Does Coffee Increase Cortisol Levels?
Yes, coffee acutely increases cortisol levels in both habitual and non-habitual users, though tolerance partially develops with regular consumption. The evidence consistently demonstrates that caffeine stimulates cortisol secretion, but this effect is modified by consumption patterns and timing.
Acute Effects on Cortisol
Coffee consumption causes robust cortisol elevation in caffeine-naive individuals:
- A single dose of caffeine (250 mg, equivalent to 2-3 cups of coffee) significantly increases cortisol secretion throughout the day in people who have abstained from caffeine 1
- The cortisol response occurs within 60 minutes of consumption and persists for several hours 2
- This effect is consistent across both men and women, though the magnitude may vary by sex and context 3
Tolerance Development with Habitual Use
Regular coffee consumption modifies but does not eliminate the cortisol response:
- After 5 days of regular caffeine intake (300-600 mg/day), the cortisol response to the first morning dose is abolished, but subsequent doses later in the day still elevate cortisol levels 1
- Habitual caffeine users show heightened cortisol reactivity when exposed to psychosocial stress in laboratory settings, suggesting sensitization rather than complete tolerance 4
- The cortisol-elevating effect persists even in regular users, particularly with repeated doses throughout the day 3
Clinical Context and Mechanisms
The cortisol increase from coffee has specific clinical implications:
- Caffeine prevents the normal decline in serum cortisol concentrations that occurs throughout the day in healthy adults 2
- The effect is amplified when coffee is consumed during periods of mental stress or exercise, with additive increases in cortisol beyond either stressor alone 3, 5
- Individuals at high risk for hypertension show more persistent cortisol elevations in response to caffeine plus stress 5
Important Caveats
The cortisol-raising effect of coffee should not be confused with its health benefits, which derive primarily from chlorogenic acids and other phytonutrients rather than caffeine itself 6. The American Heart Association notes that both caffeinated and decaffeinated coffee demonstrate health benefits in epidemiological studies, indicating caffeine is not the primary driver of coffee's protective cardiovascular and metabolic effects 6.
For most healthy adults consuming moderate amounts (3-5 cups daily), the ACC/AHA guidelines note that long-term coffee use is not associated with increased blood pressure or cardiovascular disease despite acute cortisol increases 7. The transient cortisol elevation does not translate to adverse long-term outcomes in the general population.