Caffeine is an alkaloid, naturally and abundantly present in several plants like coffee, tea, cocoa, guaranà, mate. Natural caffeine is obtained directly from its most common natural sources, coffee and tea, separated from it during decaffeination process and purifed.
As a supplement it is commonly used, besides its classical stimulating effect on central nervous system, for its thermogenic properties: it is able to boost metabolism and induce an oxidation of stored energy, thus promoting loss of weight.