But green tea has caffeine?!?!
L-theanine is an amino acid in green tea which may actually act against the stimulating effect of the caffeine. It is believed to encourage alpha brain waves which creates deep relaxation (as does meditation). It may also interact with neurotransmitters in the brain, which may allow L-theanine to contribute to mood regulation.
Consider giving green tea a try. I’m currently experimenting with TAZO Zen Green Tea. Pay close attention to how it may affect you. All chemical substances, including both L-theanine and caffeine affect everyone differently.