Well fist off creatine is not an active chemical, I think someone already mentioned its simply a moderatley important part of the ATP procces, well the anerobic resperation anyways. Its comverted into Creatine phosphate which essentially enhances the recyling properties of ADP (diphosphate into triphosphate, your body loses a phospate to make heat)ito ATP
Thimg with creatine is, the loading phases are total bogus, depending on your genetics and size you can only absorb so much, and it AINt 20 grams a day. I could link you a study with loading and non loading of healthy men and after 30 days serum levels were identical except hte non loading phase had consumed about 25% of the loading group. Also creatine manufacturing/storage is stressfull on the kidneys.
Also, it takes about 60 days to reach peak serum levels even taking up to 15 grams a day and as low as 3. It also takes about 30 days for levels to return to baseline after ceasing. SO if you think you notice an immedeate effect its placebo. Also, exercising doesnt "use up' creatine, its not like a calorie.....]
Also, there are several other pathways other than phosphates which work fine for anerobic resperation, in fact creatine supplimentation is hardly required, much less important that BCAA, glutamine and protein, if you insist Id stay below or at 5 grams per day, anymore and you have just increased the value of your urine, grats.
Also someone mentioned increased actual max lift increases? That has been found but its purely nerological, your body already has creatine phosphate in plentiful ammounts stored away, unless your a vegan and vegitarian and you dont consume any animal tissue or suplimment. More creatine means faster recovery it also yes does increase reps with a given weight only because the muscle can work longer because it has deeper reserves of phospates inside it, thats over simplified. But there is no legal suppliment you can take and walk in and lift more weight instantly. The bloating and cramping can be solved with keeping the ammount at or under 5 grams, and staying hydrated.
Also dont use any esters or liquid forms, monohydrate is still the best and cheapest.