CaffeineCaffeine is the psychoactive substance most consumed by human beings throughout the world (Reid, 2005). This report will detail its natural origins, its chemical structure (as well as that of similar substances), and the methods and dosages in which it is transformed into its usable form. Additionally, this report will detail the various biological pathways of caffeine in the human body, including access to the brain and various neurotransmitter pathways. Caffeine is a chemical found naturally in more than 100 plant species around the world (Steffen, 2000). Perhaps the best known of these plants is the coffee plant, whose small seed (commonly called a “bean”) is roasted and then ground into a fine powder (Weinberg and Bealer, 2001). Caffeine also occurs naturally in cocoa beans, tea leaves, kola nuts, gurana seeds and mate. Some of these plants, like tea, actually contain a separate but similar chemical to caffeine (i.e. theophylline); these chemicals will be discussed in more detail in the chemistry section (Steffen, 2000). Caffeine is chemically known by two names. The first is 1,3,7-trimethylxanthine; the second is 3,7,-Dihydro-1,3,7-trimethyl-1H-purine-2,6-dione. Historically, caffeine has also been known as methyltheobromine, as well as theine (Weinberg and Bealer, 2001). The chemical formula for caffeine is C8 H10 N4 O2. The molecular weight of this chemical is 194.19 atomic units. Its composition is as follows: 49.5% carbon, 5.2% hydrogen, 28.9% nitrogen and 16.5% oxygen. Caffeine melts from a solid hexagonal crystal at 238 degrees Celsius (Karch, 1993)....... middle of paper...... Parliament, C.Ho and P. Schieberle (Eds.), Caffeinated Beverages: Health Benefits, Physiological Effects and Chemistry (p. 46-53). Washington, DC: American Chemical Society. Spiller, G. (1998). Basal metabolism and physiological effects of methylxanthines. In G. Spiller (Ed.), Caffeine (pp. 225-231). New York: CRC Press. Steffen, D. (2000). Chemistry and health benefits of caffeinated beverages: overview of the symposium. In H. Parliament, C.Ho & P. ​​Schieberle (Eds.), Caffeinated beverages: health benefits, physiological effects and chemistry (p.2-8). Washington, DC: American Chemical Society. Reid, T. (2005). Caffeine: what's the buzz? Why we love caffeine. National Geographic, 207, 1, p.2-33. Weinberg, B. and Bealer, B. (2001). The World of Caffeine: The Science and Culture of the World's Most Popular Drug. New York: Routledge.