Caffeine is an alkoid and is found in guarana, kola nuts, coffee, tea and cocoa beans. It is the most popular drug in the world and is a powerful stimulant to the central nervous system. After caffeine is consumed, it is absorbed into the bloodstream and other body tissues. It takes about half an hour to experience peak concentration in the body. Take 1 tablet no more than every 3 to 4 hours up to a maximum of 1000 mg (5 tablets) in 24 hours.