Ingredient Type: Amino acid
Also Known As: Gamma-ethylamino-L-glutamic acid, γ-L-Glutamylethylamide
L-Theanine is a non-essential amino acid found primarily in tea leaves (specifically Green Tea), but it has also been isolated in mushrooms. It was discovered in green tea in Japan in 1949 and has since become a popular additive to foods. It is believed to calm stress, boost mood, and improve cognitive performance.
L-Theanine has a chemical structure very similar to glutamate, an amino acid that occurs naturally in the body and helps transmit nerve impulses in the brain.
L-Theanine is used in health supplements today to promote relaxation and focused concentration.
WHAT DOES SCIENCE TELL US?
Cognitive Performance: Preliminary clinical research shows that taking theanine 100 mg prior to cognitive testing reduces the rate of errors compared with placebo in healthy adults.
Stress: One clinical study shows that taking L-theanine (Taiyo Kagaku) 200 mg prior to a psychological exam reduced tension-anxiety and prevented blood pressure increases caused by psychological stress. Other preliminary clinical research shows that pharmacy students taking theanine 200 mg twice daily for one week prior to and for the first 10 days of a pharmacy practice period had decreased subjective stress scores compared to placebo.
Theanine is possibly safe when used orally, short-term. Theanine has been used safely once per week for 3 weeks. It is not known if use for longer periods of time is safe. Theanine is sold in the United States as a dietary supplement and has been granted GRAS (generally recognized as safe) status for food by the Food and Drug Administration. Few adverse reactions have been reported. Adverse reactions recorded in human studies using tea extracts include a headache, dizziness, and mild GI symptoms.
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