Both tea and coffee have caffeine, but the actual amount can vary widely.
A recent study found that tea and coffee offered similar effects on alertness and cognitive performance, but that tea had one big advantage over coffee: It had enough caffeine to aid performance, but not so much that it disrupted sleep.
STRESS LEVELS / RELAXATION
For those that are looking for a smooth and gentle beverage that might even melt some stress away, then look no further than tea. Studies have found that when people are stressed, drinking green or black tea can help them feel more relaxed and lower their levels of cortisol, the stress hormone. Studies suggest that this is in part due to L-theanine, a compound found in tea – particularly green and black teas – that seems to promote relaxation.
But when you compare coffee to tea, while coffee has higher levels of caffeine that can stimulate cortisol levels and elevate your mood, the reality is that too much coffee can also cause jitteriness, anxiety and insomnia when consumed in excess.