Caffeine (Methylxanthine)

Caffeine, a type of methylxanthine, is a natural stimulant commonly found in coffee, tea, chocolate, and certain energy drinks. It works by blocking a brain chemical called adenosine, which promotes sleepiness, thus increasing alertness and reducing fatigue. Caffeine can enhance focus and energy levels, making it a popular choice for boosting productivity. However, excessive consumption may lead to side effects like jitteriness, anxiety, or trouble sleeping. Generally, moderate caffeine intake is considered safe and can even offer some health benefits when enjoyed responsibly.