Caffeine is a bitter substance found in coffee, tea, and several other plants. It belongs to the class of substances known as stimulants, which operate by stimulating the central nervous system. This results in increased alertness and reduced fatigue. Caffeine can also enhance cognitive performance and is often used to increase wakefulness. For more information and answers to other frequently asked questions, visit our FAQ page . Discover more tips, advice, and interesting articles about our products and related topics on our blog .