Research has shown that the correct green tea extract dosage for fat loss is 300 mg. At a dosage of 300 mg of green tea extract per day in combination with exercise has shown a 30 percent increase in fat oxidation. What is even more astounding is when a dose of 200 mg is added in combination with green tea extract a 50 percent increase in fat oxidation has been observed by researchers. Researchers have concluded that there may be a synergistic relationship between the fat burning antioxidant EGCG and caffeine. Green tea extract and caffeine are a great fat burning stack.