11 Evidence-Based Facts: Coffee vs Tea Health Benefits Compared

5. Caffeine, energy rhythm, and focus

The caffeine story differs between the two drinks and alters how you feel. An eight-ounce serving of green tea typically contains about 15–48 mg of caffeine, while coffee provides much more per cup; public guidance often references a 400 mg per day upper limit for most adults. Tea’s L‑theanine slows caffeine’s spike, producing calm concentration with less jitteriness or crash—nice for studying or when you need steady mental energy across the afternoon. Coffee gives a stronger, faster boost that many people prefer for early-morning alertness or quick performance tasks. If you’re sensitive to caffeine or prone to sleep trouble, spacing coffee earlier and choosing tea later in the day is a practical approach. Tuning timing to your daily cortisol and sleep schedule helps preserve the benefits without sabotaging rest.