Researchers analyzed 24 different products for both strength and purity, evaluating each product’s level of EGCG, the dominant antioxidant in green tea that’s linked with so many health perks. “For the brewable teas, EGCG quantities ranged from 25 mg per serving to 86 mg per serving per product, which makes a big difference in how much you have to drink to get those benefits,” says Cooperman.