Caffeine

caffeine

Caffeine is a natural stimulant found in plants such as coffee beans, tea leaves, and cacao. It works by blocking certain receptors in the brain, which reduces feelings of tiredness and helps you feel more alert and focused. People commonly consume it in drinks and foods to wake up, improve concentration, or boost physical performance. Its effects usually begin within 15–45 minutes and can last for several hours depending on the person and dose. Caffeine also increases heart rate and can temporarily raise blood pressure, so people with cardiovascular concerns often watch how much they consume. It can interfere with sleep when taken late in the day, making it harder to fall asleep or stay asleep. Sensitivity to caffeine varies widely—some people feel energetic after a small amount, while others experience jitteriness, anxiety, or stomach upset. Regular use often leads to tolerance, and stopping suddenly can cause withdrawal symptoms like headaches and irritability, so it matters to know your personal limits and how it affects your body.