The Relationship between Cortisol & Thyroid Hormones

Did you know that many people have both thyroid and adrenal/cortisol problems AND the symptoms actually include a lot of overlap! 

Thyroid disease is a huge part of my clinical practice.

  • Around 15% or more suffer with low thyroid (hypothyroid) and Hashimoto’s thyroiditis (autoimmune).
  • Patients with PCOS have 3 times the risk of hashimoto’s!

The thyroid runs our metabolism – when it is low (known as hypothyroid) the metabolism slows down.

  • This can cause mood changes, weight gain, low energy, hair loss, poor memory and more
  • Thyroid hormones are involved in the metabolism/clearance of cortisol from the body. When thyroid hormones are too low, cortisol is cleared more slowly and levels can rise.
  • 🧠The brain -adrenal axis is also less responsive in hypothyroidism.
  • Unfortunately, high cortisol can also affect the thyroid!
  • High cortisol lowers TSH, and thyroid hormones causing symptoms that are easy to miss in labs.
  • high cortisol also blocks the formation of active T3 thyroid hormone from inactive T4 = hypothyroid symptoms.
  • Interactions between thyroid hormones and cortisol were found with TSH in the “normal range” >2.5<4.5. This would not be flagged on labs but has also been linked to insulin resistance in PCOS and Hashimoto’s.

Patients in my practice with thyroid disease report feeling best when their TSH is under 2. Of course, it’s never simple, for the many other causes for high and low levels of cortisol see some of my other posts!

PMID: 23111240, 33236107, 16148345, 1768405

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