The most common sources of caffeine for human consumption are the tea leaves of the Camellia sinensis plant and the coffee bean, the seed of the Coffea plant. Some people drink …

Mar 21, 2025 · What is caffeine? Caffeine is a type of drug called a stimulant, meaning it increases chemicals in your brain called neurotransmitters.

Dec 2, 2025 · Caffeine, nitrogenous organic compound of the alkaloid group, substances that have marked physiological effects. Caffeine occurs in tea, coffee, guarana, maté, kola nuts, …

Feb 6, 2025 · Find out how much caffeine is in coffee, tea, soda and energy drinks. You may be getting more caffeine than you think you are.

Caffeine is a natural chemical with stimulant effects. It is found in coffee, tea, cola, cocoa, guarana, yerba mate, and over 60 other products. Caffeine works by stimulating the central...

Although we tend to associate caffeine most often with coffee or tea, the research below focuses mainly on the health effects of caffeine itself. Visit our features on coffee, tea, and energy …

Nov 3, 2025 · Caffeine is a stimulant and the most commonly used drug in the world. Benefits can include increased alertness, energy, and concentration. However, it can also lead to insomnia …

Apr 1, 2025 · Caffeine is a substance that is found in certain plants. It can also be man-made and added to foods. It is a central nervous system stimulant and a diuretic (substance that helps rid …

May 18, 2023 · Caffeine is a natural stimulant consumed throughout the world. This article reviews caffeine and its health effects, both good and bad.

Nov 19, 2025 · Caffeine is a central nervous system stimulant that can improve sports performance and aspects of cognitive function. Caffeine or caffeine-containing beverages are …