PRODUCT DESCRIBTION Green Tea L-theanine is extracted from green tea(Camellia sinensis). Natural L-theanine is a unique amino acid found almost exclusively in tea plants. Early in 1985, America Food and Drugs Administration has certificated that L-theanine is Generally Recognized as Safe(GRAS). and It hasnt limited the dosage. FUNCTION 1. Mitigating stress and anxiety 2. Preventing parkinsons disease; 3. Alleviating PMS(premenstrual syndrome)Symptoms in Women; 4. Improving learning ability and memory; 5. Enhancing the efficacy of anti-cancer drugs; 6. Food grade, pure natural, free sample.