The Brain That Controls Cortisol: HPA Axis, Brain Fog & Adrenal Insufficiency (Part 1)

Why can brain fog, memory difficulties, or mental fatigue persist when you are already taking cortisol replacement for adrenal insufficiency? Understanding the brain’s role in cortisol regulation helps explain why the answer involves more than the adrenal glands—and why symptoms deserve a broader medical evaluation.

In Part 1 of “The Brain on Cortisol: More Than a Stress Hormone,” this My Adrenal Life conversation explores Karen Harbison’s article, “The Brain That Controls Cortisol.” Finn and Mia unpack the hypothalamic-pituitary-adrenal (HPA) axis and the two-way communication between cortisol and the brain.

In this episode:

• How CRH, ACTH, and cortisol work together through negative feedback

• How primary, secondary, and tertiary adrenal insufficiency interrupt different parts of that signaling system

• Why essential glucocorticoid replacement does not necessarily restore natural cortisol production

• Mineralocorticoid and glucocorticoid receptors in the brain, and why concentration and timing matter

• Circadian rhythms and ultradian pulses, and the limits of conventional oral replacement

• What research suggests about cognitive symptoms—and why mixed study findings do not support one explanation or treatment for everyone

Cognitive difficulties do not automatically mean your cortisol replacement is inadequate. Sleep and other medical conditions can also contribute. Discuss persistent symptoms with your healthcare team; this episode does not recommend changing medication or doses.

Recovery after glucocorticoid-induced HPA suppression varies among individuals. Neither recovery nor improvement in cognition from a particular replacement approach is guaranteed.

Learn more about living with adrenal insufficiency:

https://MyAdrenalLife.com

Connect with others—request to join the My Adrenal Life Facebook group:

https://www.facebook.com/groups/myadrenallife

Based on the November 11, 2026 article by Karen Harbison:

https://www.facebook.com/groups/myadrenallife/posts/1596857992169982/

AI-generated hosts. Educational information and community support, not individualized medical advice. Discuss personal care with your qualified healthcare team.