L-theanine is a unique amino acid found primarily in green tea. Researchers have determined L-theanine to be the central reason why tea has always been known to promote relaxation while still enhancing a sense of acute awareness.
In one experiment, 50 women volunteers were divided into high-anxiety and low-anxiety groups. Each group was given either 50mg or 200 mg of L-theanine once a week for two months. Researchers concluded that L-theanine rapidly enters the system when ingested (within roughly 40 minutes) and that it heightens the index of the brain wave which is known to be linked to a state of relaxed wakefulness. Researchers also explored whether the response to L-theanine might be influenced by the level of anxiety found in the test subjects. As might be expected, the greatest degree of change was found in those manifesting high anxiety.
Various other experiments have determined that L-theanine influences the levels of the neurotransmitters dopamine and serotonin in the brain, positively affecting learning capacity. L-theanine also appears to protect against certain so-called "excitotoxins." It modulates the motor-stimulation associated with caffeine, and it inhibits some of the actions of norepinephrine in the central nervous system. In tests with gerbils, L-theanine also protected neurons from ischemia, a condition that can result in the death of these cells.
Suggested Use (Adults): Take one capsule daily without food, or as directed by a qualified health care practitioner.