What do you think about coffee?

Coffee can be beneficial for alertness, mood, performance, and health, but how much you drink and when you drink it matter—and caffeine affects people differently.

• Caffeine and sex hormones: Moderate caffeine intake may raise sex hormone-binding globulin slightly, which can modestly lower free testosterone and free estradiol; the effects described were relatively small. 1
• Performance and mood: Caffeine can improve mental and physical performance, including reaction time, memory, coordination, and exercise-related measures. Regular intake is also associated with fewer depressive symptoms, though it is not a treatment for severe depression. 2 3
• Sleep timing: Caffeine later in the day can impair sleep quality and reduce deep sleep, even when it doesn’t stop someone from falling asleep. Sensitivity varies, so timing needs to account for the individual. 4
• Regular use and performance boosts: With regular caffeine use, the added cognitive or physical boost may be limited unless a person abstains for a period; many studies compare caffeine with a withdrawal state. 5
• Benefits beyond caffeine: Coffee contains antioxidants, and decaffeinated coffee retains many of the health benefits associated with coffee, suggesting benefits beyond caffeine’s stimulant effects. 6

In short, coffee can be a useful part of a routine, but moderation and sleep-friendly timing are important.