Boost your Immune system, digestive system or energy throughout the day! Oolong teas contain 30-50mg of caffeine to give a large boost of energy to your afternoon. Green teas contain about 30mg of caffeine to give you a slight energy boost with mental clarity and alertness without any peaks or crashes. White tea contains less than 10mg of caffeine and allows for quiet meditation and focus. Oolong and Pu- erh teas boost fat metabolism and digestion. Green, chamomile, hibiscus, lemongrass and orange teas boost the immune system.