• Cortisol is crucial for maintaining energy balance, especially during fasting or stress:

  • Increases gluconeogenesis in the liver → raises blood glucose
  • Breaks down proteins (catabolism) for amino acids
  • Mobilizes fats for energy (lipolysis)
  • Reduces glucose uptake in peripheral tissues (insulin antagonism)

Goal: Maintain blood glucose and energy during stress or fasting

Cortisol regulates immune function by:

• Inhibiting cytokine production (e.g., IL-1, IL-6, TNF-α)
• Suppressing T-cell activation and inflammation
• Reducing histamine release and stabilizing mast cells

Used therapeutically as steroids (e.g., prednisone) in autoimmune or inflammatory conditions

• As part of the HPA axis, cortisol:

  • Helps the body adapt to physical and psychological stress
  • Supports cardiovascular tone, blood pressure, and alertness
  • Works with adrenaline to handle acute stress

Known as the “stress hormone”

Cortisol helps maintain vascular tone and enhances the effect of catecholamines (like norepinephrine).

• Mild mineralocorticoid activity: promotes sodium retention and potassium excretion (less than aldosterone)

Supports normal blood pressure and fluid balance

Cortisol receptors are found in the hippocampus, amygdala, and prefrontal cortex:

• Regulates mood, motivation, and memory
• Both low and high levels are linked to:
  • Depression
  • Anxiety
  • Memory problems
  • Sleep disturbances

• Inhibits bone formation (reduces osteoblast activity)
• Promotes bone resorption → prolonged excess may cause osteoporosis
• Thins the skin with prolonged high levels

• Follows a daily cycle:
  • Highest in the early morning (around 6–8 AM)
  • Lowest at night (midnight)
• Regulates wakefulness and energy cycles