What is Green Tea Extract? Green Tea Extract is a high strength, naturally occurring plant extract traditionally sourced from China. Why use Green Tea Extract? Green Tea Extract is a premium quality capsule providing 450mg of Green Tea Extract, 427mg of polyphenols and 11mg of caffeine. Caffeine helps to increase alertness and improve concentration while also contributing to an increase in endurance capacity and performance. Who can benefit? These easy to consume capsules make Green Tea Extract the ideal supplement to be taken as part of a varied and balanced diet and a healthy lifestyle.