... it is an enzyme that is naturally produced in your body. it does have wierd effects: much higher rate of dehydration, much higher impact on imune system and so on. addtionally it allows muscules to intake more watter thus causing size gains in a prompt manner... these gains go away as soon as you stop taking creatine. Its also an expensive habbit and from my experience, unless you are into serious body building, waste of money as its lke putting rocket fuel into a cat. will go fast and in circles but zero usefulness.