Coffee (Caffeine)
Coffee: 95mg caffeine/cup. Faster onset. Higher peak. No theanine. Can cause jitters, anxiety, cortisol spike at high doses or on empty stomach.
Green Tea (Caffeine + L-Theanine)
Green tea: 30mg caffeine + 20mg L-theanine. Slower, smoother onset. Theanine increases alpha brain waves → "calm alertness" without jitters. Better for sustained attention.
Verdict
Coffee for raw energy, morning wake-up, pre-workout. Green tea for sustained focus, study sessions, anxiety-prone individuals. Or: coffee now, green tea afternoon.
Best choice: depends on goal