L-theanine, an amino acid found naturally in tea, may support the production of alpha brain waves and help to maintain a calm mood.* Alpha waves are associated with an awake-relaxed state, as opposed to beta waves, which are associated with feelings of restlessness and nervousness.1,2 L-theanine may help support relaxation in the midst of occasional stress, as alpha waves are indicative of a relaxation state.*1,2L-theanine may help maintain levels of the neurotransmitters dopamine, serotonin, norepinephrine, and glutamate that are already within the normal range, and is also metabolized into gamma-aminobutyric acid (GABA), a neurotransmitter that may help support relaxation and memory.3L-theanine can help temporarily promote relaxation and improve feelings of stress. In one study, a group of 50 female subjects, aged 18–22 years, were divided into a high-anxiety and a low-anxiety group. They received either water (as a control) or a solution containing 50 mg or 200 mg of L-theanine, and their brain waves were measured for 60 minutes afterward. Compared to controls, the group receiving 200 mg of L-theanine had a significant increase in alpha brain waves, indicating a relaxation effect.2 Similar results were seen in another clinical trial where 35 healthy young volunteers received 50 mg of L-theanine and had elevated alpha brain wave activity for 105 minutes afterward.1
