If you look at the ingredients list for any fat burning product, chances are that green tea will be on there.
This is because green tea has been shown to increase fat burning and boost metabolism in human controlled trials. In one study in 10 healthy men, green tea increased energy expenditure by 4%. Another study showed that fat oxidation was increased by 17%, indicating that green tea may selectively increase the burning of fat.
However, some studies on green tea don’t show any increase in metabolism, so the effects may depend on the individual.