Caffeine is a substance of plant origin. It occurs mainly in the leaves of tea tree and Yerba mate, cocoa seeds and fruits of the coffee trees. Caffeine is commonly used to stimulate the nervous system.
The main role of caffeine is the stimulation of the central nervous system, cerebral cortex, respiratory centre and vascular-motoric centre. Due to its ability to block adenosine receptors, it promotes the secretion of adrenaline, dopamine and serotonin, which results in the improvement of thinking processes, reduction in fatigue, increased mental and physical capacity, decrease in sleepiness and increase in thermogenesis.
It has been demonstrated that caffeine, in a form of pure supplements, is much more efficient than caffeine contained for example in coffee. Due to its stimulant properties, caffeine is recommended especially for people who are physically active or work mentally.