People who supplemented 300 mg EGCG (found in green tea) daily experienced increased calmness and less stress and had an increase in alpha, beta, and theta activity in certain brain regions compared to people taking a placebo.

This trial was a double-blind placebo-controlled trial that found that those taking EGCG did experience less anxiety and felt calmer compared to those given a placebo. The EGCG group also had an increase in several different types of brain waves including those activated during mediation in the frontal gyrus and medial frontal gyrus brain regions.