high purity l-theanine, one of the strongest tablets available in the uk,we insist on the l- not d form for better absoprtion,fantastic reviews from happy customers , tablets made to gmp standardseveryone knows that \'a nice cup of tea\' is the best thing for someone who has had some kind of shock or stressful ordeal. no other hot drink seems to offer this kind of support so there must be something in tea that has this calming effect. tea certainly contains a surprising amount of caffeine and yet is not generally considered as a stimulant in the way coffee is. some researchers think that this may be because tea contains something else - in effect cancelling out the caffeine. the mystery ingredient in tea is now thought to be an amino acid called l-theanine. when l-theanine has been given to people in clinical studies many of the positive effects of tea can be reproduced. nature\'s best l-theanine is the purest form available and is the one used in clinical studies. l-theanine is not known to be addictive and does not cause drowsiness.