Methimazole and Weight Gain: What Users Say

• Hol...
• Taken for 1 to 2 years
• October 9, 2020

For Hyperthyroidism "I have been on methimazole for hypothyroidism and Graves' disease for one year now. I have noticed side effects like extreme hair loss, bloating, constipation, upset stomach, fatigue, joint pain, and weight gain. I'm almost in remission now and can't wait to get off methimazole. I have also started seeing a naturopathic doctor and I'm absolutely amazed at the natural health benefits of food for hypothyroidism, I would highly recommend a naturopathic doctor to anyone"

• Sun...
• Taken for 1 to 6 months
• January 22, 2020

For Hyperthyroidism "I had a thyroid storm about 3-4 months ago and did the RAI 3X a day during my stay in the ICU along with methimazole 30mg a day and metoprolol 50mg a day. Immediately I did not have any side effects. Within a month or 2, the extreme Charley horses, numbness, shooting nerve pains, extreme tiredness, and sleeping all day came. My hair is brittle and thinning, and hair loss everywhere. My face got swollen chubby, periods got longer and heavier. Weight gain was very fast and I'm unsure of how to shed even one pound. On a positive note, none of my hyperthyroidism symptoms have returned. However, I don't know how to balance this out to avoid these pains, weight gain, and tiredness and maintain a healthy thyroid. Has anyone had this?"

• Bro...
• Taken for 1 to 6 months
• January 9, 2021

For Hyperthyroidism "I was diagnosed with hyperthyroidism in August 2020 and was put on 20 mg of methimazole. Within 1.5 weeks, I gained a whopping 10 lbs. My doctor reduced my dosage to 10 mg, and my weight, heart palpitations, and sleepless nights slowly went away. I'm still having dry eyes, a little eye bulging in one eye accompanied by it being wider than the other, and blurred vision that I’m seeing an ophthalmologist for now. Now I'm dealing with little red bumps and the feeling like something is always biting me. I always think a bug is crawling on me, and I am itching all the time. I scratch so much that I actually end up with tiny sores, mostly on my arms. I just did my blood work on January 5, 2021, and was informed today that my levels are still low. I'm going to a new endocrinologist next week to see if we can get this under control ASAP. I’m tired of it all and I’m tired of going to so many doctors all the time. I want my life back!!!!"

• Joh...
• Taken for 1 to 2 years
• May 20, 2020

For Hyperthyroidism "It works well to bring thyroid levels and antibodies down, but man, you will throw weight on like crazy. I cut my calories down by 30% and was still putting it on. Also seems to make me hold onto water (bloat) more."

• sur...
• October 13, 2020

For Hyperthyroidism "In June 2020, I was diagnosed with hyperthyroidism due to heart palpitations. After a blood test, I was referred to an endocrinologist. Initial test readings were T4 31.6 and T3 11.6. Started 10 mg methimazole a day and 40 mg propranolol for palpitations. My second test showed methimazole 15 mg a day and propranolol stayed the same. I started to feel short periods of being dizzy to longer periods of dizziness. T4 shows 18 and T3 8. My third blood test showed T4 12 and T3 at 6, all normal levels. TSH level 0.01 now lower dosage back to 10 mg a day, and no more propranolol. My heart rate is now 65 to 75 bpm, no palpitations. Been told by doc TSH 0.01 will be back to normal in weeks (range 0.045 to 4.5). I gained some weight too... In conclusion, I felt propranolol saved my life with heart palpitations, methimazole brought my T4 and T3 levels way down to normal range. T4 normal levels (9.0 to 26), current 12.1, T3 normal levels (4.0 to 11), current 6.0, TSH normal level (0.045 to 4.5), current 0.001 low will see later. Greetings from Canada."

• Dee...
• Taken for less than 1 month
• July 3, 2019

For Hyperthyroidism "I was prescribed a low dose to treat hyperthyroidism. My T4 and T3 were normal, but TSH was 0.01. After one month, I stopped taking it. Horrible back and joint pain, my hands are numb, constant headache, and weight gain. Can’t recommend this medication."

• haw...
• Taken for 1 to 2 years
• September 22, 2013

For Hyperthyroidism "I was diagnosed with hyperthyroidism two years ago, and an endocrinologist suggested Methimazole. I started on a lower dose and went in for blood work every three months. After about one year of tapering the medication, I was taken off. The only side effect I noticed was the weight gain and some very heavy menstrual bleeding, which has since resolved. I still have the extra weight, but I no longer suffer from palpitations and tremors. This medicine worked well for me, and I'm awaiting my tests to see if my thyroid function is still normal."

• Kir...
• Taken for 1 to 2 years
• March 30, 2022

For Hyperthyroidism "I’ve been on methimazole for a year after being diagnosed with hyperthyroidism and Graves’ disease. I felt terrible before the diagnosis. Could not sleep, exhausted, gained weight, could not focus or enjoy my life or work efficiently. About a month after starting 5 mg/day, I felt so much better. A few months later, I dropped to 2.5 mg per day and have been at that ever since. I am not in remission, but my thyroid levels are normal, and I can sleep, have energy, can work, and enjoy life. For those who say they’ve gained weight, I have not. I’ve been dieting normally and lost approximately 50 lbs while on the medication. Not an issue to lose weight for me."

• Ton...
• Taken for 1 to 6 months
• June 4, 2019

For Hyperthyroidism "I have been on this med for a month now. It has thinned out my hair and made me gain weight. I have never had a weight issue in my life. I have pain in my muscles and tooth sensitivity. I feel tired all the time. I can't wait to get off this med."

• Get...
• Taken for 1 to 6 months
• June 14, 2019

For Hyperthyroidism "I was on this medication for 2 months. I gained 30 pounds in 2 months. Brittle, broken, damaged hair loss. I stopped taking the medication after I got a liver scan, my liver is fatty, and my doctor said I have the liver of an obese person. I would not recommend this medication to anyone unless you want to be morbidly obese."

• dru...
• March 18, 2023

For Hyperthyroidism "It was a terrible experience for me. I developed thyroiditis following a severe cold, which in turn damaged my heart. I was subsequently diagnosed with hyperthyroidism and was told that I had Graves' disease, Hashimoto's disease, two worrisome nodules, thyroiditis, and another condition. The medical professionals suggested various treatment options, including drinking an iodine cocktail, undergoing laser surgery on the nodules, possibly having my thyroid removed, and taking medication. Interestingly, they initially believed that my hyperthyroidism was caused by a long-standing iodine supplement that I had been taking. However, it turned out that the cause was actually virus-induced hyperthyroidism with four insignificant nodules. I was prescribed a 10 mg dose of medication, but I experienced adverse reactions and promptly informed my doctor that I would be reducing the dosage. A few days later, I informed my doctor that I had stopped taking the medication altogether, as I was experiencing constant heart racing, elevated blood pressure, daily headaches, dizziness, weight gain, shortness of breath, and other symptoms. Prior to this, my heart rate had been too slow. As the patient, I believe that my doctor is working for me and should therefore focus on identifying the root cause of my condition."

• Anonymous
• September 3, 2016

For Hyperthyroidism "I was put on methimazole 10 mg late May. Within a month, I had gained 10 lbs, my finger and feet became swollen, pressure headaches that would not go away after taking Advil, it hurt just to walk, back pains, and I was soooooooo tired. I complained to my doctor and she lowered the dosage to 5 mg, and then she took me off of it after my levels were okay. Then last week, I've had to go back on it again, but I've noticed that my symptoms aren't that severe this time, but I'm still continuing to gain weight. My doctor says I need to be on it and try to have my hyperthyroidism go into remission. I hate this drug! I've never felt this bad in my entire life, but I have no choice but to be on it."

• CC ...
• Taken for 1 to 6 months
• July 7, 2016

For Hyperthyroidism "After 2 weeks of taking this medication, I began an extreme itch all over my neck and body. This itch lasted about 3 weeks. Then, severe back pain for 1 week. Weight gain. And extremely dry mouth and hair. Had to discontinue use. This medication scared me."

• Jrs...
• Taken for 1 to 6 months
• June 26, 2020

For Hyperthyroidism "This is now my second attempt at taking methimazole as I thought I was in remission - but wasn't. I am currently on 5 mg. The stomach pain is terrible and so sporadic. I am hoarse in the voice and can't jog anymore due to being out of breath. I am tall and lean and not overweight. I have begun to put weight back since starting the medicine 6 weeks ago. I am getting weird, red bumps on my skin. I am coming off of this medicine and looking into other options. I cannot do the stomach pain anymore."

• Spa...
• Taken for 1 to 2 years
• May 24, 2019

For Hyperthyroidism "My hands were trembling, and leg muscles were weak, hair loss and 62 lbs lost. I was diagnosed with Graves. I started a low dose of methimazole 5 mg and kept doing labs, increasing 5 more mg at a time. I am now at a 30 mg dose, which my doctor considers a high dose and thinks it’s time to radiate the thyroid as I’m not in remission. Side effects were itching, slight nausea, joints aching all over instead of usual arthritic hands. Immediate and continuous weight gain every time I increase the dose. Feeling kind of lazy and sleepy. My labs are all normal, but I’m getting a goiter-like thing in my neck. But it’s been 2 years, so I will take the radioactive meds and switch to thyroid hormones. Would be interested in knowing how the radioactive swallow works out for others. Did side effects cease? They say there are no side effects after the radiation, whereas with the methimazole, you can have liver and kidney damage over too long a period."

• Kat...
• Taken for 1 to 2 years
• July 9, 2021

For Hyperthyroidism "I had Graves' disease 25 years ago, and now again. This time, heart palpitations, shaking, hot all the time, lost 18 lbs in one month, sleepless nights. Started on 5 mg methimazole once a day. Immediately I started feeling better. I had hair loss, weight gain, depression, fatigue, and muscle pain. I have been on it for just over 1 year. For the past 4 months, my T3 and T4 have been normal, however, my TSH has dropped to 0.05. When I was taking 2.5 mg, my TSH was 0.30. I have now developed an eczema-type rash on 1 elbow, 1 knee, and on my toe. I think it is too much methimazole, but the doctor feels differently. I am supposed to be taking 5 mg, however, I am only taking 2.5 mg and have noticed my skin getting better. I am also a smoker, and I have found out that smoking can cause Graves' disease. 25 years ago, I was on methimazole for 8 months and quit smoking, Graves went into remission. Trying to quit again. Good luck to all with this disease."

• Ama...
• Taken for 1 to 2 years
• March 15, 2019

For Hyperthyroidism "I got diagnosed with Graves' disease almost 2 years ago and was prescribed methimazole. Within the first month, I gained 10 lbs and overall 30 lbs. Previously, I maintained my weight and didn't change my diet. When the doctor had me at 20 mg, I had severe charley horses to the point where I couldn't move. When she lowered the dose, it went away. I am taking 15 mg currently, and aside from it being difficult to lose weight, it is fine. I am no longer experiencing shaking, foggy brain, or any other symptoms I had with hyperthyroidism. If you watch what you eat and exercise more than usual, I think you would be able to combat some weight gain. I, however, kept things the same, and the decrease in my metabolism really hit. If you experience severe muscle pain/charley horses, consult your doctor because it is probably the methimazole. I took calcium in between my appointments to aid with the pain."

• KCJ...
• Taken for less than 1 month
• November 27, 2022

For Hyperthyroidism "I have been taking methimazole for almost 2 weeks, 30 mg a day. Day 7, this medication made me so nauseous till I would throw up. My doctor told me I could split the doses up to help with the nausea. I now take 10 mg 3 times a day, and the nausea has gone away. I have been weighing myself because the doctor says the meds can cause weight gain, but I haven’t gained any. I had horrible night sweats and rapid heartbeat, and both have almost ceased. I do have a little more energy, but I find I’m more irritable. I get my first blood drawn in a few weeks, so hopefully things are stable. My TSH was .01, T3 12.8, T4 4.14, so I was definitely hyper."

• sur...
• January 7, 2021

For Hyperthyroidism "This is an update on my hyperthyroidism. I'm at the beginning of month 6. I'm taking 10 mg a day now, but I started with 30 mg. With my treatment, my side effects started at month 4 with being dizzy all day and feeling like gastro. I started having a lot of gas, and my stomach makes weird noises. I did all the tests twice, he said, I saw all your results and all is good, then you have to wait until we finish the treatment. It may be the meds. Finally, the nausea is gone, but I still feel my stomach weird sometimes and also some tingling. Also, a few days ago, I got some red bumps, an allergy on my right arm, but very mild and is almost going away. About the weight gain, I got 20 pounds, but I started to get back to normal once they lowered the meds. No more water retention. Just to finish, I ask you to put the time when your side effects started, because in the pharmacy, they said the side effects are at the beginning of treatment, but I doubt it. So that's why I put the time frame, so we can all compare. Cheers."

• Tra...
• Taken for 2 to 5 years
• February 3, 2019

For Hyperthyroidism "I have been taking this medicine every day since July 2016. I have Graves’ disease. I have gained 15 lbs in 2.5 years. I have heavy periods now that last more than 8 days. My hair is thin, my skin looks like rubbish, and my joints on my hands and feet hurt. I also have brain fog now. I hate this medicine, but I take it every day to avoid radioactive iodine. Really not simple solutions for people like me who have Graves’ disease."

• Eli...
• Taken for 1 to 6 months
• November 5, 2018

For Hyperthyroidism "I do not like methimazole. I have been on it for 6 months, and my labs came back normal only one out of the six months. I was still told by the doctor to keep taking it. This drug has been very hard on my teeth, and I can't stand the weight gain and hair loss. I'm not having my thyroid removed or radioactive iodine stuff at this time, and also I'm being told hyperthyroidism is sending me into early menopause. So I am having my battles with the disease as well as the side effects from the methimazole. If you can avoid it, do not STRESS!!"

• Tal...
• Taken for 6 months to 1 year
• April 7, 2020

For Hyperthyroidism "I got prescribed methimazole for Graves' disease. Took the medication like I was supposed to, and everything seems to be fine except for some side effects, which are hair loss, weight gain, and sweating. But I do wonder if there is another medication they could put me on so I could lose more weight."

• DD5...
• Taken for 1 to 6 months
• December 6, 2022

For Hyperthyroidism "I’ve been recently diagnosed with Graves’ disease last year and have been on different doses of methimazole. 15 mg sent me into hypothyroidism, so now I’m on 10 mg. I have gained weight and feel some mental heaviness too. I’m getting blood work once a month to find a healthy balance of this medication to my thyroid functions. Fingers crossed :)"

• Anonymous
• Taken for 2 to 5 years
• September 8, 2021

For Hyperthyroidism "I've had hyperthyroidism for 4 years and went into remission. Now it came back. I lost so much weight and was feeling so sick without medication. Truthfully, I didn't want to get fat again. The last time I gained 15 pounds, it was horrible to lose, but the pills helped it go away. Now it's back. I felt so sick I took myself to my endocrinologist, and she put me back on again. It's been 2 weeks, and I'm starting to feel better. No more stomach symptoms anymore. It sucks to gain weight, but my heart palpitations have lessened, and I'm feeling normal again."

• Flo...
• Taken for 6 months to 1 year
• March 25, 2025

For Hyperthyroidism "Started on 5 mg and slowly increased to 15 mg. Six months in, I’m heading toward remission and back down to 5 mg. It has made me gain weight that I cannot seem to lose and causes me a lot of fatigue. I’m ready to be off of it, but it’s doing its job, and I didn’t have to kill my thyroid with radioactive iodine."