Of them, green tea gets a lot of credit for being high in antioxidants and giving the brain a potential boost in cognition. Caffeine is a natural stimulant that affects the central nervous system.
Although caffeine is generally safe in low-to-moderate amounts, high levels of consumption may lead to unpleasant and even dangerous side effects. Coffee and tea are healthy beverages. However ...
L-theanine is also present, in lower concentrations, in black tea. There’s less research on the effects of coffee on stress, but researchers have found moderate to high amounts of caffeine are ...