Synthroid and Weight Gain: What Users Say

• Doe...
• Taken for 1 to 2 years
• January 3, 2020

For Hashimoto's disease "This stuff is just awful! I’ve had my TSH go as high as 52.0 (wasn’t aware it was that out of control) and felt better than I do now on years of treatment on brand name Synthroid! Endocrinologist just doesn’t seem to agree? And now I have a whole new set of symptoms such as itchiness all over, horrible anxiety, headaches, weight gain, the list goes on and on, and nothing new has been added to my daily routine, I know it’s this medication, I hate it. Just throwing this out there for anyone else so that you know you're not crazy! Good luck!"

• Paw...
• Taken for 2 to 5 years
• April 18, 2018

For Hashimoto's disease "Had my thyroid removed 2 years ago. Was put on Synthroid and have felt terrible ever since. Weight gain, joint and muscle pain, blurred vision, tremors, hair loss, constipation, irregular heartbeat, stomach problems, and the list goes on. Doctor tells me my numbers are fine, and I should be put on an antidepressant. Really. That's because they don't know enough about thyroid disease and keep pushing the drugs. This drug is next to poison, but no one listens to us. We are held hostage to these doctors that don't care. Where do we turn to because we are suffering. Help!"

• hap...
• October 14, 2011

For Hypothyroidism, After Thyroid Removal "I've had my thyroid removed 10 months ago, and I started taking the lowest dose of Levothyroxine (generic) six weeks after the surgery. I had my blood work done and dosage adjusted every six weeks until I ended up at 137 mcg daily, 5 months after the surgery. Then I switched to Synthroid brand. All this adjusting was done by an endocrinologist. I feel great, definitely much better than before the surgery when I suffered from severe hyperthyroidism. I did gain some weight right after the surgery, but once the dosage was correct, I was able to lose the pounds easily. All of my other symptoms (hair loss, abnormal sweating, fatigue) were gone once the dosage was correct. The right dosage is extremely important."

• Ann...
• Taken for 2 to 5 years
• May 2, 2018

For Underactive Thyroid "I was taking Synthroid for three years. I was extremely ill during that time and it worsened. I could not eat, walk without falling, gained 30 pounds, and my numbers did not go down. Finally, my endocrinologist agreed to put me on Armour Thyroid medication. I lost all the weight I had gained in two weeks, could eat, and walk. My whole life changed dramatically. Doctors are giving Armour a bad name, but I can tell you from my experience, it changed my life."

• Anonymous
• March 17, 2020

For Hashimoto's disease "Synthroid is terrible, it gave me an exacerbation of mental health symptoms! Nervousness, restlessness, anxiety, fatigue, constant dark thoughts, and depression. My TSH dropped from 0.50 to 0.02, and still no symptoms of hyper, just the same symptoms of hypo: weight gain, tiredness, and depression. I thought I was losing my mind! Trying to adjust my psych meds, thinking that was the issue, didn't work because it was the levo causing the problem. It's difficult to separate symptoms of mental health problems from thyroid problems because they can be similar. I got a referral from my PCP to see an endocrinologist. They switched me to Armour. Significant improvement. Levothyroxine stinks! I'd rather take no thyroid medication and suffer the consequences than take Levothyroxine."

• Deb...
• January 7, 2014

For Hypothyroidism, After Thyroid Removal "I had my thyroid irradiated in 2005 due to Graves' disease caused by Hep C treatment (Ribavirin & Interferon). At first, I saw an endocrinologist that prescribed Armour Thyroid, but loss of job and insurance forced me to go to a free clinic, where I received Synthroid. The clinic doesn't seem to understand the difference between experiencing low thyroid levels from naturally occurring hypothyroidism and complete loss of thyroid. My NP says to me, incredulously, 'You take an awful lot of thyroid!', and at that time, I was only taking 75mcg a day. Finally, after three years of 75 to 100mcg, when I felt absolutely crazy (tired, confused, hair loss, cranky, paranoid, angry, enormous weight gain), she now has me on 150mcg which seems not perfect but better."

• Peb...
• Taken for 5 to 10 years
• October 25, 2019

For Underactive Thyroid "I do not notice any difference with the medicine. I’m still suffering from depression, and I have extreme hair loss and weight gain even if I don’t eat more than 1500 calories a day: high protein, low carbs."

• Str...
• Taken for 10 years or more
• August 1, 2015

For Underactive Thyroid "Since being diagnosed with hypothyroidism in 1999. First, I was given antidepressants for being tired and gaining weight (eyeroll). I have been on 88mcg of Synthroid daily. My blood work has always come back with my TSH at the high end of normal. Former doctor retired years ago, so no continuum of care (walk-in clinic). Recently, a new doctor suggested we adjust meds to bring down the TSH level. Started with 100mcg of Levothyroxine 5 days & Synthroid 88 - 2 days a week. In a few months' time, I suffered some pretty severe side effects - extreme dizziness/weakness, lack of energy, mood extremes, weight is either climbing or stagnant, racing pulse/heart rate. We checked levels, and now TSH reads at the extreme low end of normal. I'm scared, please help."

• Miz...
• October 27, 2014

For Underactive Thyroid "Had partial thyroid removal with benign tumor 30+ years ago, was OK until about 2 years ago and routine bloodwork showed low thyroid. After 2 years being OK on the medication, suddenly the thyroid levels are dropping again, hair falling out, skin is breaking out in itchy red welts, gaining weight, so Dr. upped the dosage. A couple of weeks on a higher dose I feel like I am 'wired' in high gear, can't sit still, talking to myself going in circles, and my hot flashes have really, really ramped up big time. Dr. says to give it at least 60, preferably 90 days to adjust, not sure I can hold out that long before stopping it. Hoping there is a better solution out there someplace."

• Anonymous
• August 21, 2012

For Hashimoto's disease "I have been on Synthroid now for 4 years. I wasn't able to take the generic Levothyroxine because it caused me high blood pressure. I was shocked to find out I had thyroid disease. My dosage continues to go up, I'm on 125 mcg now, and just had my TSH checked, and it's again on the low end (which I can tell because of fatigue, weight gain, hair loss). I demand my thyroid to be tested every 4 months. When it's in the middle of the 'normal' range is the only time I feel good!"

• Thi...
• Taken for less than 1 month
• April 25, 2017

For Underactive Thyroid "After seeing my OB for some problems with menstruation, I was sent for about 10 different blood tests to check my hormone levels. Let's just say that we found the source of my problem and I was referred to an endocrinologist. She wanted to repeat my TSH level because she said that being at 3.65 was a little high for someone my age. So I went back within 4 weeks to get retested and my TSH was 10.36, and I was feeling it. I was so tired I could barely get out of bed. My headaches were out of control, and I gained about 10 lbs in a month's time. I just started 75 mg Synthroid a few days ago, so I'm feeling optimistic. I feel once we get my pituitary adenoma, thyroid, and my vitamin D under control, I'll be so much better. ADVICE: listen to your body."

• Bat...
• January 3, 2018

For Underactive Thyroid "Thyroidectomy after cancer diagnosis, and so far I've had not had great luck with Synthroid. Currently, I'm on 112 mcg, and it makes me feel like I have an itchy sunburn. The weight gain is insane, I feel waterlogged in my legs most of the time and have too many mental glitches. I dislike this drug, it has too many fillers that cause other issues. If you have known allergies, avoid Synthroid until they can create an allergy-free version."

• Que...
• February 17, 2017

For Hypothyroidism, After Thyroid Removal "I was diagnosed with papillary thyroid cancer and had a total thyroidectomy and also lost one parathyroid. The doctor used high levels of iodine during my surgery, and my endocrinologist had to put me on an iodine-free diet for four months to clear it from my body. During this time, I wasn't allowed to take any thyroid meds at all. I spent that entire time in bed under an electric blanket turned on high during a Vegas summer. Nothing normal there. I was a zombie. I had to have help to use the bathroom, shower, and everything, I was so weak. After RAI, I started Synthroid. A few months later, I noticed small improvements but gained 50 pounds within the first year. It's been seven years now, and I'm worse all the time. I've lost my life to this. I'm switching to Armour."

• Pga...
• Taken for 6 months to 1 year
• January 14, 2022

For Hashimoto's disease "Like many, I was doing amazing on Nature Throid until about 2017, and since then I have bounced from no medication and from Tirosint and Synthroid. Synthroid has been the worst decision of my life! I feel so sad and depressed, which probably has to do with a 40 lb weight gain after switching to synthetic meds. I truly wished this worked for me!"

• Not...
• July 20, 2021

For Hypothyroidism, After Thyroid Removal "I had a thyroidectomy, and I'm on Synthroid. This medicine just doesn't work like they told me it would. It doesn't work! My nails are falling off and ripping more easily. My hair, which was always so beautiful and long, is looking like a dollar store mop. It has breakage really bad, and it's so thin and just yucky. Also, gained 70 pounds."

• tmi...
• April 9, 2015

For Hypothyroidism, After Thyroid Removal "I had a goiter in my teens that was treated with radioactive iodine. I've been on Synthroid for almost ten years, having trouble finding the right dose. I was on 125 mcg for a few years, but my TSH jumped around a lot. Last time I checked, it was around 30, so not good. I decided to try 150 mcg. At first, I had a bit of insomnia, but otherwise, I felt great. Going to find out on Saturday if it's been working as good as I thought. I ran out 3 days ago, and I've already gained a bit of weight (looks like I'm bloated) and woke up this morning depressed. Oh well, I get more on Saturday."

• Anonymous
• June 24, 2010

For Underactive Thyroid "I have been taking this for 6 months now. Before these medicines, I had problems gaining weight. Now that I am on this medicine, I can't stop eating. I have gained 20 lbs. When I stop taking these medicines, I am not hungry all the time. I also have high blood pressure. Not sure if the combination of the medicines has anything to do with the weight gain."

• Vin...
• Taken for 1 to 6 months
• June 6, 2016

For Hypothyroidism, After Thyroid Removal "I had my thyroid out in Feb. of 2016. I was put on 125 mg of generic Synthroid. My blood sugar was dropping below 50 on a daily basis. I looked the problem up on the internet and found that people had the same problem and advocated that I take the brand-name drug to correct the problem. For the past two months, I have been on the name brand, and I seem to be leveling out in the high 60s with my sugar, which is okay. I am stuck paying the extra charge not covered by my insurance, roughly $32 per month for 30 pills. Have had no weight gain yet, which I am very happy about. I am going to ask my doctor at the end of this month to increase my dosage to bring my sugar up into the 80s or even 90s where it belongs."

• fir...
• Taken for 2 to 5 years
• October 2, 2016

For Hypothyroidism, After Thyroid Removal "I was 1st diagnosed with hyperparathyroidism. The doctor said it wasn't bad to just watch it. After a couple of years, it got worse - I saw another doctor, and he did 6 biopsies - found that I had papillary cancer. Following month, I had my thyroid and 2 parathyroids removed. The surgeon put me on 100 mcg of generic Synthroid - seemed to be doing okay until I had the RAI, twice, then everything messed up. I was still having hair loss, ears ringing, teeth getting bad, bathroom habits were never the same, cramps, affected my salivary glands permanently, so I'm dry all the time. Plus, I've put on 25 lbs. I eat, I don't eat, it doesn't matter, the weight will not come off. The endocrinologist changed my dosage to 112 mcg, and I seemed to be doing better. I am back to 100 mcg with previous symptoms."

• Anonymous
• January 28, 2023

For Underactive Thyroid "I was on Synthroid for four weeks after I had a prothrombin time (PT) test. I didn't notice much change until week four, and I developed pretty severe heart palpitations that I'm still getting on and off. My anxiety increased, and I had brain fog, bloating, and weight gain. I have been off of it for a week, and my numbers are double what they were prior to starting it."

• Anonymous
• November 12, 2009

For Hypothyroidism, After Thyroid Removal "I had my thyroid removed six weeks ago. I have been taking this medication, and have experienced weight gain, depression, and anxiety. I have not felt like myself at all."

• vin...
• April 4, 2009

"Synthroid was horrible. I had severe fatigue, hair loss, dry skin, constipation, weight gain, high blood pressure, and high cholesterol while taking it."

• Rob...
• February 28, 2011

For Hypothyroidism, After Thyroid Removal "For the past three months, I experienced weight gain even though I run 5k five days a week. I feel tired and lack energy."

• Anonymous
• July 6, 2011

For Hypothyroidism, After Thyroid Removal "I have been on Synthroid since 2006. I have had significant weight gain and can't get rid of it. This medicine has helped with the cold chills and irritability."