c It is found in high levels in tea, and is believed to contribute to the relaxing properties that accompany its consumption. It has been shown to increase the levels of GABAs (neurotransmitters) and A waves in the brain, causing sedation without the appearance of drowsiness as it stimulates the alpha brain waves responsible for the condition known as "stimulus calm". Preliminary research shows that Theanine may help with cardiovascular function, deep sleep success, improve concentration, reduce nervousness and possibly blood pressure.