Green tea

Green tea is another natural source of caffeine. It is particularly well-liked in Asian nations. Green tea is more than just a hydrating beverage, it is touted to be one of the healthiest beverages on the planet.

Studies have revealed that theanine, an amino acid found in green tea, acts on the hippocampus in the brain and reduces stress in both people and animals. Further research is required, however, a 2017 study highlighted the possibility that green tea's theanine and caffeine content may enhance cognition and brain function while also lowering anxiety. Half as much caffeine as a cup of coffee is present in an 8-ounce (240 mL) serving of green tea, which contains between 30 and 50 mg of caffeine. The age of the leaf affects the caffeine content in green tea. Less caffeine is present in older leaves than in younger leaves.