May improve focus

Black tea includes caffeine as well as L-theanine, an amino acid that can boost alertness and attention. L-theanine boosts alpha activity in the brain, which leads to relaxation and improved attention. Because of the effects of L-theanine on the brain, studies have indicated that drinks containing L-theanine and caffeine had the greatest influence on attention. This might explain why, as compared to other caffeinated beverages like coffee, many people report having more consistent energy after drinking tea.

Participants in one short research examining the influence of black tea on cognitive performance drank either 250ml of black tea or water. Following that, they were tested on executive function, sustained attention, memory, and mathematical computations. Those who drank the black tea performed much faster on cognitive activities, had better memory and made fewer mistakes. According to the authors, even a tiny amount of black tea can increase cognitive processing. This makes black tea an excellent beverage for increasing energy and attention without consuming a lot of caffeine.