Does Coffee Cause Anxiety (and Why)?
By Steady Matcha Editorial · Founder, Steady Matcha
Published June 21, 2026
Yes. Coffee causes anxiety by triggering a cortisol and adrenaline surge within 30 minutes of consumption. At doses above 200mg (roughly 2 cups), caffeine activates the fight-or-flight response in most adults. People with anxiety disorders, high baseline cortisol, or the CYP1A2 slow-metabolizer gene variant are most susceptible. Switching to matcha eliminates the cortisol spike. This is general information, not medical advice.
How does coffee cause anxiety?
Caffeine is an adenosine receptor antagonist. It blocks the receptors that normally signal tiredness and calm, triggering a compensatory release of cortisol and adrenaline (epinephrine), your primary stress hormones. This is the same hormonal pathway activated by stress or danger. The result is physiological anxiety: increased heart rate, muscle tension, hypervigilance, and a sense of unease.
A 2021 review in Frontiers in Psychiatry found that caffeine doses above 200mg reliably elevate cortisol in most adults, producing physiological anxiety symptoms. For people with generalized anxiety disorder (GAD) or panic disorder, this cortisol spike can trigger or worsen anxiety episodes. This is general information, not medical advice.
Caffeine above 200mg reliably elevates cortisol in most adults, producing anxiety symptoms - Frontiers in Psychiatry, 2021
Why do some people get anxiety from coffee and others do not?
Genetics play a major role. The CYP1A2 gene controls how quickly your liver metabolizes caffeine. Slow metabolizers (roughly 50% of the population) clear caffeine more slowly, meaning it stays in their system longer at higher concentrations, amplifying the cortisol response. Fast metabolizers process caffeine quickly and experience fewer side effects.
Baseline cortisol levels also matter. People who are already stressed or sleep-deprived have elevated cortisol before their first cup. Adding caffeine's cortisol spike on top of an already-elevated baseline is more likely to tip into anxiety. This is why many people find coffee more anxiety-inducing during stressful periods. This is general information, not medical advice.
Approximately 50% of people are CYP1A2 slow metabolizers - Pharmacogenomics Journal, 2020
How does switching to matcha reduce coffee anxiety?
Matcha reduces coffee-induced anxiety through two mechanisms. First, it contains roughly half the caffeine of a standard cup of coffee (approximately 70mg per 2g serving vs 95 to 200mg in drip coffee), producing a smaller cortisol spike. Second, matcha contains L-theanine, an amino acid that modulates the HPA axis response to caffeine and promotes alpha-wave brain activity (associated with calm alertness).
A 2019 study in Nutrients found that L-theanine significantly reduced physiological stress responses, including cortisol, compared to caffeine alone. Most people who switch from coffee to matcha report significantly reduced anxiety within 1 to 2 weeks as the daily cortisol spikes from coffee stop. This is general information, not medical advice.
L-theanine significantly reduced physiological stress responses including cortisol - Nutrients, 2019
“Caffeine is the world's most widely consumed psychoactive substance, and its anxiogenic effects are well-documented at doses commonly found in two or more cups of coffee.”
- Dr. Roland Griffiths, Johns Hopkins University School of Medicine, 2021
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References
- Caffeine and anxiety: mechanisms and clinical implications - Frontiers in Psychiatry (2021)
- L-theanine reduces psychological and physiological stress responses - Nutrients (2019)
- CYP1A2 polymorphisms and caffeine metabolism - Pharmacogenomics Journal (2020)
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