You are restless, anxious, nervous, distracted; it is late at night and you just can’t sleep. Have a cup of tea. You drank four cups of coffee before a big exam and now you can’t concentrate on anything because you keep shaking and your head hurts. Drink a cup of tea. If modern studies are true, tea might actually act as an anti-anxiety, anti-stress compound, with sedative qualities and the ability to help you focus on the task at hand. Have we found the new non-prescription miracle drug for all the world’s ills? That might be a stretch, but my recent investigation suggests that we need to rethink the idea of caffeine content in tea, and make room for a more complex treatment of tea than caffeine levels measured in milligrams.

My investigation began with a contemplation of the concept of chaqi (chah-chee). In China, my tea mentors often talk about this mysterious chaqi.  This idea is based in a very different concept of wellness related to the flow of vital energies through the body.  A tea with good chaqi is said to promote this flow of energy, and enhance spiritual attainment to the sensory experience of tea drinking, promote heightened contemplation and meditation, etc.  When you ask what causes this feeling and how exactly it effects the body, there is a lot less clarity.

I asked my mentors if chaqi is the same thing as caffeine, and they emphatically denied that possibility.  Caffeine can be found in soda, coffee, etc, but there is a very specific feeling of alertness that many claim only tea can bring about. Is there something about tea that gives it special calming and sedative effects that other caffeinated beverages lack?  For the longest time, I thought that it was just the ritual of sitting down and sipping tea that produced the psychological effect of well-being.  The social interaction of a tea tasting ceremony may actually raise levels of seratonin in the brain.   If this is the case, then it made sense to me that even consuming a caffeinated beverage could have a calming effect in the right social context.

While the social context is important, and the reduced stress and anxiety of tea drinking in a group cannot be ignored given the medical proof that such activity may in fact make you happier, that couldn’t be the whole story.  I feel great even when I drink tea by myself, even if the calming effects are not as strong.  To further this investigation, I looked into what chemical compounds tea has that other foods and beverages do not seem to contain at the same levels.

The most intriguing thing I found that is the role of a complimentary compound in tea separate from caffeine: L-theanine.  A 2012 study showed promising results indicating that while the alertness you get from caffeine is not diminished by L-theanine, you sleep more solidly and less fitfully when you drink tea (which contains L-theanine and caffeine) than you would from a beverage that contains only caffeine (like coffee).  This study was conducted by measuring slow-wave sleep in rats.  Caffeine dramatically reduced slow-wave sleep while a combination of L-theanine and caffeine counteracted this decrease significantly.  Tea is one of the most common substances in which both caffeine and L-theanine occur naturally.

Another study in 2012 was conducted with human volunteers which measured brain wave patterns of participants administered caffeine, L-theanine, both and neither.  Only those administered with both caffeine and L-theanine together showed an increase in brain wave activity, and a decrease in error rate on sustained monotonous activity.

Another study in 2010 compliments the findings of the 2012 experiment by measuring cognitive performance, mood, and blood pressure with caffeine, L-theanine, and both together.  The group given both caffeine and L-theanine showed significantly higher accuracy and reported much lower levels of tiredness, and higher levels of alertness than either group given one compound or the other.  Caffeine and L-theanine seem to work together, enhancing the good effects of alertness and sustained attention while working synergistically to reduce the negative effects of fitfulness and restlessness commonly felt in caffeine.  Tea was often used in early history by monks practicing meditation as an aid to concentration.  It appears that modern studies confirm that tea uniquely boosts cognitive function without the same level of caffeine-induced overactivity.

In fact, people suffering from anxiety, restlessness and overstimulation may benefit by drinking tea to produce a greater sense of calm and focus if these recent studies hold true.

Lab tests also introduce the possibility that the polyphenol EGCG present in tea may actually act as a sedative, counterbalancing the stimulant quality of caffeine.  EGCG administered to chicks lowered social separation stress and increased sleep by interacting with the GABAA receptors in the brain.  The same effect was observed in mice in a 2006 study indicating that the powerful anti-oxidant EGCG found in tea may actually directly work to counteract the stimulant properties of tea’s naturally occurring caffeine.

The balance of the synergistic alertness-boosting, anxiety-reducing effects of caffeine and L-theanine combined with the mild sedative effect of EGCG antioxidants may in fact be the answer to our search for chaqi.  Of course, the Chinese concept of chaqi is holisitc, and takes the social act of tea drinking, and enforced meditation into account, but in our search for the chemical contributors to chaqi, this is the strongest case I have seen so far that can be applied to any kind of tea, from green tea to pu’er.

The important lesson to take away from this is that as a tea buyer you should pay more attention to a tea’s specific effect on your body than to the stated caffeine content.  A tea might be very high in caffeine, but also high in EGCG and L-theanine, which in the end may contribute to a more calming effect than a stimulant effect.  Predicting the exact effect a tea is going to have becomes more complex task than measuring caffeine.

Generally it seems that black teas have been measured to contain more L-theanine than green tea, but the question to be asked is which black teas? A tea bag is very different from looseleaf Yunnan black, or Fujianese black, or even a Darjeeling or Assam.  No conclusive evidence can be presented on the most EGCG-rich teas either.  It all depends on processing technique, region, and more.  A 2010 study that attempted  a more comprehensive sampling of white and green teas from different regions found great overlap in the amount of EGCG antioxidants in each, dismissing the idea that green tea is king for antioxidant levels.  This also means that we are going to have an even harder time mapping the physiological effects of a tea, or predicting the chaqi until we just give it a try.

All of this investigation has helped me to better understand what an incredibly complex plant tea is.  In addition to the almost infinite synergistic effects of flavor, texture, aroma, and aftertaste, it seems that the physiological possibilities for tea are just as rich.  Unless you are extremely sensitive to caffeine, don’t be afraid to experiment with different kinds of tea and different brewing techniques at different times of the day to see how you feel.  Don’t be surprised if you get the feeling of chaqi yourself.