Caffeine is a natural stimulant most commonly found in coffee, tea, soft drinks, and chocolate. It belongs to a class of compounds known as xanthines and is a psychoactive substance that affects the central nervous system. Caffeine works primarily by blocking the action of adenosine, a neurotransmitter that promotes sleep and relaxation, thereby increasing alertness and reducing the perception of fatigue.
Caffeine is widely consumed around the world for its stimulating effects. While moderate consumption is generally considered safe for most people and can even have some health benefits, excessive intake can lead to negative effects such as insomnia, jitteriness, increased heart rate, and anxiety. People can vary in their sensitivity to caffeine based on genetic factors, tolerance levels, and individual health conditions.