Why Synthroid isn’t Causing Weight Loss and How to Fix it

Are you on the thyroid medication Synthroid and not losing weight?

If so you aren't alone...

Synthroid is one of the most commonly prescribed medications for patients who have hypothyroidism but here's the problem:

Not everyone does well on this medication.

Their bodies don't absorb it, they don't convert T4 to T3 or they need more T3 due to other problems. 

​Despite this, almost every patient is given Synthroid, levothyroxine or other T4 medications and many of you are still dealing with weight issues. 

​And I want to share with you some reasons why that may be the case. 

It turns out that the thyroid is certainly involved in maintaining your metabolism and can lead to weight gain if you are hypothyroid - that much is true.

But did you know that simply replacing thyroid hormone in your body with medications like levothyroxine and Synthroid often isn't enough to help you lose weight?

In this post, I'm going to talk about the reasons why Synthroid isn't helping you with weight loss and what to do about it.

More...

Understanding Thyroid Function and Weight Gain vs Weight Loss

​This part can get confusing for many patients. 

Does hypothyroidism cause weight gain?

The answer is definitely yes, but why it causes weight gain is a little more complex.

Your thyroid helps to control and contribute to your resting metabolic rate (1) (AKA resting energy expenditure) otherwise known as metabolism.

Total T3 levels correlate with weight

Studies have shown that your basal metabolic rate is correlated with total T3 levels and therefore your ability to convert T4 to T3. 

​So when you have hypothyroidism or low thyroid hormone, your metabolism will suffer. 

Slow metabolism = weight gain

That's why one of the common side effects of hypothyroidism is ​low body temperature and cold hands/feet

As your metabolism slows you produce more energy which means you produce less heat.

Less heat = colder body temperatures = slow metabolism​

But that isn't the only ​way that hypothyroidism can cause weight gain. 

Believe it or not, your thyroid also influences other hormone systems in your body. 

Here's an example of what can happen to your hormones when you have hypothyroidism:

  • Progesterone levels may fall leading to estrogen dominance and weight gain in the hips, butt, and thighs (low progesterone may also contribute to infertility)
  • Cortisol levels increase causing weight gain in the abdomen
  • Insulin levels increase leading to abdominal fat 
  • Leptin levels may increase causing weight loss resistance
  • Testosterone levels may change as sex hormone binding globulin falls

So what happens is as thyroid hormone falls you get hit with a double whammy:

Hypothyroidism leads to a slowing of your metabolism and causes other hormone imbalances which then lead to further weight gain.

The big problem is that simply fixing your hypothyroidism by replacing thyroid hormone with Synthroid or levothyroxine does NOT fix the other hormone problems.

It may resolve your hypothyroid symptoms like hair loss, fatigue, and brain fog - but it usually doesn't lead to weight loss.

Why?

thyroid function on energy production

Because ​the other hormone problems still persist!

​But what about the weight gain from hypothyroidism itself? Does getting on medication help at least a little bit?

Yes, but not a lot.

If you are going to lose weight after getting on Synthroid or levothyroxine it will only be about 5-15 pounds at most.

That's because the thyroid usually only contributes that much to your total weight.

If you are 50+ pounds overweight then 15 pounds may be from your thyroid, 30 may be from insulin resistance, 10 may be from estrogen levels or cortisol levels, etc.

Weight gain and weight loss are much more complex than just eating less and exercising more and hoping that everything will "work itself out". 

​The bottom line?

If you are going to lose weight when you add Synthroid or levothyroxine it will only be a small amount IF the medication is right for you. 

What's more is that due to other mechanics in your body, the addition of T4 only medications like Synthroid and levothyroxine can actually lead to weight GAIN.

weight gain on levothyroxine

It may not make sense now, but we are going to discuss below how that happens.

Hint: it has to do with T4 to T3 conversion. ​

You can read more about how levothyroxine causes weight gain here. ​

Download my Free Resources:

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Does Synthroid Cause Weight Loss?

So the big question is this:

Does Synthroid actually cause weight loss?

The answer is that it CAN, but unfortunately for most patients, it most likely will NOT cause significant weight loss. 

Why?

In order to understand we need to talk about the basics of thyroid function. 

If you have a decent understanding of thyroid function feel free to skip this part, but if you are a beginner please pay close attention. 

First:

There are 3 forms of thyroid hormone floating around in your body...

  • T4 --> This is the reservoir form of thyroid hormone but is NOT active by itself. Synthroid and levothyroxine are T4 containing medications only - which means they are NOT active by themselves. T4 can either turn into T3 (which we want) or Reverse T3 (which we don't want) depending on the circumstances in the body. 
  • T3 --> This is the ACTIVE thyroid hormone in your body. NDT and Cytomel/Liothyronine are medications that contain either some T3 or all T3. Your body makes some T3 from the thyroid gland but most are converted from T4 hormone. 
  • Reverse T3 --> This is the INACTIVE thyroid metabolite in your body. This acts as a natural brake mechanism for your body in case you are experiencing illness, chronic inflammation or trauma. Your body will turn T4 into Reverse T3 if it needs or wants to put the brakes on your metabolism.

So when we are talking about Synthroid we have to remember that this medication contains only T4 thyroid hormone. 

That means by itself levothyroxine is essentially an inactive form of thyroid hormone (2), but it has the potential to become active if conditions are perfect.

So when your Doctor gives you Synthroid or levothyroxine he/she is making the assumption that your body will have no problem turning the T4 in Synthroid into the active T3 thyroid hormone in your body.

Now, this sounds good, except when you consider this:

If conditions are not perfect then your body is just as likely to convert that T4 hormone into the inactive metabolite reverse T3 (3) thereby making your thyroid function WORSE.

So what causes your body to convert T4 to T3 and T4 to reverse T3?

All of these factors increase T4 to reverse T3 conversion (exactly what you DON'T want):

S,o take a look at that list and ask yourself if you have any of those conditions? 

You probably have 2 or more if we are just going off of statistics here.

The point is this:

If you have any of those conditions and you're taking levothyroxine or Synthroid then there is a good chance you might be converting your T4 into reverse T3 instead of T3. 

​So let's put this into perspective...

If you're taking levothyroxine or Synthroid (T4 only medication) and your body is turning it into the antithyroid metabolite which can blunt thyroid function (5) it's possible for these medications to lead to weight GAIN instead of weight LOSS.

TSH levels and obesity

This isn't to say that it will have this effect in every person, because that's certainly not the case. 

In fact, most people do still need some T4 medication, the problem is that they also need pure T3 medication and most Doctors don't frequently prescribe T3 containing medications.

The amount of T3 that you need depends generally on how many chronic medical problems you have or how sick you are.

​The sicker the patient, the more T3 they generally need. 

If your plan is to take Synthroid or levothyroxine for weight loss and you aren't hypothyroid then you are most certainly out of luck. 

Because even if you have hypothyroidism it's NOT likely to cause significant weight loss by itself (6), except for certain circumstances. 

Studies have shown that even taking suppressive doses of LT4 (levothyroxine) to lower the TSH does NOT result in weight loss. 

But this study did show that lowering the TSH did slightly increase the basal metabolic rate of women, but not enough to normalize free T3 levels. 

​How Long Before Synthroid Helps with Weight Loss?

So why is it that some people are able to lose weight on Synthroid while other patients don't lose any weight and some very unlucky patients actually gain weight on it?

​The answer generally has to do with thyroid conversion (as we mentioned above) and some of that appears to be genetic, while the rest highly depends on other factors like that list above.

​But what about those lucky few people who do lose weight on Synthroid, how long does it take for this to happen?

Or maybe you just recently started taking the medication, how long should you expect to be on it before you start losing weight and/or feeling better?

If Synthroid is going to work for you, then two things have to happen:

1. You need to be actively converting T4 to T3 (If you know you aren't converting T4 to T3 you can learn more about how to increase this conversion process naturally here)

2. And you need to be on a high enough dose for your body (You can learn more about how to determine if your dose is adequate here)

​If both of these conditions are met then you should expect to notice an improvement in your symptoms within 4-8 weeks. 

It's a good sign if you noticed ANY improvement while taking Synthroid or levothyroxine even if you haven't lost any weight. 

It's a sign that your body both needs and can actually use the T4 medication. 

It doesn't necessarily mean you don't need T3 medication, but it's a sign that T4 is part of that equation. 

Weight loss after starting thyroid medication generally comes a little bit later. 

Before you lose weight you should be noticing some improvement in your symptoms, things like an increase in energy, a decrease in hair loss, a decrease in constipation, etc. 

If you've been on Synthroid or levothyroxine for months to years and you haven't noticed any difference then it isn't like you are going to lose weight by simply increasing your dose.

But let's say you are on a high enough dose and you are converting well enough and you still aren't losing weight...

What then?​

Synthroid vs NDT vs T3 for Weight Loss

If you didn't already know there are more medications for your thyroid than Synthroid or levothyroxine.

  • Natural Desiccated Thyroid (Armour thyroid, WP thyroid, Naturethroid) = T4 + T3 in about an 80/20 ratio (still contains more T4 than T3) 
  • Levothyroxine and Synthroid = T4 medication only (the inactive form of thyroid hormone)
  • Cytomel and Liothyronine = T3 hormone (the active form of thyroid hormone)

There are formulations of both T4 and T3 hormone that are porcine-derived known as Natural Desiccated thyroid

There is also a medication that contains T3 only (the active thyroid hormone) known as Cytomel or liothyronine.

​You've probably heard that these medications are "better" for thyroid patients. 

And there is certainly some truth to that statement, but it's more complicated than just saying one is better than the other.

In my experience, most patients do not do well on Synthroid, levothyroxine or other T4 only medications. 

But it's also not uncommon for me to see patients on high doses of NDT who still feel very poorly and still can't lose any weight. 

So, which of the thyroid medications is best for weight loss? 

​You obviously want to take whatever is best for YOUR body, but generally the more T3 in the thyroid medication the more effective it will be for weight loss. 

That doesn't mean it causes weight loss directly, instead, it's probably more related to the fact that your body is finally able to use the active thyroid hormone because you are no longer providing competition through reverse T3. 

The truth is if you're having issues with T4 medications then you will most likely need some form of active thyroid hormone (T3) to actually help you with weight loss.

So let's consider how to use these medications and under what circumstances...

Patients that do well on Synthroid and T4 only medications: ​

  • Patients who have never been on thyroid medications before
  • Patients who are extremely sensitive to T3 containing medications
  • Patients who are very sensitive to other medications and supplements
  • Patients who have no other chronic illnesses or medical conditions
  • Patients who have noticed weight loss or other improvements while on T4 medications within 4-8 weeks of taking the medication and are at an appropriate dose

Patients who do well on NDT and other forms of T4 + T3 combos: 

  • Patients who have never been on thyroid medication before
  • Patients with minor to moderate insulin and leptin resistance
  • Patients with 20-40 pounds to lose (not morbidly obese patients)
  • Patients with some chronic medical conditions
  • Patients who have failed T4 only medications like Synthroid or levothyroxine
  • Patients who are too sensitive to T3 only medication or have severe adrenal issues

Patients who do well on T3 only medications like Cytomel and Liothyronine: 

  • Patients with multiple chronic medical conditions
  • Patients with severe insulin resistance and leptin resistance
  • Patients with severe weight loss resistance or who are morbidly obese
  • Patients who have very high reverse T3 levels (> 30)
  • Patients who have failed T4 only medications
  • Patients who show some improvement on NDT but who did not experience weight loss or who are still symptomatic

How to make your Synthroid more Effective

Another alternative to switching thyroid medication is to take steps to increase the effectiveness of the Synthroid you are already taking. 

You can do this through 3 steps which I will outline below:

#1. Increase T4 to T3 conversion through supplements

You can increase T4 to T3 conversion by reducing inflammation, providing your body with both zinc and selenium and by taking certain nutrients. 

Nutrients like rosemary and guggul extract have been shown in studies to help naturally improve T4 to T3 conversion which may result in higher total T3 levels in people who take it. 

In addition, anti-oxidants, anti-inflammatory agents, and adaptogens such as Ashwagandha may also enhance thyroid conversion indirectly.

Lastly, improving gut function may also improve thyroid conversion as up to 20% of thyroid conversion takes place in the gut (you can do this by simply taking probiotics to reduce inflammation and enhance intestinal bacteria diversity).  

You can learn more about using supplements to increase peripheral thyroid conversion here

#2. Maximize thyroid hormone biosynthesis

Maximizing thyroid hormone biosynthesis refers to optimizing the amount of thyroid hormone that your body produces naturally. 

If you are suffering from Hashimoto's or certain nutrient deficiencies then the total amount of thyroid hormone produced by your thyroid gland may be limited. 

Normalizing thyroid hormone production may be the simplest way to increase and improve thyroid hormone status in your body. 

You can find a list of 10+ nutrients all required for proper thyroid hormone synthesis in this detailed post

#3. Increase cellular sensitivity to thyroid hormone

Finally, it's also important that you make use of the existing thyroid hormone floating around in your serum by enhancing its action at the cellular level. 

Both zinc and Vitamin A have been shown to improve thyroid cellular action and may be beneficial as a final step to improve the effectiveness of thyroid hormone replacement therapy. 

You can find my recommended supplement here which also is designed to improve T4 to T3 conversion as well as improving thyroid hormone sensitivity. 

These steps will allow you to take control of your health and improve your thyroid function without needing to alter your medication dose. 

This is particularly helpful if you can't switch thyroid medications or if your provider isn't willing to work with you. 

Recap + What to do Next

At the end of the day, it's important to realize that every single person is unique. 

That means what your body needs will likely be different than what other patients need even though you both have the same issue. 

Remember that Synthroid can certainly help some people with weight loss but losing weight with hypothyroidism isn't as simple as just getting on the right type or dose of medication. 

Due to a variety of reasons including high reverse T3 levels and poor thyroid conversion many patients don't do well on Synthroid. 

That means most of you probably won't be able to lose a significant amount of weight while on this T4 only medication. 

But it's not all bad news...

Many patients with hypothyroidism have been able to lose weight by taking the right approach (check out these case studies below for more info):

​Now it's your turn:

Are you on Synthroid or levothyroxine?

Have you lost any weight? Why or why not?

Leave your comments below!​

References (Click to Expand)

Dr. Westin Childs

Dr. Westin Childs is a Doctor of Osteopathic Medicine. He provides well-researched actionable information about hormone-related disorders and formulates supplements to treat these disorders.He is trained in Internal Medicine, Functional Medicine, and Integrative Medicine. His focus is on managing thyroid disorders, weight loss resistance, and other sex hormone imbalances.You can read more about his own personal journey here.

48 thoughts on “Why Synthroid isn’t Causing Weight Loss and How to Fix it”

  1. I am on synthriod. I had my thyroidectomy in February. Before I had my thyroid out I had lost 70 pounds with exercise and diet now I have put on 30 pounds and the scale won’t stop going up. No mater what I do. I’m in tears all that work I did and i can’t stop the weight. I have been reading all of dr Westin child’s info. I feel if I take this to my dr he might not do as I ask !

  2. I am currently taking levothyroxine synthroid medication. Before I was diagnosed with Hashimotos, I gained about 20 pounds very quickly even though I was eating healthy and exercising. My TSH level was at 5.5 at that time, where I was seeing a family medicine doctor. After being on 50MCG levothyroxone, I did not change my diet at all and was still eating bread and carbs, so I did not immediately lose weight but I stopped gaining weight like I used to. So recently I have been seeing a naturopathic, practioner, who put me on a detox diet with no gluten or dairy and I lost about 15 pounds. I am still 20 pounds overweight , and by seeing an endocrinologist for the first time he prescribed to be a higher dose of levothyroxone at 75 mcg, he did take a look at my labs and saw that my TSE 3.0 which is still higher than optimal. He also looked at glucose levels at 90 while fasting And looked at my hemoglobin a1c, of 5.3 and said there no reason why I shouldn’t be losing weight . Now I’m trying to figure out if I should go ahead and take the higher dose of levothyroxine, because right now my weight loss has slowed and I’m at a plateu. This doctor is very conventional, and was not willing to worth with me.

  3. At age 33 I became hypohyroid after a missed miscariage
    I’ve been on synthroid for 20 years current dose 125 and on cytomel 5mcg I’m female 53 yrs old, post menopausal, highly stressed and weigh 173 at 5.1 height & insulin resistant with bouts of hypoglycemia and prediabetic

    I’m currently on wkly vitamin D, 50,000 iu, on wellbutrin for the blues and phentermine for weight loss but only lost a few lbs of water I’m tired have trouble sleeping brain fog if I work or do anything of significance I have to sleep for hours not an option

    I’m a mother of 3 kds (14,12,8) I feel like I function at less than half capacity

    My endocrinologist is very flexible with me on trying different things but nothing works I get lab work every 4 to 6 months

    Weight loss is an impossibility

    Your post helped me understand why I am in this state but I don’t know what more I could try I want so much to improve my health so I can finally enjoy life
    Not sure you can offer advise but at least for your information I’d say you are on the right track it may be too late for me to get better but hopefully you can find solutions for others

    Becky

  4. I have been on synthroid since 2009. In 2013 I lost 20 pounds. I was on 125 Mcg, but in 2014 my dose was lowered to 25 Mcg, ever since I haven’t been able to lose weight, I have been gaining and becoming very depressed.

    • Hey Rhonda,

      Thyroid dosing can certainly impact your ability to lose weight. If you haven’t already you may want to seek out a new provider more willing to work with you.

  5. Hello Doctor,

    i am unable to lose weight from the past 2 yrs.. no weight gain…just that i am stuck at the same weight and same inches for past 2yrs… at 75kgs…i was taking levothyroxine…i went to an endocrinologist in july & he subscribed nature throid 1/2 grain ( 32.5mg) …. i lost 2 kgs in the first two weeks of taking it…… n now again after taking it for 3 months m stuck at 73…i have increased the dosage taking 1.5 grain in morning & 1 grain in mid afternoon….. my antibodies are at 172…GF DF egg free….cortisol.progesterone.. estrogen all at desired levels… TSH at 0.8…. free T3 at 4.1

    i have also done 4:3 fasting where i took bone broth on fasting days…. i look thinner than what i was…but it feels like my water retention has reduced…. but absolute no change in weight & inches…. i do HIIT & moderate strength training… very lil abdominal fat… more on obliques & thighs

    its really frustrating to give it all & still not see results….. i am lost & dont know what more can i do to see the weight budge… i stay in UK

  6. I tried levothyroxine and broke out in a terrible rash, my doctor then put me on synthroid. So far I don’t think I am having any problems. I have Waldenstrom’s Macroglobulinemia, am on watch and wait but am taking a station drug and can hardly stand up or get out of a chair.
    My weight has gone up over 40 pounds in a year and I ache all over, is there any help.
    I have blood work done quite often is there anything I should be looking at on my numbers besides IGa, IgG and IgM.

  7. I have have low thyroid symptoms but bloodwork has always come out okay. My doctor went ahead and prescribed synthroid to see if it would help with symptoms. It seem to help, but I have been struggling to lose weight. He thinks it is due to my age, 49, but I wondering if it is because of the synthroid. I’m not going to know if it working with bloodwork right? Since it didn’t determine the need for synthroid. I think I am estrogen dominate also. Any advice on what I should do?
    Thanks!

    • Hey Rhonda,

      The single best thing you can do is find someone to help guide you (another physician or provider who understands hormones). Primary care doctors aren’t trained to deal with hormones and they just aren’t very good at it, so don’t waste your time seeing them for this purpose.

  8. I was only diagnosed 2 weeks ago. My doctor had checked back in August. My TSH was 4.98, T4 was 1.4. She said it was ok because my T4 was in the normal range. She decided to recheck 2 weeks ago to see if my TSH had gone back to normal on its own. I asked if she could check my cholesterol just for the heck of it, not knowing it had anything to do with thyroid, or any connection. They just say check cholesterol before and after starting a new nutrition plan. My TSH went up to 7.8, T4 went down to 1.0 and triglycerides were 448, so no reading for bad cholesterol because triglycerides were too high. Good cholesterol was below normal at 34. She said this was caused by my thyroid and diagnosed me with hypothyroidism. I took 50mcg of levothyroxine for a week. It made me very sick. I asked her if she’d be willing to let me try WP Thyroid or Nature-Throid. She said no because people’s bodies normally convert T4 to T3, with T3 containing meds they end up getting too much T3. She called me in a new prescription for brand name Synthroid today and hopes I’ll do better with that than the generic levothyroxine and retest me in 6 weeks. Thing is, she’s unwilling to even check my T3, or anything other than TSH and T4. I had all kinds of abnormal labs she doesn’t feel are worth following up on. My fasting blood glucose was 121 and she said it’s fine because it’s not high enough to indicate diabetes. She never followed up, nor did she recommend any dietary changes. Just treated it as if it’s normal. Meanwhile, I feel like I sound like a hypochondriac because I’m concerned about the lack of follow up on abnormal tests. This article recommends meds that will help us, but what can we do when our doctors are unwilling to try? Or in my case, even check out T3 to see if it’s possible we need it?

    • Hey Nikki,

      There are many options you can take as a patient to try and improve your thyroid hormone conversion and production through various means (I have articles about these subjects), but if these fail then you will likely need to seek out a new physician who is more willing to work with you with testing, medication, etc.

  9. Hi, my name is Chelsea and I’m 28 years old. I’ve been taking Levothyroxine for the past 2 years and have gained 50 pounds despite watching what I eat and exercising. In all honesty, I think a part of me has given up on ever losing the weight, which is really crummy because I’m 5’3″ and morbidly obese; I used to be at healthy weight, bouncing back and forth between 140-155 up until my early 20s. Over the last 7 years, I’ve gained over 150 pounds, and while I know my hypothyroidism isn’t the complete cause, it certainly isn’t helping.

    My cousin was recently diagnosed with hypothyroidism (it runs in both sides of my family) and her doctor suggested nature throid for her rather than just T4 like what I’m taking. I have an appointment with my own doctor tomorrow and plan on insisting on bloodwork, including:

    • full blood panel
    • hormone and insulin levels
    • fasting blood work
    • THS (as of last June it was 2.87)
    • Free T4
    • Free T3
    • Reverse T3
    • Thyroid Peroxidase Antibodies (TPO)
    • Thyroxine Binding Globulin (TBG)
    • Vitamin D
    • Vitamin B12
    • Magnesium
    • Zinc
    • Iodine
    • Iron
    • TgAb (Antithyoglobulin Antibody)

    Before my appointment, I planned on insisting my doctor switch me over to nature thryoid, but, the more I read your blogs, the more I realize that may not be enough, that there could more additional imbalances I didn’t realize may be caused of a poorly functioning thyroid. Do you think adding a T3 medication only to my levothyroxine would be more beneficial than just switching over to nature throid?

    I’m so tired of living my life this way – morbidly obese, exhausted in the afternoons, and still be sluggish; something has to change, but I’m not knowledgeable enough to know what to ask for. What do you suggest?

    • Hey Chelsea,

      There isn’t an easy way to answer that question because each person is different, because of this you really need to see someone who understands what I discuss here if you actually want to get help. Changing your thyroid medication is a good first step, but it’s just one of many.

      In addition you will likely be met with some resistance getting those tests simply because I doubt your doctor is used to ordering those tests (and some you included above are urinary not serum).

  10. Which type of specialist is best for treating hypothyroidism? Endocrinologist? My primary care doctor just keeps upping my dose of synthroid and I had no idea there were other types of medications available. I think it’s time to see a specialist. Thank you for your very educational article.

  11. Diagnosed with Graves disease in 2008 after thyroid storm, then it leveled itself out after 3 months, now two months ago after a 30 lb weight gain for no reason, exhausted beyond words, anxiety depression.. TSH was indeed increased, started levothyroxine 6 weeks now.. Zero weight loss.. Fit in nothing still pretty tired I don’t leave home due to the depression from weight gain. This is consuming my life. I hate this I won’t eat anything if I can’t get this off.. I can’t stand how I look now for no fault of my own. Please tell me what to do

  12. Hello Dr Childs I have had Graves disease for almost 26 years now and I’m only 45. I have always watched what I ate and stayed very active. But in the last year I have gained a lost of weight despite all efforts not to. I have read your articles about T4 causing weight gain and tookiy to my Dr who without hesitation put me on Cytomel 25gm along w/ my synthroid. 125mh but I am still unable to lose weight. She did do blood work to see where my levels where at and my t4 was low, tsh high, and my t3 was very high because ING on the 6. Something range. Can you plz help me figure out what mg of each I need to lose weight. Carrying all the extra weight is really hard on my joints and ability to exercise.

    • Hi Gracie,

      Your thyroid is only part of the problem when it comes to your weight. You may also have other issues that are contributing to your inability to lose weight, other hormones like insulin and leptin. You will need to be assessed for these hormones in addition to making changes to your thyroid dosing.

  13. I am 46 and have been on synthroid for about 3 months now 25mcg and i have gained 10 lbs pretty much all in the belly. I am constantly hungry. I eat all day. Not just snack but eat. My levels are all normal now except iron is still somewhat low but coming up. I dont want to keep gaining weight. I thought i would lose even 5 lbs. I am kinda put out about this and would rather not take it. I did better with weight when i wasn’t taking it.

    • Hi Kellie,

      It’s unlikely that a low dose of synthroid (25mcg) would result in either weight loss or weight gain. Going off of it depends largely on why it was started in the first place.

  14. Hello,
    I am 28. A year ago the left side of my thyroid was removed. I have been on Syntroid for a year. I gained 30 pounds. I eat healthy. I just wonder what medication would be right for me in order to lose weight?

  15. Hi,
    Recently had blood work done and she did the basic thyroid test but I insisted at least do the free t4. According to the doctor guidelines it is within range but on the very low normal range. My research shows it’s actually below the doctor guidelines. She said there is no cause for concern. And I’m telling her she has no idea how I feel and the fact that I cannot lose weight. Heaviest I’ve ever been at 270lbs. 🙁
    I’m 51 years old and it doesn’t look good that I am going to lose 100lbs as I would like to. Suggestions please?

  16. I had my thyroid removed a year ago. I have tried numerous medications but the side effects are horrible. Iam beginning to think I’m drug sensitive because I feel horrible. I’m on synthroid now and my whole body hurts, no energy,fatigue, hair loss, weight gain, brain fog, sleeplessness , tremors and the list goes on. This is not what you call quality of life. Help!!

  17. Hi,
    I had my thyroid removed Feb. 12th, 2016.. I had been having hypothyroid issues for 2-3 years and had my doctor test me several times over a 2 year period, but he kept saying all my tests were fine and nothing was wrong.. after 2 years of this and symptoms not being relieved, I advised him I wanted to see a Endo.. my thyroid had been swollen for months but because the test were fine.. he said there was nothing to worry about.. I told him he did not have a choice, I wanted a reference for the Endo.. he stated they would have to do a ultrasound to which I told him fine, do it… they contacted me the week after Christmas 2015 and said I had a large tumor and I needed a biopsy… wow, I was floored.. and mad as hell… I did the biopsy, it came back inconclusive with Hurthle cell.. my endo wanted to leave it in but I refused.. my surgeon was awesome.. did the surgery on a Friday, went home on Saturday.. Monday he called me.. it was cancer… my issue now, is after being on the synthroid for over a year and telling my doctor that I was still really tired… it was the same thing all over again.. tests are fine.. with no increase in meds.. I had to pay for another doctor to test me to tell me that my body was not making T3.. I took the info to my doctor.. at which point he drew more blood, then contacted me to tell me my levels were low… my point for sharing is that you should ALWAYS get another doctors opinion and if you are not happy with your doctor.. push them..it is your body and you know how you feel.. you are paying them.. they work for you… this article was very helpful as I am having problems losing weight.. at this point tho, please confirm if I am correct reading this.. that I should try to up the dosage of my T3 meds, to get the weight loss started.. I also found out I have high cortisol levels and insulin resistance.. what do I do about that??

  18. I am on levothyroxin for about five weeks. I am 50+ pounds overweight. Much of this I have put on in the last three years. Since taking this medicine, I have stopped putting on weight but have not list any. Will see my Dr. Next week and ask him to up the dosage. But I am on heart meds so he has started me on a very low. Dose.

  19. Was on Synthroid for many years. Finally asked my Doctor to let me try Armour it keep my level good. But my weight is been a struggle and now Im type 2 Diabetic. Not on med for this been trying to control it with watching my carb in take. I’m also deficient in Vitamin D.

  20. Hello, thank you for the information. I was curious what falls under “anti-seizure medications” that is stalling weight loss. I am specifically wondering is lamotrogine is one of them that falls into this category.

  21. I was diagnosed with Graves disease in 2003. Since then I have been on name brand Synthroid 100mcg. Everything was controlled until this past year. I have gained 15 pounds in 1.5 years, my TSH was high (4.5) and the dr. increased my Synthroid to 125mcg about 6 months ago. The weight gain has increased to about 1 lb per month. I have changed my diet and nothing helps. I am going back to the dr. tomorrow but he only tests T4 and TSH.

  22. Hi! I have just recently been diagnosed hypothyroid. I️ have been battling hyperprolactenemia for the past 7 years. I am on Cabergoline and Levothyroxine. What do you think would be the best way to lose weight? Is there a correlation between these issues and my weight gain?

  23. A few facts about me:
    I was diagnosed with ER/PR+ breast cancer in 2011 at th age of 34. I was vitamin d deficient then.

    I recently sued my doctor to run thyroid check and vitamin d check as I have been experiencing bone pain and fatigue. Here are my numbers:

    Free T4 .76
    TSH .59
    Vitamin D 14

    What do you suggest?

  24. I have been on Synthroid, Levothyroxine and now Levoxyl for over 35+ years. I am 57 years old and have noticed weight gain of 30-40 lbs. in the last 5-10 years. I have an appt. with my doctor this week and I’m so happy to have read your articles now. I am currently on 150 mcg of Levoxyl and my dosages have varied from 125-200 mcg in the last few years. I am frustrated with not being able to lose weight and have noticed extreme tiredness. I’m hoping my doctor is open to adding T3 to my Levoxyl, as according to your articles, it seems like my T4 is being converted into Reverse T3 instead.

    I will keep you posted- thank you!
    Beth

  25. I’m on synthroid 175 mg and i have gain so much weight I’m 249 and keep gaining so I’m fina stop taking it POINT BLANK PERIOD

    • Hi Vannette,

      I don’t have a post on how to treat Graves’ disease but I will add it to my list! Thanks for the idea.

  26. Hi I am Miami Graves disease patient, post radiation, which means I killed my thyroid. I have successfully been on Synthroid for 8 years , I previously was on Levothyroxine for 2 years and my body then rejected the medicine. I’m now having what I think is the T3 reversal reaction and they have up my Synthroid from 112 to 125 micrograms. Over the past year I have gained 20 lbs and lost so much hair, I no longer feel like myself, the feelings of my original symptoms have returned very fatigued getting sick easily really feel terrible most all the time…. as I read these articles I didn’t find much on side effects or negative results of a T3 hormone could you elaborate more the benefits and negativities of what it means to switch from Synthroid to a T3 supplement. Or do you use this along side of the Synthroid ? In the past my thoughts have been that this is alarming and not a good sign.

    Thank you for your time.

    A concerned 46 year old Synthroid rejecting woman.

  27. Hello
    I had thyroid cancer in 2010 I had my thyroid removed and am currently taking 175 mcg. Of Sythroid.
    I have had a struggle with all of the wonderful stuff that goes on with thyroid disease. My worst problems are that I am breaking out in rashes food allergies/ sensitive I have stopped eating dairy and soy but feel that I am allergic to acacia or fillers in the synthroid medication. I itch all over my sleep is horrible. I have a hard time getting to sleep/ staying asleep weight is awful It’s almost impossible for me to lose weight even with proper diet and exercise. One of my biggest questions is it seems like ever year I have a mental break down I get nervous and anxiety the Dr’s have tried me on several different anxity depression medications however I don’t seem to be able to tolerate any of these medications. I am going to see if my endocrinologist will put me on a tirosint Armour,Unithroid,or Levothroid. I take my medicine about an hour before I get up in the morning.I get brain fog forgetfulness and about once a year it’s almost like I have dementia or Alzheimer’s that can last a week till a couple months. And then I will be normal again. It’s scary and I feel like I spend alot of time worrying about the next time this will happen again. I just recently started to realize that it must be the thyroid medication that’s been doing this to me. I blamed it on other medications in the past. You would think that the Dr.”s would have told me this but I never was told I shouldn’t drink dairy,soy among other things. I am so scared and frustrated
    With all of this. Might I add that alot of the time it feels like I get to much of the medication in my system all at once.
    I am 45 years old. I had thyroid cancer 9years ago and never had any mental break downs before the cancer. So please I could use some advice! Thank you for your article and time.

    Sincerely,
    Roxanne

  28. Been having similar problems as other women in relation to weight gain on levothyroxin. Started on 25mg then upped to 50. My tsh is now in normal range after 2 months of meds. Ordered selenium to see if this supplement can help with weight gain.

    Exercise is usually around 2.5hrs per week and calorie intake is not high-3 square meals. Snacking on fruit.

    Any other changes I should be making. Have gained over 10lbs since start of meds in late November. Thnx

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