The Effect of Stress on Cortisol and Thyroid Hormones

by | Aug 11, 2022 | nutrition, self care

Chronic stress affects most of us at one time or another. Humans are designed to withstand intermittent episodes of stress quite well physiologically. However, in these modern times, it has become common to have more prolonged bouts of stress; these sustained periods can take a toll on our bodies.

One particular area of concern regarding the impact of stress is the thyroid.

What does the thyroid gland do in the body?

The thyroid is an endocrine gland located in the neck. It produces two hormones: thyroxine (T₄) and triiodothyronine (T₃). These hormones are responsible for regulating the body’s metabolism.

The thyroid also produces a hormone called thyroid-stimulating hormone (TSH), which helps regulate the production of T₃ and T₄. (1)

When thyroid function is disrupted, many symptoms can arise. Hyperthyroidism (over-production of thyroid hormones) and hypothyroidism (under-production of thyroid hormones) are two common conditions that result from a dysfunctional thyroid.

Symptoms of hyperthyroidism

Weight loss


Heart palpitations

Difficulty sleeping

Increased appetite

Symptoms of hypothyroidism


Weight gain

Dry skin



Feeling cold or body temperature dysregulation

Woman with low thyroid laying on a log asleep

What role do cortisol levels play?

When we encounter stress, the adrenal glands release a hormone called cortisol. Cortisol sends throughout our bodies that it is time to react. You may know this as fight or flight.

Many physiological functions, such as digestion, are put on hold during fight or flight. At the same time, accelerated heart rate, energy transport to muscles, and increased lung capacity are prioritized to help us fight or get away (2). Interesting detail about the stress response can be found in this Harvard Health article. (3)

Hypothyroidism and Cortisol

Influenced by the secretion of cortisol, thyroid function is typically downregulated in times of stress. So when our experience of stress is constant and unrelenting, it can have a negative impact on the thyroid gland and its ability to produce thyroid hormone. Over time, hypothyroidism can develop, a decrease in thyroid function leading to the symptoms stated above. (4)

The implications of cortisol’s effect on thyroid hormone are far-reaching. Cortisol has been shown to play a role in the development of thyroid-based autoimmune conditions, Graves’ disease, and Hashimoto’s thyroiditis. Additionally, longer-term elevated cortisol can cause

  • increased blood sugar
  • high blood pressure 
  • poor digestion 
  • poor immune function 
  • decreased metabolism
  • mood disruption
  • chronic fatigue
  • insomnia
  • migraines


What blood work should you get for a thyroid issue?

There are a few different tests that assess thyroid function. The most common test is the Thyroid Stimulating Hormone (TSH) test. This test measures the level of TSH in the blood and can give clues as to whether the thyroid is under-or over-active.

Other tests that may be done include:

Free T₄ (FT₄)

This measures the amount of free thyroxine in the blood.

Total T₃ (TT₃)

This measures the total amount of triiodothyronine, which is the active form of thyroid hormone, in the blood.

Reverse T₃ (rT₃)

Reverse T3 is the inactive form of thyroid hormone.

Thyroid antibodies (TPO and TGAb)

Antibody tests measure the levels of antibodies in the blood that are attacking the thyroid gland. Antibodies present in the blood can indicate autoimmune conditions such as Hashimoto’s thyroiditis or Graves’ disease.


Which test assesses cortisol performance?

Measuring your cortisol levels using a DUTCH test can show you your pattern of cortisol performance throughout the day. Certain patterns paint a picture of how stress affects you physically, providing information to your practitioner about which treatment may be best for you.

Many supplements can be helpful to get cortisol levels back on track. A DUTCH test can help your nutritionist know which supplements to use to target specific symptoms you are experiencing.

If you’d like to know more about the DUTCH test and how it might benefit you, click the button below for a free consultation!!!





  1. “Thyroid Hormone: What It Is & Function.” Cleveland Clinic, Accessed 29 June 2022.
  2. Tsigos, Constantine, et al. “Stress: Endocrine Physiology and Pathophysiology.” Endotext, edited by Kenneth R. Feingold et al.,, Inc., 2000. PubMed,
  3. “Understanding the Stress Response.” Harvard Health, 1 Mar. 2011,

The Effect of Stress on Cortisol and Thyroid Hormones

by | Aug 11, 2022 | nutrition, self care