While both coffee and tea contain caffeine, L-theanine is found naturally in green tea and, contrarily, is absent from coffee. We, therefore, may use the elusive amino acid's presence or lack thereof as a point of comparison between our competing beverages. Caffeine on its own is perhaps most noticeably associated with its neuro-stimulating effects, increased alertness, and cognitive performance at the expense of elevated heart rate and blood pressure. You may be content to accept these side effects as a coffee drinker. HOWEVER, there is another path, offered by our favorite beverage of tea. L-theanine, once again found naturally in tea, antagonizes caffeine in such a way as to reduce the negative effects while boosting the positive. L-theanine regulates the central nervous system, increasing the release of dopamine, inhibimating..inhibiting glutamate reuptake, decreasing norepinephrine, and increasing serotonin. That's right, L-theanine antagonizes caffeine, lowering blood pressure while coffee continues to elevate and elevate again. Further, L-theanine increases alpha brain wave activity, which is associated with creativity, improved learning, and decreased anxiety. Tea bests coffee in terms of variety, taste, and health. But you need look no further than L-theanine to prove tea's dominion over coffee.