Oolong is the tea variety with higher L-theanine. In Fugi, where that tea is from they rebrew their tea 4-5 times and they feel 3 & 4 are the best ones as they have more relative Theanine. I've been drinking Yerba Mate stacked w Oolong for 15 years now. Key to tea is careful brewing w attention to temp and duration. One last warning many modern tea bags are plastic, avoid those.