5 ways that stress causes hypothyroid symptoms

August 2, 2010 in Stress, Thyroid Disorders | 19 comments

stressguyWe’ve already talked about how blood sugar imbalances and poor gut health can lead to hypothyroidism and Hashimoto’s. The harmful effects of adrenal stress complete the triad.

The adrenals are two walnut-shaped glands that sit atop the kidneys. They secrete hormones – such as cortisol, epinephrine and norepinephrine – that regulate the stress response. But these hormones play other crucial roles, many of which are directly related to thyroid health. In fact, as we’ll see in this article, proper thyroid function depends on healthy adrenal glands.

Most people are aware of the obvious forms of stress that affect the adrenal glands: impossibly full schedules, driving in traffic, financial problems, arguments with a spouse, losing a job and the many other emotional and psychological challenges of modern life.

But other factors not commonly considered when people think of “stress” place just as much of a burden on the adrenal glands. These include blood sugar swings, gut dysfunction, food intolerances (especially gluten), chronic infections, environmental toxins, autoimmune problems and inflammation. All of these conditions sound the alarm bells and cause the adrenals to pump out more stress hormones. In this context, stress is broadly defined as anything that disturbs the body’s natural balance (homeostasis).

Adrenal stress is probably the most common problem we encounter in functional medicine, because nearly everyone is dealing with at least one of the factors listed above. Symptoms of adrenal stress are diverse and nonspecific, because the adrenals affect every system in the body. But some of the more common symptoms are:

  • Fatigue
  • Headaches
  • Decreased immunity
  • Difficulty falling asleep, staying asleep and waking up
  • Mood swings
  • Sugar and caffeine cravings
  • Irritability or lightheadedness between meals
  • Eating to relieve fatigue
  • Dizziness when moving from sitting or lying to standing
  • Gastric ulcers

Weak adrenals can cause hypothyroid symptoms without any problem in the thyroid gland itself. In such cases, treating the thyroid is both unnecessary and ineffective, and addressing the adrenals themselves is the key to improving thyroid function.

The most significant indirect effect the adrenals have on thyroid function is via their influence on blood sugar. High or low cortisol – caused by any of the chronic stressors listed above – can cause hypoglycemica, hyperglycemia or both. And as we saw in a previous article, blood sugar imbalances cause hypothyroid symptoms in a variety of ways.

But adrenal stress also has more direct impacts on thyroid function. The following five mechanisms are the most important.

1) Adrenal stress disrupts the HPA axis

By now many people have heard of the hypothalamic-pituitary-adrenal (HPA) axis. It’s a complex network of interactions between the hypothalamus, the pituitary and the adrenal glands that regulates things such as temperature, digestion, immune system, mood, sexuality and energy usage – in addition to controlling the body’s reaction to stress and trauma.

Countless studies show that chronic adrenal stress depresses hypothalamic and pituitary function. And since these two organs direct thyroid hormone production, anything that disrupts the HPA axis will also suppress thyroid function.

Studies have shown that the inflammatory cytokines IL-1 beta, IL-6 and TNF-alpha, which are released during the stress response, down-regulate the HPA axis and reduce levels of thyroid stimulating hormone (TSH). Another study showed that one single injection of tumor necrosis factor alpha (TNF-alpha), an inflammatory peptide, reduced serum TSH, T3, free T4, free T3 and hypothalamic TRH for 5 days. TNF-alpha was also found to decrease the conversion of T4 to T3, reduce thyroid hormone uptake, and decrease the sensitivity of the thyroid to TSH.

2) Adrenal stress reduces conversion of T4 to T3

We discussed under-conversion of T4 to T3 in a prior article. Remember that although 93% of the hormone produced by the thyroid gland is T4, it is inactive in that form and must be converted into T3 before it can be used by the cells. The inflammatory cytokines I listed above not only disrupt the HPA axis, they also interfere with the conversion of T4 to T3.

The enzyme 5′-deiodinase catalyzes the conversion of T4 into T3 in peripheral tissues such as the liver and the gut. Both Th1 and Th2 inflammatory cytokines – IL-6, TNF-alpha, IFN-gamma and IL-1 beta – have been shown to suppress the conversion of T4 to T3. In patients without thyroid illness, as levels of IL-6 (a marker for inflammation) rise, levels of serum T3 fall. And injections of inflammatory cytokines into healthy human subjects resulted in a rapid reduction of serum T3 and TSH levels, and an increase in the inactive reverse T3 (rT3) form, while T4 and free T4 levels were only minimally changed.

3) Adrenal stress promotes autoimmunity by weakening immune barriers

The GI tract, lungs and the blood-brain barrier are the primary immune barriers in the body. They prevent foreign substances from entering the bloodstream and the brain. Adrenal stress weakens these barriers, weakens the immune system in general, and promotes poor immune system regulation.

As we discussed in my previous article on the gut-thyroid connection, when these immune barriers are breached large proteins and other antigens are able to pass into the bloodstream or brain where they don’t belong. If this happens repeatedly, the immune system gets thrown out of whack and we become more prone to autoimmune diseases – such as Hashimoto’s.

4) Adrenal stress causes thyroid hormone resistance

In order for thyroid hormone circulating in blood to have a physiological effect, it must first activate receptors on cells. Inflammatory cytokines have been shown to suppress thyroid receptor site sensitivity.

If you’re familiar with insulin resistance, where the cells gradually lose their sensitivity to insulin, this is a similar pattern. It’s as if the thyroid hormone is knocking on the cell’s door, but the cells don’t answer.

While there’s no practical way to measure receptor site sensitivity in a clinical setting, the research above suggests it is decreased in autoimmune and other inflammatory conditions. A perfect example of this in practice is the Hashimoto’s patient who is taking replacement hormones but still suffers from hypothyroid symptoms – often in spite of repeated changes in the dose and type of medication. In these patients, inflammation is depressing thyroid receptor site sensitivity and producing hypothyroid symptoms, even though lab markers like TSH, T4 and T3 may be normal.

5) Adrenal stress causes hormonal imbalances

Cortisol is one of the hormones released by the adrenals during the stress response. Prolonged cortisol elevations, caused by chronic stress, decrease the liver’s ability to clear excess estrogens from the blood. Excess estrogen increases levels of thyroid binding globulin (TBG), the proteins that thyroid hormone is attached to as it’s transported through the body.

When thyroid hormone is bound to TBG, it is inactive. It must be cleaved from TBG to become “free-fraction” before it can activate cellular receptors. (These free-fraction thyroid hormones are represented on lab tests as “free T4 [FT4]” and “free T3 [FT3]“.)

When TBG levels are high, the percentage of free thyroid hormones drops. This shows up on labs as low T3 uptake and low free T4/T3.

Aside from adrenal stress, the most common causes of elevated TBG secondary to excess estrogen are birth control pills and estrogen replacement (i.e. Premarin).

Balancing the adrenals

Here’s the tricky thing about adrenal stress: it’s almost always caused – at least in part – by something else. These causes include anemia, blood sugar swings, gut inflammation, food intolerances (especially gluten), essential fatty acid deficiencies, environmental toxins, and of course, chronic emotional and psychological stress.

When they exist, these conditions must be addressed or any attempt to support the adrenals directly will either fail or be only partially successful. With that in mind, here are some general guidelines for adrenal health:

  • Avoid or at least greatly minimize stimulants
  • Stabilize blood ´┐╝sugar (via a moderate or low-carb diet)
  • Practice stress management and relaxation techniques
  • Have fun, laugh and make pleasure a regular part of your life
  • Avoid dietary causes of inflammation (refined flours, high-fructose corn syrup and industrial seed oils in particular)
  • Ensure adequate intake of DHA & EPA

Specific nutrients such as phosphatidyl serine and adaptogenic botanicals like Panax ginseng, Siberian ginseng, Ashwagandha and Holy basil leaf extract are also helpful in modulating the stress response and supporting the adrenals. However, these are potent medicines and should be taken under the supervision of a trained practitioner.


Jess August 2, 2010 at 10:03 am

Thank you for tackling this complex and important issue! I wonder if you have any thoughts regarding cortisol and exercise. I know that exercise is important for reducing stress, but that intense or chronic exercise can increase your cortisol levels. However, the specifics of how much, what type, and recovery are a little overwhelming to me!

Chris Kresser August 2, 2010 at 10:08 am

Yes, intense steady-state exercise can elevate cortisol levels. I think a mixture of low-intensity activity like walking, gardening, bicycling, etc. plus high-intensity interval strength training is the best approach.

Charlotta (Sweden) August 2, 2010 at 1:29 pm

Is there a way to test for active contra inactive T3 or can one say anything obaout the common ration between the two? If I understand it right a regular blod test for FT3 really doesn’t say that much since you won’t know if it’s active or inactive T3?

Chris Kresser August 2, 2010 at 1:43 pm

Free T3 is free T3.  The inactive forms of T3 are reverse T3 (RT3), T3 sulfate (T3S) and T3AC. FT3 is the right test for measuring active T3 in the body.

Phoenix August 2, 2010 at 2:43 pm

So if Estrogen causes adrenal fatigue, is it possible that cyclic progesterone therapy could be helpful.
I am planning on doing it, to restart my cycle, and also rebuild some bone.
What are your thoughts on this?

Susan August 2, 2010 at 2:47 pm

The series keeps getting better, Chris. I’m the herbalist still skeptical of the problems with iodine, but everything else you say is right on! Especially good how you made the connection between adrenal stress and thyroid, since many herbalists (and other medicos) will say they are not connected.
The only missing element here is that you didn’t address nutrient deficiencies as broadly as I would. Not only are most ‘mericans deficient (esp in minerals) because of our depleted food supply, but stress gobbles up additional nutrients (esp B vits). I would never turn to botanicals until diet is fixed, stress is reduced, and nutrients are supplemented. I would supplement first at a high level for a few weeks (as insulin levels stabilize with reduced-carb diet), then reducing supplementation to a maintanance level.
Keep the great posts coming! -Susan in Florida

Chris Kresser August 2, 2010 at 2:52 pm


I wouldn’t say that estrogen causes adrenal fatigue.  Excess estrogen can cause hypothyroid symptoms by decreasing levels of active T3.

I don’t recommend direct hormone supplementation in cycling women.  Hormones are unbelievably potent substances, and taking them in cream form especially can cause serious imbalances because the body’s natural regulatory mechanisms are bypassed.  The best way to balance the hormones is to focus on adrenals, blood sugar, GI health and essential fatty acids.


Tyler August 2, 2010 at 3:53 pm

Chris, leaning on the side that I might be gluten intolerant, how would I truly go about finding out any food intolerances? Is there a definite way of testing besides eliminating the suspected cause entirely from the diet for a while and seeing the results?

Chris Kresser August 2, 2010 at 4:13 pm

Enterolab.com has the most accurate testing for gluten intolerance. However, as I mentioned in the article on gluten, the gold standard for identifying gluten intolerance is still the elimination/re-introduction test. This is what the top food allergists use because even the best tests are not infallible.

Charlotta (Sweden) August 3, 2010 at 3:02 am

Are you going to address the ovarian adrenal thyroid connection, if you consider there to be such a connection? And if so, do you believe that adrenal fatigue and/or thyroid problems can cause ovarian cysts and an early menopause?

java September 18, 2010 at 3:31 am

i have estrogen dominance and all associated symptoms.All my thyroid tests are within normal levels,but I show positive results for thyroid antibodies.What gives, any ideas ?

Chris Kresser September 18, 2010 at 7:43 am

Read this, especially #3.

Angela October 25, 2010 at 10:44 am

Once a person has been on T3 & T4 replacement for years if they stop taking it will it cause problems? Does the thyroid become dependent on it to function after taking it for years and is there a recommended way on how to come off it? I’m concerned about the meds doctors have put me on over the years not to mention I’d like to quit spending the money on it. My T3 medication is very expensive.
I’m also curious about your thoughts on MVP? A doctor put me on a beta blocker he said would control it even though others I know with MVP are not medicated. I became concerned when I read how that particular medication Cardizem is known to cause weight gain and I’ve had considered weight gain since I started taking it. I’ve since started working out 2 hours a day & eating healthy and now would like to just throw away all my medications. I’m just not sure if I am jeopardizing my health in any way by doing it or if I should stop cold turkey or gradually come off them?

Chris Kresser October 25, 2010 at 10:50 am

Angela: I can’t advise you on medication use.  I will say that those with Hashimoto’s and ongoing hypothyroidism often need to be on thyroid hormone replacement.  Thyroid hormone is so essential to proper function of the body that it’s not a good idea to have consistently low levels over a long period of time.  Eating healthy is helpful, but if you have an autoimmune condition attacking your thyroid gland, diet will not be sufficient to restore function.

Jeanne November 19, 2010 at 1:41 pm

I have experienced that controlling adrenal stress and estrogen is critical to managing Hashimotos in my daughter. Adaptogenic botanicals like Panax ginseng, Siberian ginseng, Ashwagandha have helped her adrenals tremendously, but also seem to increase her estrogen levels (read they are mildly estrogenic) and that has caused problems. What is your opinion on their ability to do this?

Chris Kresser November 19, 2010 at 5:38 pm

When you say “seem to increase her estrogen levels”, are you going by lab results or symptoms?

Perry January 21, 2011 at 1:26 pm

Hello Chris,

You wrote:

“Studies have shown that the inflammatory cytokines IL-1 beta, IL-6 and TNF-alpha, which are released during the stress response, down-regulate the HPA axis and reduce levels of thyroid stimulating hormone (TSH). Another study showed that one single injection of tumor necrosis factor alpha (TNF-alpha), an inflammatory peptide, reduced serum TSH, T3, free T4, free T3 and hypothalamic TRH for 5 days.”

Does this mean that when one stops taking an anti-inflammatory such as Ibuprofen, it is possible a down regulation in thyroid activity could occur due to up tick in the inflammation factors mentioned in the study?

Thank you

Chris Kresser January 21, 2011 at 1:42 pm

I suppose it’s possible. But it’s possible that NSAIDs could suppress thyroid function via their disruption of eicosanoid signaling.

Gluten Intolerance April 7, 2011 at 4:49 am

Wow! I learned a lot from this article. Also thanks to the mechanisms you shared. Does proper exercise would also prevent from adrenal stress and can help prevent causing hypothyroid?

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