Caffeine is a stimulant and alkaloid derivative of xanthine (other “xanthines” include theobromine). When ingested, it takes effect quickly as an adenoisine receptor antagonist (i.e. blocking). Caffeine reaches peak blood-levels within 30-60 minutes and has a half-life of 3 to 5 hours.
Coffee accounts for 54% (ref?) of caffeine consumption in the world and is made from roasted, dried and ground beans of a plant from genus coffea, native to tropical Asia and tropical & southern Africa. There are more than 120 different coffea species, with Coffea Arabica and Coffea Canephora (“robusta”) accounting for the majority of global coffee production.
(I probably drink too much coffee. Something I should think about in my personal development?)