Is Your Thyroid Destroying Your Gut Function?

Thyroid gland

If you’re struggling with constipation, diarrhea, or stomach pain… it may be related to your thyroid. In fact, your thyroid might be a root cause for your current health issues. It was for me.

My acne never seemed to go away even though I was doing everything right for years. And my energy wasn’t really all that robust. Not to mention every time I traveled I’d get constipated. It wasn’t until I fixed my thyroid that my skin got clear, energy really took off and the travel constipation stopped happening.

This is an example of how the body is a complex system and just focusing on the pain can lead to symptom management and never getting to the root cause of your problems. In today’s post, we’ll explore why anyone with gut issues should get their thyroid tested.

Why is the thyroid so important?

It’s a hormone factory responsible for two seriously important hormones that do a lot of heavy lifting in the body, like running your metabolism. Every single cell in your body has a need for thyroid hormone… and when things go wrong, your whole body takes a hit.

Is Leaky Gut Making You Sicker?


It starts with the metabolism…

Our Metabolism Isn’t as Complex as it Seems

Our human metabolism is made up of all the chemical reactions that take place inside your body:

  • Fat metabolism
  • Carbohydrate metabolism
  • Protein synthesis
  • Protein catabolism
  • Insulin secretion
  • Cognition and nervous system responses
  • And cardiac output

… just to name a few general ones.

Think of the metabolism as the cells in your body doing exactly what they need to do, when they need to do it. Depending on the location of these cells, certain jobs or reactions will be performed. Add up all of these reactions and this is your metabolism.

The cells in our bodies are told what to do by inputs from messengers. The messenger inputs that give cells directions are mostly hormones. So, if your hormones are either high or low, then problems begin to occur with the reactions inside the cells (metabolism). This cascades into symptoms we can actually feel. Particularly, too much or too little hormones are problems, because our cells will perform too many or too few reactions as signals are received.

Now, let’s get nerdy about Thyroid Hormones and the role they play with your gut.

How the Thyroid Gland Impacts Your Digestion

Remember too much thyroid hormone is just as bad as too little. When thyroid dysfunction is overactive it’s called hyperthyroidism. There is a common hyperthyroid autoimmune condition called Graves’ disease. When there isn’t enough thyroid hormone, it’s called hypothyroidism and the autoimmune condition is called Hashimoto’s thyroiditis. Either one of these scenarios affects the gut.

Much of what the studies focus on are constipation and diarrhea as a result of thyroid hormones affecting the following areas of the gut:

There have been many studies showing that those with thyroid dysfunction are prone to developing specific GI issues.

For instance, those with Grave’s disease were found to have 5 times the risk of developing Celiac disease and there are associations with Grave’s and Crohn’s. And IBD has been connected with patients with Hashimoto’s thyroiditis.

Having a happy thyroid is so crucial to having a happy body, because the thyroid makes and secretes the hormones responsible for all this metabolism/digestive stuff. Thyroid hormones help turn the cogs of the great machine, so to speak. But to understand the root of why thyroid hormones are low or high, we first need to talk about the 2 common ones:

The Thyroid Hormones T4 and T3, which affect nearly all parts of digestion.

Meet Your Friends T4 and T3 (and How Your Gut Health Influences Them)

The thyroid gland makes T4 in response to the brain sending it a chemical messenger called Thyroid Stimulating Hormone (TSH). But most cells in the body want T3, which means this whole process gets complicated fast. When I say thyroid hormones I’m speaking about T4 and T3:

  • T4 – Tetraiodothyronine aka Thyroxine (think inactive form)
  • T3 –  Triiodothyronine (think active form)

T3 and T4 are made from iodine (notice: tetraiodothyronine) and can’t be synthesized without it. Produced directly by the thyroid, these hormones enter the bloodstream and are able to talk to all kinds of cells and help direct them in their jobs.

So, say that the thyroid has just squirted out some of its hormones (I don’t know if it actually “squirts” but I imagine it that way), the majority of that hormone will be T4. This T4 actually gets converted into T3 in peripheral tissues. One of these peripheral tissues is THE GUT! As I mentioned above, T3 is the main hormone that the cells want and it’s easiest to think of T3 as the active thyroid hormone.

Many of the problems people have with thyroid hormones is in this conversion.

Conversion is Key

The conversion of T4 to T3 is not so simple; neither is the gut’s role in all of it. Conversion occurs in the kidneys, liver and gut, but it’s not just about what tissues are doing the converting. The health of the tissue and the enzymes involved in the conversion are vital. There are several enzymes, like Type I Iodothyronine 5’ deiodonase (5’-DI1), and micronutrients, like Selenium, that play a role in the process of converting T4 to T3.

Basically, there are a lot of steps in this process that could affect the amount of T3 produced. Scientists are still trying to uncover all of it, but they are finding that the gut may play a critical role in thyroid hormone regulation as well as in storing T3. And healthy gut flora have been found to assist in these T4 to T3 conversions, while bad bacteria have been shown to reduce plasma concentrations of thyroid hormones through endotoxin release.

To sum it up, a healthy gut and gut flora are important for converting T4 to T3 and to keep our cells happy and running properly.

Regardless of the health of your gut, if the rest of your body is producing too little or too much TSH, T4 or T3, then you might experience diarrhea or constipation.

Is Your Thyroid Causing Diarrhea or Constipation?

Diarrhea and constipation are typically never caused by one singular problem, so I’m not totally blaming the thyroid. What I am saying is if you’re someone who’s been eating SCD or Paleo, using lots of supplements and still seem to have motility issues then it could be because of your thyroid.

The research suggests that too much thyroid hormone (hyperthyroidism) in the body is linked more heavily to causing diarrhea. There could be several reasons for this diarrhea  including:

  • Fat malabsorption
  • Intestinal hypermotility
  • Hypersecretion of bile
  • Pancreatic enzymes and secretin in small intestine tissue
  • And increased intestinal transit time

This is basically saying that your digestive system is running on high and this super speedy processing results in wasted food and loose stools.

In contrast, constipation is typically found in conjunction with hypothyroidism. This is thought to be due to slower intestinal peristalsis, which is the movement of food and waste through our intestines. If the cells that control this have a lowered metabolism due to less hormone signals, the waves are slower and/or less powerful. However, there could be other culprits as this paper points out.

And lastly, this study shows 54% of people with a sluggish thyroid also had SIBO, which may suggest that we should always be looking at these two at the same time.

Always Look at the Thyroid and the Gut?

Beyond the study above, why might we always want to look at this duo together? Well, it comes back to how systems work.

When we look at how parts of systems talk to one another, we always want to find the feedback loops. In the body, these are pathways of signals that feedback to other areas. For instance, we’ve already mentioned in this article that thyroid hormones affect how the gut moves, but the gut can also give signals back to the thyroid.

The two “talk” back and forth through many signals such as the conversion of T4 to T3 in the gut, gut flora and levels of inflammation in the gut. Let’s say, for example, you’ve got a bunch of inflammation from a parasitic infection (which reduces nutrients), the conversion of T4 to T3 can go down. Also, higher levels of inflammation could change the output of TSH from the brain. Furthermore, the gut’s ability to digest and absorb critical nutrients, like the Iodine and Selenium necessary for proper thyroid hormone health, is very important.

It’s the old chicken or the egg scenario; which one came first? And anytime we face this problem, the best thing to do is assume nothing and test and address both at the same time. A big mistake happens when Hashimoto’s or Graves’ patients don’t also pay attention to their gut.

How to Fix Your Thyroid and Your Gut (at the Same Time)

Great practitioners will be thinking about testing and supporting both of these systems at the same time. Unfortunately, this isn’t the case for most of us (including me). Most of even my better practitioners ignored the gut-thyroid connection, and it was affecting me big time!

My energy wasn’t very reliable, my skin was still broken out and dry, and overall I didn’t really feel amazing. Of course, that was until I went into this area, which is why I think it pays to be in the know.

After all, you’re the CEO and ultimately responsible for your health.

If fact, if you understand how great practitioners attack this gut-thyroid connection you can actually guide your current doctor in doing so as well. It’s not always easy, but it’s very simple.

On our 2.5-hour gut-hormone presentation, I went into which thyroid tests are useful, optimal lab ranges that most great practitioners recommend and common treatment mistakes to avoid. Not to mention, I shared the exact step-by-step script and memory cheat I use with doctors. Because, let’s face it, who hasn’t gone into an appointment and forgotten what they were going to say?

Grab access to the gut-hormone presentation here:

– Steve


Steven Wright

About Steven Wright

Steve Wright is a health engineer and author. In 2009, he reached a breaking point when IBS took over his life and the doctors didn't know how to help. Since then, he has transformed his health and started to help others naturally heal stomach problems. You can check out his story here and find him on Google+, Facebook or Twitter.

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47 thoughts on “Is Your Thyroid Destroying Your Gut Function?

  1. Avatar

    I concur. Low thyroid activity also caused me decades of adult acne, chronic constipation, sleep issues, and much more. one doctor prescribes levothyroxine for me…not only did it NOT help the thyroid problem; but it gave me skull splitting headaches. Then I tried natural desiccated porcine thyroid. (NDT). The NDT apparently made my reverse T3 skyrocket (based on results of blood test). The only thing that made my hypothyroidism symptoms subside is pure T3.
    After I had a genetic test, it was discovered that I had multiple gene snp’s for primary hypothyroidism and for poor/low conversion of T4 to T3. My mother and older sister have had hypothyroid struggles their entire lives. In retrospect, I have had subclinical hypothyroidism since childhood. When all else fails, a gene test may reveal why typical thyroid therapies don’t work, for some people.
    Thsnks to decades of hypothyroidism, I have signs of SIBO, and very low stomach acid. At least now I know what to do about these issues!
    Thanks for listening.

  2. Avatar

    I had a nodule on my right thyroid discovered 1 1/2 years ago. It literally covers the entire right thyroid. Went in to get checked to see if it grew again. Thankfully, it had not. But they discovered one on my left side. Ive always had issues with my weight fluctuating up and down and acne. now with the growing of the nodule, ive noticed i cannot swallow as well. The acne got worse once i had my tubes tied and my insurance kicked me off of birth control. What natural remedies can i take for my thyroid to maybe balance this out a bit? My ent dr and my regular dr wont do anything about it. Help!

  3. Avatar

    I have been tested numerous times for hypothyroidism and always negative. I have severe digestive issues and lost 65 pounds in a few months. I just get too full and digestion is really slow. I’ve seen many doctors and was diagnosed with IBD and functional dyspepsia, but I am not convinced this is my issue. I have all the symptoms of hypothyroidism, I have lost my hair, skin is super dry, freezing all the time, and exhausted with terrible muscle pain. I haven’t worked in three years and my quality of like is low at times. I am wondering if anyone else has these issues and what your diagnosis is?

    • Avatar

      Hi Kim – Western medicine defines hypothyroidism a bit different than the functional medecine world. They typically just look as TSH, but there is more to the story. We’d suggest working with a functional medicine doctor to get tested with additional thyroid markers. They can also read the test for you and will be able to give you a better idea of what is really going on. the ones we suggest can be found here:

      • Avatar

        Hello my name is David I was wondering if I could get a few of you guy on my fb to give me some tips what to expect i have had thyroid problems since i was19 im39 now theve gotten worse my thyroid is very swollen, no energy, constipated dr. Has me on 50mg toproil to slow Hart rate 10mgs of methmazole but I fear Sergey need advice I’m a good person not crazy, my doctor says it mostly happens to wemon I can’t find many men to ask so i need you to please help (davidhodge hickory NC) on facebook

  4. Avatar

    I had my thyroid removed over 3 years ago. Things were going well until this past 8 months. I lost 30 pounds ( that’s not the bad news!) and now my THS has jumped to 4.8 and I have chronic diarrhea. My doctor is giving the meds three more months, but my guts are fighting me all day. Any light you can shine on the situation would be appreciated.

  5. Avatar

    Hi I’m Sarah I am actually suffering right now. I have done my research both my mom and sister have suffered with thyroid issues. I have all the systems and this article spoke to me the most bc I have had stomach issues for years thought I had issues to gluten and high fructose corn syrup and sucralose. Now I’m not so sure. The most and worst thing is I’m always so stinking exhausted and I feel like I could sleep all stinking day. I’m just curious is anybody going through the same issues ? I have an appt with a specialist this month

    • Avatar

      HI Sarah- sorry you’re feelign this way. Many, unfortunately, feel the same way and we’d encourage you to first start by healing your gut as described in the article. You may then want to work with a practitioner to get some testing done and work out a protocol to support your thyroid.

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    Hello everyone, Thanks to everyone who has shared their experience. I am here because I have not quite found what I am looking for. I was diagnosed with Graves 4 years ago. I took my medications & radiation therapy and it was just getting worse. Against my Dr’s advice, I changed my Diet a little and started an excersice routine. I was still very hungry and very tired, still I went from sleeping 12-16 hours a day with intermitten naps to sleeping only 10 hours. Fatigue is the worst. I then opted for a colon cleanse, enemas & turpentine/castor oil treatments. I feel a lot better. I have a lot more energy, do not require naps, my mood is far more stable, I do not have racing heart episodes anymore. I sleep 8 hours, no naps needed. My thyroid is not swollen, I can eat without regreting it later. Coffee, food, fruits sometimes water caused an incredible pain under my right rib. I do not get those anymore. However, I still have this bloating gut!! I look pregnant!! I have excersised rigorously and it’s still there. Could it be effects of leaky gut syndrome? My acne is the worst!!! I can’t clear it up with anything under the sun!! Could this be related to the fat deposits I can’t burn off? My Doctor had no response. My last tests came out negative for hyperthyroidism last check up. He said… “Keep doing what you’re doing”. I thought Graves decease was incurable.. I have some symptoms left, so I cant’t take the lab tests at face value. Don’t get me wrong, I hope it’s gone for good. Could I have been mis-diagnosed? Does anyone here have any experience with leaky gut syndrome or relatable conditions that may explain my belly and acne? Thanks for reading.

    • Avatar

      Thanks for your post. You have given us hope as my daughter has just been diagnosed with Graves disease. You can get help with leaky gut from a really good herbalist. There is a book written by Brendan Salmon that is very good for all kinds of issues too.

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      Many people online who have tried a low histamine diet say that has cleared up bloating. Maybe you could it up, and see if any of the symptoms for histamine intolerance match yours.

  7. Avatar

    Hi I suffer with a gastric stomach which gave me awful indigestion and heartburn. I’m on tables for it and has helped. But now and then I get heartburn. I’m also in the process of getting .your thyroid checked. A gastric stomach is inot the family. Is there anything I can do to help it at home. Plus would a gastric stomach be linked to my thyroid. Thanks

  8. Avatar

    I have SIbo and my digestion is ridiculous slow. My thyroid seems to be under control so I assume the digestion is all the Sibo. Already did two rounds of antibiotics and didn’t get rid of it. Any suggestions for improved digestion and movement? My constipation is so bad I don’t even feel the urge to go to the bathroom when I’m all full inside.

  9. Avatar

    I was diagnosed with thyroid issues back in 1999. I took levothyroxine for years, but recently switched to synthroid. After almost a year, we finally got my thyroid regulated. Recently I’ve been having stomach issues. My primary physician wouldn’t/couldn’t answer my questions, so I went to the Mayo Clinic. Still can’t get any answers! I understand this condition is hereditary, as my father and all of his sisters have had issues, and some of my brothers do, too. I just want answers, and to feel better!

  10. Avatar
    Starr Bustillos says:

    I have hypothyroidism. I was diagnosed April 2016. Since then I have had terrible stomach issues. I have a GI Dr. that has preformed numerous tests that have all come back normal. Through out this time my starting weight was 123lbs as of today my weight is 100.4. I have no appetite, severe abdominal pain, diarrhea and or constipation, and nausea. My blood work has also come back normal. Am I going crazy?

    • Avatar

      Hi Alice – it really depends how damaged your thyroid is. Most people whose damage to the thyroid is due to autoimmune disease (Graves or Hashimotos) cannot reverse the damage that has been done. They can prevent further damage from occurring through diet and lifestyle, and better manage their symptoms. Some people are able to reverse problems with the thyroid before it advances to the point of Hashis or Graves disease.

      Hang in there! Just because image has occurred doesn’t mean healing cannot occur.

  11. Avatar

    I was diagnosed with hypothyroidism in 2001 after complaining of huge mouth ulcers at the back of my throught and eating next to nothing and still gaining weight and always being tired. I also suffered from diarrhoea all my life. Whent to the doctor and did tests for that but they can never give me any answers. Its now years later and I still suffers from diarrhoea every single day, I am still tired. We can not seem to get my thyroid under control, it goes up and then down and up and down. In my country they only prescribe one of two meds for thyroid – eltroxin and euthyrox…I was on eltroxin for years but my medical aid said they dont cover it any more so now I am on euthyrox…. Dont now what to do anymore. My biggest problem is the diarrhoea….I just wish they can design a sort of testing devise like with sugar and high blood pressure where you can test the levels of your thyroid everyday and then use the correct dose…?

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    Engela Conradie says:

    I was diagnosed with hypotyroidism 4 years ago. Now all of a sudden my tests came back normal and they stopped my thyroid medication. Can it be. I am 60 years old and all of a sudden I get stomach problems like a sharp stitchy pain on right under ribs, nausea, and anxiety which is terrible.

    • Avatar

      I’ve recently been diagnosed with the same thing! My doctor told me that it can actually go into remission – especially if you’ve been treating it in some fashion. Not sure if this would be the case for you. Hope this helps!

  13. Avatar

    Every time I eat anything or drink anything my stomach boosts. My digestion has slowed down and my feet swell if I stand a lot. I was diagnosed 28th hypothyroidism five years ago. I was on Levonthyroxine but I stopped taking it because I moved a lot and didn’t have a Dr.
    I also gain weight like crazy and I’ve not done anything to cause it.

  14. Avatar

    After being on the candida diet for years I still get a vaginal itch /irritation after drinking water . PLEASE HELP . Am I over hydrated . The canfida is now at a very low level and my energy is back but I constantly battle with it . I know I have a sluggish thyroid as well. I read that eating more and drinking less will actually raise my body temperature

  15. Avatar

    Testing for thyroid is a dead end road most of the time with the test appearing to be normal but one has all the symptoms. In addition, all can be well in the blood but there is resistance at the receptor site. Most practitioners are unfamiliar with natural treatments for the thyroid and the meds they give rarely work. I am a nurse and can tell you it is very difficult to find treatment because these doctors just don’t have a lot of experience with alternative treatments

    • Avatar

      You are absolutely right Lisa, doctors hardly recommend any natural alternatives remedies as they have either no knowledge or their hand tied up. Can you please share your knowledge how to get Thyroid test done properly, also the effective alternatives ?
      Many thanks

    • Avatar
      Karen Puccio says:

      I recently have symptoms of hormonal imbalance hot flashes, head aches, nausea, no appetite, stomach gas. They are checking the thyroid, can the no appetite occasional loose stool be thyroid symptoms?

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