The Thyroid / Adrenal Connection – Is it a thyroid or cortisol problem?

Often, at Naturmend, we see people who have symptoms of low thyroid function. Things like weight gain, fatigue, brain fog, hair loss etc. Yet, when they’ve been tested their thyroid hormones continually come back in the normal range.

OR we see people who have been diagnosed with hypothyroidism (low thyroid function). And after initiation of thyroid medication and the normalization of all their thyroid tests, they continue to feel the same symptoms of fatigue, hair loss, weight gain, brain fog etc.

What is happening in these two scenarios?

We need to look closely at the hormones involved and secreted by the adrenals and the thyroid. These two essential organ systems are responsible for much of the important hormonal happenings in our bodies.

thyroid-1The thyroid is found in the neck and is responsible for producing thyroid hormones which help in the regulation of metabolism. The adrenals are small glands situated on top of the kidneys, that function in producing several hormones. These include: stress hormones (epinephrine, norepinephrine, and cortisol), some sex hormones, and mineralocorticoids which regulate fluid balance and blood pressure.

To help explain what’s happening above we are going to focus in on the interaction between cortisol and the thyroid hormones.

What we know is that excess cortisol suppresses TSH secretion (1). TSH is a hormone produced by the brain that tells the thyroid to make more thyroid hormone. In essence then, excess cortisol inhibits the thyroid from making more thyroid hormones.

Conversely when cortisol is low, TSH levels are shown to increase (2,3) which is a sign of a poorly functioning thyroid. Additionally, low levels of cortisol also decrease T3’s (active thyroid hormone) affinity to its receptors in the tissues where it is active (4). So we see that low cortisol is linked with lower thyroid function.

From this we see that both low and high cortisol can create symptoms of low thyroid function.

Let’s focus a bit more on the low cortisol situation as that is what we see most commonly. When researchers look at patients with adrenal insufficiency (inability to make much or any cortisol from the adrenals) they present with high TSH and hypothyroid symptoms (4,5) and over time a decrease in T4. These people will not respond favourably to thyroid medication unless the cortisol levels are treated as well (4). This makes sense when we know that cortisol is needed to allow thyroid hormone to work properly in the tissues. This highlights the importance of adequate cortisol levels to have a well functioning thyroid system. Not too much and not too little.

For these reasons, for any patient suffering from thyroid symptoms or already diagnosed with a thyroid disorder, I like to investigate what is happening with their cortisol levels throughout the day. After testing many patient’s cortisol levels, I find it very common in my practice to see low cortisol levels. Now we know that with low cortisol we can see elevations in TSH (sometimes mild, but still there) and in some cases low thyroid symptoms may show up.

Often if we can restore adequate cortisol levels, the TSH will normalize. Sometimes patients can lower their dose of thyroid medication if they are on it (under the supervision of their prescribing doctor always) or they just feel a lot better and we see a reduction or elimination of the low thyroid symptoms they’ve been suffering from.

hormones1Take home points:

  • Your low thyroid symptoms might not be purely a thyroid problem. If cortisol levels are too high or too low, this will compromise thyroid function.
  • If you have cortisol imbalance, it is hard to correct thyroid symptoms with purely thyroid treatment. It’s important to also support cortisol levels.
  • If you are one of those suffering from low thyroid symptoms, despite normal thyroid numbers – either on medications or not, then consider getting your cortisol levels evaluated by an ND or functional medicine practitioner.


Dr. Meaghan McCollum, ND

Meaghan-130x150I am a strong advocate of integrated healthcare. To me this means bringing together all forms of healthcare from your healthcare team and communicating to help you reach your health goals. I work along side all types of practitioners and treatments.




1. Samuels, MH. Effects of variations in physiological cortisol levels on thyrotropin secretion in subjects with adrenal insufficiency: a clinical research center study. J Clin Endocrinol Metab. 2000;85(4):1388-1393.

2. Hangaard J, et al. Pulsatile thyrotropin secretion in patients with Addison’s disease during variable glucocorticoid therapy. J Clin Endocrinol Metab. 1996;81:2502–2507.

3. Hangaard J, et al. The effects of endogenous opioids and cortisol on thyrotropin and prolactin secretion in patients with Addison’s disease. J Clin Endocrinol Metab. 1999;84:1595–1601.

4. De Nayer, P et al. Altered interaction between triiodothyronine and its nuclear receptors in absence of cortisol: a proposed mechanism for increased thyrotropin secretion in corticosteroid deficiency states. 1987;17(2):106-10.

5. Abdullatif, HD, Ashraf, AP. Reversible subclinical hypothyroidism in the presence of adrenal insufficiency. Endocr Pract. 2006;12(5):572-575.

4 Responses to “The Thyroid / Adrenal Connection – Is it a thyroid or cortisol problem?”

  1. Ann Hansen

    I have to High cortisol because I have problems with my metabolisme
    I have hypothyroid problems and I can not tolerate any thyroid medication
    My rt3 gets to High
    I am very sick
    What can I do ?
    I live in Denmark and my doctor don’t know any thing about this

  2. I am very frustrated. In identifying ulcers , gastritis, esophagitis, IBS and ruling out other issues an adrenal gland tumor was found. Not so abnormal I am told. I asked for an evaluation to be sure. Blood tests found I have less than 0 cortisol. So I asked for a full thyroid panel including free t3 and t4. I am told the thyroid panel is normal so all is well. I don’t get it??? I am exhausted, weepy, constipated, and have gained 20 lb in 6 months. Is low cortisol a problem and cannot be fixed or is it no concern?? And just because the benign tumor is not effecting aldosterone could it be the culprit of less than O cortisol???

    • Naturmend

      Hi Trudy, thanks for your comment! Unfortunately we aren’t able to provide such specific health advice over this platform. I welcome you to book in with one of our naturopathic doctors here to get connected with a support team who can help you out.

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