Do you drink several cups of coffee each day to keep yourself awake and alert? You might be better off switching to green tea. Coffee contains quite a bit of caffeine, which can leave you feeling jittery, anxious and exhausted by the end of the day. Green tea also contains caffeine but in much smaller amounts. Green tea also contains the amino acid l-theanine. L-theanine increases the activity of the inhibitory neurotransmitter GABA, which has calming, anti-anxiety effects. It also raises dopamine and the production of alpha waves in the brain. This is because l-theanine is able to cross the blood-brain barrier. Green tea won't sedate you; it helps to keep you feeling calm, focused and alert. The antioxidants in green tea may also help to reduce the risk of cancer and heart disease. If you are prone to experiencing anxiety, try replacing your cups of coffee with green tea for a week and see if you benefit. Reference