How does coffee intake affect cortisol levels?

Coffee Acutely Increases Cortisol Levels, But Tolerance Develops With Regular Use

Coffee consumption causes an immediate rise in cortisol secretion in caffeine-naive individuals, but regular daily intake of 300-600 mg caffeine substantially reduces this cortisol response, though it does not eliminate it entirely. 1

Acute Effects in Non-Regular Users

• In individuals who abstain from caffeine for 5 days, a single 250 mg caffeine dose (approximately 2-3 cups of coffee) causes a robust increase in cortisol levels throughout the day 1
• This cortisol elevation occurs both at rest and is amplified when combined with mental stress or exercise 2, 3
• The effect is dose-dependent, with dietary doses of caffeine (3.3 mg/kg body weight, equivalent to 2-3 cups of coffee) significantly elevating both ACTH and cortisol in plasma 3

Tolerance Development With Regular Use

The cortisol response to caffeine is substantially blunted in regular coffee drinkers, though not completely eliminated. 1

• After 5 days of regular caffeine intake at 300 mg/day or 600 mg/day, the cortisol response to the first morning caffeine dose is abolished 1
• However, cortisol levels still become elevated between 1:00 PM and 7:00 PM after subsequent caffeine doses, indicating partial but incomplete tolerance 1
• Habitual caffeine users demonstrate heightened cortisol reactivity specifically to psychosocial lab-based stress compared to non-users, suggesting chronic adaptation of the HPA axis 4

Sex Differences in Response

• Women and men show similar baseline cortisol levels but respond differently to the combination of caffeine and stressors 2
• The cortisol response to mental stress is smaller in women than men, but caffeine acts similarly in both sexes to further increase cortisol during mental stress 2
• After exercise followed by a meal, women show a larger cortisol response than men, and this effect is amplified by caffeine 2

Clinical Context: Blood Pressure Considerations

While the ACC/AHA guidelines note that coffee causes acute increases in blood pressure, long-term coffee use is not associated with increased blood pressure or cardiovascular disease 5. The guideline recommends:

• Generally limiting caffeine intake to <300 mg/day in patients with hypertension 5
• Avoiding use in patients with uncontrolled hypertension 5

Practical Implications

For individuals concerned about cortisol levels, regular moderate coffee consumption (300-400 mg/day or 3-4 cups) results in less cortisol elevation than intermittent use due to tolerance development. 1

• The cortisol-stimulating effect is most pronounced in caffeine-naive individuals or those who consume coffee sporadically 1
• Repeated daily caffeine doses increase cortisol levels across the day regardless of sex or type of concurrent stressor 2
• This cortisol response may have behavioral activating effects that could be protective against depression in habitual users 4