L-theanine, which occurs naturally in tea leaves, has been shown to be an amazingly effective, fast acting anti-anxiety agent. Research on human volunteers has reveals that L-theanine works in several different ways to produce a sense of relaxation within approximately 20 to 40 minutes after ingestion.
One mechanism involves L-theanine's ability to increase the calming alpha brain waves in humans while decreasing the brain's active beta waves.(1) This helps create a state of deep relaxation and mental alertness similar to what is achieved through meditation and some forms of yoga.
Another reason theanine is an effective anti-anxiety agent is due to the fact that it easily gets crosses the blood-brain barrier where it gets converted into GABA (gamma-aminobutyric acid) which is the primary calming neurotransmitter in humans.
A third way theanine produces calming effects is that it blocks the binding of the excitatory neurotransmitter glutamic acid to the glutamate receptors in the brain.
So, in summary, we have a natural herbal compound that gets absorbed, easily enters the brain and gets converted into GABA, it increases alpha and decreasing beta brain waves, and it also lowers the activity of excitatory glutamate receptors. Each of these functions contributes to theanine's calming anti-anxiety effects. Whereas other relaxing products like kava kava, valerian and St. John's Wort can cause drowsiness, theanine does not cause drowsiness, sedation of impair an individual's motor skills.
Anxiety cause sleep problems for many people. Although theanine does not cause drowsiness, its anti-anxiety effects help many people with anxiety get to sleep easier and have better quality sleep.