Cold Intolerance and Hypothyroidism Explained (Plus how to treat it)

Cold Intolerance and Hypothyroidism – The Connection Explained

Cold Intolerance and your Thyroid

One of the most common symptoms of low thyroid function is that of cold intolerance. 

And there are literally millions of patients who suffer from cold intolerance. 

It may not be the most 'sexy' symptom to complain about if you have low thyroid function, I would save that for something like hair loss or weight gain which are much more difficult to treat compared to cold intolerance but it's a very important early warning sign that something is off with your thyroid!

And it should, therefore, not be ignored. 

So while we are going to primarily focus on hypothyroidism as a cause of cold intolerance you should also be aware that other conditions can cause this symptom. 

And that's really the best way to think about cold intolerance, as a symptom. 

By itself, it doesn't necessarily mean something but it gives you important information about how well your body can produce energy, how much blood flow is circulating to your tissues, how well your mitochondria are working, and other information about your blood vessels. 

Why are we focusing on cold intolerance in the setting of low thyroid function?

Because it's the most common cause of this particular symptom and if you have cold intolerance it's the first thing you should look for. 

If you find that you don't have low thyroid function then you can always go looking at the other causes but I recommend starting with an evaluation of your thyroid first

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The 'Positive Sock Sign' as a Hypothyroid Symptom

I think one of the most telling symptoms of low thyroid function (also termed hypothyroidism) is that of the positive sock sign. 

What is a positive sock sign you ask?

It's a little test I use to determine if someone has low thyroid function and it goes something like this...

Do you wear socks to bed at night because you can't stand how cold your feet get at night? Even in the summer?

If the answer to this question is yes then YOU have a positive sock sign. 

And, so far, I've never met anyone who had a positive sock sign who didn't have low thyroid function. 

In fact, I consider this test to be so sensitive that I will often treat patients who have a positive sock sign before getting their labs back to prove that they really do have low thyroid function. 

Why is that?

Because it's absolutely NOT normal for you to have cold hands and feet, especially in the summer when the ambient temperature is higher than comfortable room temperature! 

Your body comes equipped with enough feedback loops and systems in place to help your body regulate your own temperature!

If you are not regulating your own temperature then we automatically know that there is something wrong with at least one or more of these feedback loops. 

And since your thyroid is the primary source of temperature regulation (1) (more on that below) it's the first place to look. 

What Causes Cold Intolerance?

We've gone this far and we haven't actually defined what cold intolerance is so let's take a second to do that and then we will jump into what actually causes it. 

Cold intolerance is simply defined as a sensation of you (the individual) being intolerant to cold temperatures. 

You might ask yourself:

Isn't it normal for me to be intolerant to cold temperatures?

And the answer is yes, but people with cold intolerance as a symptom experience this symptom when NO ONE else is. 

For instance:

It would be considered normal to have cold intolerance if you are outside and the temperature is 40 degrees or less. 

It would NOT be considered normal to have cold intolerance if you are outside and the temperature is 80 degrees or higher. 

And those people who have cold intolerance, as many of you reading this probably do, may experience intolerance at even higher temperatures. 

So cold intolerance is really defined as the inability to handle cold temperatures when other people can. 

I should also point out that those people who have cold intolerance tend to get very irritable and angry when exposed to cold temperatures. 

This is probably because of the impact that cold temperatures have on the body when your body can't regulate its temperature. 

But what actually causes this symptom of cold intolerance?

It really stems from a failure of the systems your body has in place to regulate your own body temperature. 

And pretty much all of this regulation (well, at least 60% of it) stems from your thyroid gland. 

The remainder stems from hypothalamic function or the function of your brain. 

But back to the thyroid for a second. 

Your thyroid helps control your body temperature by regulating energy production in your cells, by regulating heat production in your body, and by regulating mitochondrial energy production. 

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You probably already intuitively understand how this works even if this is your first time hearing about this. 

Anything in your body that produces energy will produce heat. 

You can create your own heat by simply rubbing your hands together. 

You are using energy to move the muscles in your hands and arms which produces heat and the friction created from rubbing them together creates even more heat. 

As long as your cells produce enough energy (through mitochondria) your body should have sufficient heat in basically every cell in your body. 

Some heat makes it to your extremities through your blood (which carries heat throughout your body) but most of the energy in your extremities comes from cellular function. 

If your thyroid isn't working properly then the following things will happen:

So, if you have cold intolerance related to your thyroid this is what is happening to your cells/body. 

Treating and Managing Cold Intolerance

As annoying as cold intolerance is, it's actually really easy to treat and manage. 

In fact, you really shouldn't accept anything but complete resolution of your cold intolerance as an outcome. 

Because, if you don't completely remove the symptom then you can say for sure that your problem has not been sufficiently treated. 

And we know this because of how cold intolerance and thyroid function are related. 

Cold intolerance stems from low thyroid function. 

And it's possible to completely normalize thyroid function with the use of certain prescription medications (or through natural routes if that is your preference). 

Treating cold intolerance as a symptom is really that easy. 

Fix your thyroid and you will fix your cold intolerance. 

As easy as it sounds, though, it tends to be slightly more difficult in the real world. 

Much of the reason that so many thyroid patients continue to suffer from hypothyroid symptoms, including cold intolerance, is that many thyroid patients remain undertreated despite taking thyroid medication. 

The good news is that you can use some of your symptoms, especially cold intolerance, as a barometer to determine whether or not you are on the right treatment. 

By focusing on your body temperature, in addition to your thyroid labs, you can tweak your thyroid medication enough to completely reverse your symptoms. 

But let me make one thing clear:

If you continue to have cold intolerance despite taking thyroid medications such as levothyroxine or Synthroid then you are most likely not getting ENOUGH medication or you are taking the wrong type of medication

I should also add that if you have cold intolerance you should ALWAYS be tested for low thyroid function because of the relationship that they have with one another. 

Properly Testing your Thyroid if you have Cold Intolerance

What should you do if you have the symptom of cold intolerance?

Pretty much no matter what you need to get your thyroid tested. 

This includes those people who have KNOWN thyroid problems and who are already taking thyroid medication and it also includes people who only have cold intolerance and no known diagnosis of hypothyroidism. 

The key here is to get the RIGHT thyroid lab tests

The standard thyroid lab tests that doctors tend to order will usually not be sufficient to catch early hypothyroidism. 

And this is important because cold intolerance tends to be an EARLY symptom of low thyroid function. 

Many people with cold intolerance who have early hypothyroidism will not show up on standard thyroid lab tests but they will show up if you get the expanded panel. 

You'll want to get these tests:

Most doctors will only look at the TSH when they are trying to diagnose low thyroid function. 

But, as I stated, the TSH only starts to show up once your disease is moderately advanced. 

For early diagnosis, you need to pay closer attention to your free T3 and reverse T3 levels. 

People with early hypothyroidism will see their free T3 lower and their reverse T3 rise and this marker show up before the TSH starts to rise. 

Final Thoughts

Cold intolerance is probably one of the more obnoxious and annoying symptoms associated with low thyroid function. 

It gives you valuable insight as to how well your thyroid is working both in your cells and in your peripheral tissues. 

Those people who have low thyroid function AND cold intolerance should be evaluated with an expanded thyroid lab panel to see if their thyroid is being undertreated (or to see if they should start taking thyroid medication). 

If you have cold intolerance AND you are already taking thyroid medication then you should have your dose adjusted, most likely in an upward direction. 

It is possible for you to completely eliminate the symptom of cold intolerance provided you completely restore your thyroid function back to its normal state. 

Now I want to hear from you:

Are you suffering from cold intolerance?

Have you seen any improvement in your symptoms by taking thyroid medication?

Are you still experiencing cold intolerance even though you are taking thyroid medication?

Do you think your cold intolerance is caused by your thyroid or some other issue?

Leave your questions or comments below! 

References (Click to Expand)

cold intolerance and your thyroid - what causes it

Dr. Westin Childs

About Dr. Westin Childs

Hey! I'm Westin Childs D.O. (former Osteopathic Physician). I don't practice medicine anymore and instead specialize in helping people like YOU who have thyroid problems, hormone imbalances, and weight loss resistance. I love to write and share what I've learned over the years. I also happen to formulate the best supplements on the market (well, at least in my opinion!) and I'm proud to say that over 45,000+ people have used them over the last 4.5 years. You can read more about my own personal health journey and why I am so passionate about what I do here.

49 thoughts on “Cold Intolerance and Hypothyroidism – The Connection Explained”

    • Hi Misty,

      I target them more towards adults. Technically, 17 years old is not yet an adult but I would touch base with your doctor because there’s a high chance they would be safe at that age.

      • Hi Dr. Childs,

        I have had hashimotos for most of my life. I am on a very high dose of levothyroxine and still I feel the cold all the way to my bone and I am miserable when I am outside and there is even a slight breeze but winter months are unbearable for me because it’s a bone chilling kind of cold. I can’t get my weight down, I started about 3 weeks ago your Hashimotos bundle, what else do I need to do?

        • Hi Cami,

          I would give the bundle at least another 3 weeks. It can take up to 6 full weeks for the thyroid to be influenced by changes in medications or supplements, so time is definitely a factor here. In addition, you’d want to order your free T3/total T3 lab tests the next time you get tested to see where they fall.

    • Hi Doctor,
      I have here results of my FT3-6.24 pmol/L FT4-17.08 pmol/L and TSH 1.675 ulU/ml and my RAIU result 2hr.uptake is 6.4% and 24hr uptake is 21.1% and my THYROID SCAN BY I-131
      I am hoping I can ger a feedback from you Doctor.

  1. Hi
    I have been on 2 grains of Armour for awhile. I am still struggling with low energy in the afternoon and resistance to losing weight.
    I also occasionally feel an inner chill.
    My labs indicated a low T4 and T3 at the higher range. My doctor added a low dose of Synthroid to be taken mid day. It seemed to help
    at first but then felt jittery after a month so stopped.
    I have also had adrenal issues that I supplement with DHEA and pregnenolone.
    Running out of options…

    • Do research on adrenal cocktail. Thyroid and adrenals go hand in hand. A boost of minerals and salts naturally gives energy. Supplement with magnesium too.

  2. Yea. Sometimes I’m still getting cold easily, but since I’ve started the hypothyroid bundle things are much better. I believe that when I’m on a regular fitness workout that has a lot to do with it too. And Summertime!

    • Hi Deborah,

      Thanks for sharing! And yes, exercise can stimulate both thyroid production and heat production so it should help 🙂

  3. I have no thyroid and I’m on 125 mg of Levothyroxine. Even when dosing to 150 mg my hands and feet stay extremely cold, especially during winter time. So it always makes me susipicious to know what else can be done next to rising the dose (TSH drops even to 0.2), if symptoms are still due… Many other symptoms exsist next to cold intolereance, so I’m sure its related to thyroid.

  4. I am curious to know what you think about a thyroid test called “Thyroflex.” Is it a valid and reliable method for evaluating thyroid performance? Thank you.

  5. Thank you so much for all this information. I have been suffering from cold intolerance for years and understood that it was some sort of disorder because it wasn’t normal. Although I never thought it could be linked to hypothyroidism but it makes so much sense. I don’t have medical aid currently so I can’t get tests done but I’ll start looking at natural methods to alleviate this. Thank you so so much.

  6. I have Hashimoto’s and I run hot all the time! I have the hardest time cooling off, and I live in AZ where it’s hot most of the time. But, when it’s cold, I get really cold. I wish I could find a nice balance!

  7. I have subclinical hypothyroidism and take T3 medication. What complicates my cold intolerance is I also have Dysautonomia/POTS Syndrome that can cause the same symptom. I’ve seen some improvement with T3 and supplements for Dysautonomia, but honestly, the decision that helped me the most was moving away from the frigid Northeast. My health dramatically improved both in Southern California and North Carolina. My body prefers warm climates, and I have no problem with that! A milder climate + the right treatment is life changing for me.

  8. Can having had a procedure (EGD)with propofol as the anesthetic worsen thyroid function? I am hypothyroid due to subacute thyroiditis 4+ years ago. I’m having new problems (10 days post op) feeling cold and below normal measured temps, but not all day. Since menopause and the SAT, I have had terrible temp regulation issues, previously “running hot” with adequate TFTs, now seems to be going the other direction.

  9. Hi. I’ve had Hashimoto’s for probably most of my life without even knowing that’s what was causing my slow metabolism, so many intolerances and indigestion until my yearly physical exam bloodwork showed my TSH levels through the roof. I was immediately prescribed Synthroid, but decided to work with a Naturopathic doctor instead for an NDT solution. After roughly 3 years of trying different dosages and products, we finally hit the right one for me which was a compounded mix of T3/T4 since I have issues with pork and I didn’t take well to the NDT products. Now my levels are optimal thanks to the ND. Prior to hitting on the correct type and dosage, I was still very much sluggish and cold all the time. I no longer have those issues, but I’ve also made changes to my eating habits by staying away from the known food triggers. Dr Childs has been instrumental in my journey to understanding this autoimmune disorder. It takes time, but once you make changes to your eating habits, lifestyle choices and hit on the right thyroid mix, the coldness and slow metabolism goes away. It did for me anyway and I’m forever thankful.

  10. I’m taking T4 88mcg/T3 25 mcg and trying to get optimal while continuing to raise my T3 dose…My last RT3 was 22.9. I feel like I still am hypo even though my TSH doesn’t indicate that. Is the RT3 causing that? My current doctor never mentions it or seems concerned about my RT3… (I had that checked on my own.)

  11. Hi! I’m 35 and I have had hypothyroidism for 10 years, since the birth of my daughter. I have been on 75 mg synthroid. The last 5 years I have suffered from insomnia, weight gain, achy joints, low grade fever, and cold intolerance. Several doctors including 2 endocrinologists have tested my thyroid numerous times and every single time they tell me all of my numbers are in perfect range. They have never adjusted my dosage. I’m frustrated because I feel like no one will listen or help. I too sleep in socks and two blankets, wear a sweat shirt or pants in the house because I’m always cold. Please help

  12. My body temperature has been sub-normal for a while now, but my medical providers don’t even want to deal with it. When I bring it up, they act like it’s no big deal.

    Once cold weather hits in the Autumn, my feet get chilly, and they stay that way until late Spring.

    I’m tired, I’m sluggish, I’ve been told I have fibromyalgia. It takes all that I have to get my basic daily chores done.

    I started taking a raw adrenal supplement a couple of weeks ago, but don’t really notice any difference.

  13. I’m freezing in the winter, any temp under 80 I don’t like. My body temp normally registers 96.7. And I sweat really badly from my head in the summer. I wear headbands all summer. My thyroid tests always come back normal. I have been eating a ketogenic diet for almost six years. I have eaten a predominantly carnivore diet for almost two years.

  14. No matter how many times I fill in my name and email address to get your free download information, it never shows up in my inbox or junk mail folder. How can I get this information?

  15. What about those of us who run hot all the time? I am taking npthyroid and 5mcg T3 and my labs are perfect. But I still run hot…like the temp has to be below 64 for me to not sweat.

  16. Hi Dr. Childs,
    Thank you so much for all of the information you provide us. I really really wish I could see you. This article hit home because I suffer from cold intolerance alll the time. I can’t seem to find a thyroid doctor who looks beyond the standard lab tests. I just feel like you would be able to help me. I’ve been on 150mcg of levothyroxine for @25 years. One doctor added 10mg of liothyronine a day but I am still freezing, tired and putting on weight. I had Hashimoto’s and a thyroidectomy because it was so enlarged that I was choking all the time. It’s so frustrating to feel so lousy all the time. Thank you so much.

  17. Hello Dr.
    Based on recent lab test, My TSH is about 5.25 and T4 is 1.0 . I am now on 75 mg Synthroid, after used to have Levo 25 mg, then increased to 50 mg, for my hypothyroidism, per family doctor.

    Lost few pounds, feel more energy than before while taking Synthroid 75 mg. But, I feel little cold but not as you described it above. However; I feel more heat than cold. I sweat a lot for light activities or sitting in normal heated areas, plus I sweat sometimes at sleep. No T3 reading were taking by lab test.

  18. Sorry doctor,

    following my early post, I forgot to mention that my thyroid anti-body (TPO) is 190 from the same lab test report of TSH 5.25 & T4 is 1.0. Thanks

  19. Wow….. the sock test? I was sleeping in socks and wearing a flannel nightgown in summer— we thought I was just a bit crazy. All summer I wore sweatshirts….embarrassing…. But ever since my doctor increased my t3 medication to 10 mcg, I started to have normal reactions to the environment. My most recent labs show a 0.7 tsh , t3 and t4 are still in the low normal range, but the best news is that my reverse t3 is down to 11. No more socks!

  20. What about heat intolerance? I feel like I’m going to pass out and die in summer — sounds extreme but it is. I can’t enjoy the things that I used because I am unable to leave the house comfortably in the heat. Used to surf and enjoy summer, spend the whole day in the sunshine at the beach. Was given Zoladex in 2011 for endometriosis and it caused me so many autonomic issues. I am stuck with them still 8 years later. They then found papillary thyroid carcinoma at the beginning of this year which had developed from nodules I had been living with for years. All my bloods were ‘normal’ range but TSH swinging around the place most of the time. Quite low at times. My thyroid is out now due to the nodules that turned cancerous — I feel about the same. Bit better maybe? Some days. Just still sensitive to the heat though and still have the palpitations that I had prior to surgery, with exercise intolerance when I was very fit before any of this happened and no symptoms. Hard to lose weight now. It’s like I have mixed symptoms of hyper and hypo. Am I able to consult with you please? I’m an EMT with a two year old son and I’ve been off work for years. I just want my quality of life back and to be a good parent again who can play and enjoy life. Here in Australia, I am just on levothyroxine and getting told it’s normal to feel this way now. Please help me.

  21. Now I’m even more confused than I was before I read about Cold Intolerance. I’m 57 and have been treated for Low Thyroid for about 6-7 years ever since my periods stopped. I am sweating and or feeling warm, to the point of my make up melting. I turn the ceiling fans on in every room and have a desk fan at work. Prior to this change of life and being put on hypothyroid medications; levothyroxine (could not take whatsoever), Cytomel (could not take either), Synthroid (could not take), Nature Throid (was taking before recent recall) and currently taking Armour Thyroid (I wake up sweating – not my favorite). Maybe it’s because I live in AZ where the average temperature is 100? Just really baffled now why I’m not cold and the doctors I’ve seen prescribe medication that makes me hot?

    • I have been on levothyroxine for 45 years. Three months ago I switched to Armour 60 mg. Since then I sleep better and generally feel better; however, I now experience both cold and heat intolerance. I take the Armour in the morning when I first get up. By the afternoon I’m always freezing cold, even when it’s 90° outside. Then in the evenings I start to get hot flashes and get really sweaty. I’m 68 years old and did not experience these kind of hot flashes when I went through menopause!!! Perhaps I need a higher dose or Armour?

  22. I have cold intolerance and have always slept with socks on my feet. I take NDT, and have taken different thyroid meds because of recalls. It doesn’t seem to make a difference which NDT I take. I can’t take a higher dose because it makes my heart race and my TSH extremely low. I have had full thyroid panels done. all my numbers are in range. I am not sure what I can do.

  23. Hi. I have a full thyroid panel done each year. Everything comes back normal. TSH stays just above 2 & other labs WNL. I am on 25 mcg of Levo. I do experience cold intolerance (but don’t need to wear socks in the summer!). I live for warm sunny weather and can get chilled easily if the sun tucks behind the clouds in warm weather! I am miserable when the temperature starts to drop. Do you think upping my Levo dose to 50 mcg could help? Also, would using a heat type lamp over the colder months be helpful? Thanks!

  24. I am on Synthroid. I walk around with a cardigan all the time..even in the summer. I sleep with warm Canadian winter socks on all the time. We bought a pool heater because the water was never hot enough for me…now our pool is like a sauna..not very refreshing in the summer heat for others but perfectly comfortable for me. 🙁

  25. I have tested positive for Hashimotos. I wear socks for cold feet at night. My last labs were:
    tsh. 0.72, T3. 2.8, T4. 0.54. (Low)
    I take 15mcg liothyronine daily.
    I also take 4.5mg of low dose naltrexone. My thyroid
    peroxidase an has gone from 369.2 on 2-5-15 to 6.5 on 5-15-20. My anti-microsomal antibodies went from 1:40 to negative on same dates. Shouldn’t my liothyronine be raised? I couldn’t tolerate levothyroxine and was on armour for a while but was taken off that quite a while ago.

  26. I am 54 years old and have Hashimoto’s and Leaky Gut. I was taking Armour Thyroid for 5 years with no problems. My PCP or the pharmacy (not sure which) changed my meds to NP Thyroid in March 2020 without my knowledge. I was taking 90 Mg per day as prescribed. I started getting Cold intolerance, gaining weight and was very fatigued by the beginning of April. Then the Heartburn set in. It was awful. I got it even if I didn’t eat anything and would do physical activity. I called the doc, he gave me Prilosec. OF course because of Covid, I couldn’t make an appointment to see a doctor so things continued to get worse. I am also on Hormone Replacement Therapy of Estrogen and Testosterone. I got my pellets on May 13, 2020 and within 2 weeks I was destroyed. I got hot flashes, depression, fatigue, severe anxiety and panic attacks, hair falling out, nails breaking off. Then came the bad/good new on May 23, 2020. NP Thyroid had been recalled for super potency and my pills had been in the lots that were recalled. Now to recovery. I got my labs, my TSH was 17.7, my antibodies were at 614, T3, T4 were all way off. (I don’t have them in front of me so I can’t give you specific numbers) Cholesterol was HIgh, Sugar was High, Vitamin D was low, and finally the answer to my indigestion and heart burn question was answered. I was put back on Armour 60 Mg per day, given supplements for my blood sugar and cholesterol, Vitamin D. I completely changed my diet, no gluten, no dairy, no processed foods, no refined sugar. I ate Bone Broth, fish, and healthy foods.
    Things were slow but progressing. I have dropped the weight, and started feeling better. Then on August 13, 2020 I got my pellets again and they upped my estrogen. On August 23, 2020 I was a mess again. Depression, Anxiety, panic attacks, fatigue. I was again on the rollercoaster I drastically wanted to get off of. My question and I believe I may have read it on your blog. I read that Estrogen can hinder the conversion of T4 to T3 and go estrogen dominant. Can the HRT be causing a problem with my Thyroid? Should I get my thyroid issue in check before getting these hormones? This is the second time it has happened within 10 days of getting my pellets and I would rather not have a 3rd time. Thank you for your help.


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