Tea is often advertised with abstract health claims that may have effects only statistically significant or even completely exaggerated. The most significant effect of tea is a general improvement of our feelings after drinking tea. Tea gives relaxed feelings, physically and / or mentally, comfortable and a clearer state of mind.
Tasty tea is an easy substitute for other drinks and treats, which is maybe where tea's biggest health benefits come from.
Tea contains three particularly important psychoactive substances. Caffeine refreshes, removes drowsiness as well as improve the brain's performance, but in tea, interaction of caffeine with other substances makes caffeine releasing a milder and slower process, comparing to the caffeine in coffee. Theanine relaxes, reduces stress, gives a meditative state of mind, and elevates the ability to concentrate and boosts the mood. EGCG, or epigallocatechin gallate, reduces anxiety as well as soothe. The interaction of these (and other) substances depends on the quantities. Some teas are invigorating, while others are more
soothing and undisturbed, even if the caffeine content is the same.
A gram of dry tea leaf contains about 15 to 35 mg of caffeine, and brewed tea contains about ¼ – ½ caffeine comparing to the average coffee. The amounts of caffeine and other substances are most affected by the quality of a single tea
variety, growing environment, cultivation method and leaf processing: quantities cannot be straightforwardly generalised by tea categories. The amount of caffeine and theanine in the quality of tea is most likely to increase when there's a large proportion of buds. In the case of theanine, early picking and shading will increase the quantity of the substance.