Caffeine is one of the most widely consumed psychoactive substances in the world, valued for its stimulating effects on the brain and body. To understand how caffeine works, it is necessary to examine its biological mechanisms and the genetic factors that influence caffeine sensitivity. What is Caffeine? Caffeine is a naturally occurring central nervous system stimulant in the methylxanthine class, a group of drugs with stimulatory and bronchodilatory (or the ability to open