Caffeine

Caffeine is the most common natural nootropic or cognitive stimulant that has been used for several centuries. Almost 80% of the world’s population consumes products that contain caffeine in order to stay alert and productive. Besides coffee, other foods that are high in caffeine content include chocolate, ice cream, frozen yogurt, breakfast cereals, pudding, cocoa, soft drinks, tea brews, and protein bars. Nowadays, caffeine is also available in the form of supplement pills.