ECA STACK is a combination of ephedrine, caffeine and aspirin in a predetermined ratio. It causes your body to target specific fat cells to be burned for energy, all the while raising your overall metabolic rate and suppressing appetite. Each ingredient in this ECA stack works in conjunction with the next. Ephedrine works as a beta agonist and stimulates production of norepinephrine, as well as circulating it through adipose tissue by way of increasing cAMP levels. The caffeine and aspirin function to inhibit the body natural response to halt this cAMP production, thus prolonging the effects. ECA stands for Ephedrine, Caffeine and Aspirin; these compounds were found to be synergistic for fat loss, and isolating ephedrine from the Ephedra Sinicus plant and putting it into ECA appears to be quite an effective method of fat loss and neural stimulation.