, tomatoes, and that sort of thing. I may be getting hungry a lot, but the idea of gaining weight terrifies me. I warned my doctor that I’ve had eating disorders in the past, and this has triggered it, but she was unconcerned. Therefore I’m not concerned either. At least I am losing weight instead of gaining. While I don’t recommend that everyone starve themselves, it’s the only option for me personally.

  29. I have been on 40 g methimazole since 2021 after being diagnosed with Graves Disease. I gained 60 pounds instantly in 1 year. Now I’m taking 5 gram and I can’t loss 1 pound. I’m a very active person I’m a fitness instructor and teach 3x a week in the afternoon and I also trained boxing in the morning 5x a week. I burned a lot of calories but I’m not losing weight I am still gaining. What else can I do to loose weight?

  30. I am a 78 year old female. I was diagnosed with Hyperthyroidism in 1990 and have been taking various dosages of Methimazole. I was taking 2.5 mg daily for quite a while and now I’m taking 5.0. I have had Graves disease for 1 year. My blood is tested 2-3 times a a year and I have 4 telephone appointments per year with my Endocrinologist. My next telephone appt is in 2 months and I have NOT been told to have another blood test, so this appt will be based on a blood test SIX months ago. My endocrinologist believes in Methimazole, and does NOT believe in diet, supplements, exercise/life style changes or that thyroid issues affect sleep or fatigue. She sent me to a sleep clinic to be tested for Sleep Apnea and I tested positive. However, the sleep doctor said to watch my blood pressure, and if it goes up I should consider used a CPAP machine. Four months ago (last blood test) my T3 Free was 8.36 and my T4 was 14.3. Whatever that means. I wear a device at night which monitors my Oxygen Desaturation Index and heart rate throughout the night. I take Selenium, L-Carnitine, Cold Liver Oil, Vit. B100, C, D, E, Rodiola Rosea, Maca, Matcha Tea, L-Thyrosine, Panthothetic acid, Ashwaghanda, Shisandra. Astralagas, several types of Ginsing, and some other supplements for osteoporosis, energy level and other things. The Ginsing is helping me enormously. I was on a Gluten free diet for three years, and am much happier now that I’ve quit it. When I was first on Methimazole, I gained weight, but recently I’ve been losing it very very slowly, about a pound every month or two.
    I drink some green tea and other herbal teas. My other issues include cataracts and Carpel Tunnel Syndrome. Other than that I am doing quite well, working nearly full time with no plans to retire anytime soon. Thank you for any advice.


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