Coffee Dose Found: Two to Three Cups Daily Linked to Lower Stress and Depression

A 2026 UK Biobank study of 461,586 adults over 13.4 years finds that two to three cups of coffee daily are linked to a lower risk of mood and stress disorders, with the benefit seen across caffeinated and decaf varieties and different coffee types. The protective effect follows a J-shaped curve: benefits peak at two to three cups and may diminish with higher intake. Possible mechanisms include caffeine blocking adenosine receptors, anti-inflammatory effects from chlorogenic acids, and behavioral benefits from reduced fatigue. Effects were stronger in men, while women metabolize caffeine more slowly, potentially altering the benefit. The study is observational, so it cannot prove causation or replace standard mental-health care such as sleep, exercise, diet, and social connection.