Cortisol is more commonly known as the stress hormone. It is released by the adrenal glands upon signals from the HPA, the hypothalamic pituitary adrenal, and it is the chemical controller of far more than you thought: digestion and hunger, sleeping and waking, blood pressure and physical activity, as well as stress levels. It makes an appearance when you start to feel your cheeks flushing with anger or your hands shaking when you are flustered by an approaching deadline – it is the hormone that triggers the primal instinct fight or flight. It is also responsible for blood pressure regulation, insulin release for blood sugar level maintenance, functions of the immune system, and maintaining appropriate levels of glucose, as well as your inflammation response system.

However, today’s culture has us accustomed to long stretches of stressful periods, triggering our fight or flight instinct to constantly be in full gear. During these extended spells of stress, cortisol release becomes persistent and can lead to a range of health concerns; weight gain, disturbed sleep cycles, and stress binge eating are all results of this excess flow of cortisol in your system.

These fluctuating levels of cortisol can cause decreased metabolism, high blood pressure, depression, chronic fatigue, insomnia, migraines, acid reflux, tunnel vision, low immunity, arthritis, hunger cravings, and hostility.

How is cortisol related to thyroid health?

With conditions that involve thyroid hormone disturbances, such as hypothyroidism, healthy processes like weight loss become irregular. High levels of cortisol exacerbate this and slow down your thyroid even more. Cortisol also lowers thyroid hormones by decreasing TSH, which is responsible for triggering thyroid hormone production, reducing the level of thyroid hormone in circulation. Moreover, cortisol inhibits the conversion of the thyroid’s most prevalent hormone, thyroxine (T4), into the absorbable, bioactive thyroid hormones, triiodothyronine (T3) that speed up our metabolic rates. This instead increases the conversion of T4 in a way that reverses the already activated triiodothyronine.

Cortisol also indirectly affects thyroid health by influencing blood sugar. Too high or too low levels of cortisol can lead to hypoglycemia, hyperglycemia, or even the both. This imbalance in blood sugar has its own adverse effects on thyroid health by causing symptoms of hypothyroidism in different ways.

Adrenal stress will also have a direct adverse effect on thyroid function. In order for the circulation of thyroid hormones to mean anything, it is necessary for the thyroid receptors in the body’s cells to be activated. Otherwise, there will be no absorption of thyroid hormones no matter what their level of production is. Hypothyroidism has been linked to inflammatory cytokines.

This follows the same mechanism as insulin resistance. In insulin resistance, regardless of the level of insulin actually present in the blood, cells slowly lose their responsiveness to it. An example of this can be found in patients who suffer from Hashimoto’s. They may take supplementary or replacement hormonal treatments but continue to suffer from low levels of thyroid hormones, regardless of how much they try to tweak their dosage or type of medication. In patients such as these, the thyroid receptors are depressed, reducing site sensitivity due to inflammation and causing hypothyroidism, even if levels of TSH, T4, and T3 are optimal. Therefore, it is important to take into consideration cortisol levels when looking after the health of your thyroid and treating symptoms of hypothyroidism and hyperthyroidism.

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To your health & happiness!