This article has " resurfaced" on am. It was first published a few months ago. And because im Brazilian I took a particular interest on this research. They drank a green tea powdered drink, containing 189mg polyphenols and apprix 27 g of caffeine. The capsule extracts are usually 500mg indeed but its standard around 80_90% polyphenols and 50% egcg so caps are much stronger. Also good to mention, taking from other researchers green tea is most effective when taken with caffeine