Creatine is a nitrogenous organic acid that acts as a phosphate transport molecue. It works very well for strength training by providing fast twitch muscle fibers with phosphate groups for making ADP into ATP, and ATP is energy. Fast twitch fibers, as many of you already know, does not go through the complete Krebs Cycle and does not use oxygen for energy. It uses glycogen (sugar) and creatine phosphate locally stored in muscle fibers for energy. Creatine is natrually produced by the liver and stored in the fast twitch muscle fibers. Some small amounts are stored in the brain, heart, and testes for sperm cells.
BUT if you do not train with heavy weights to stimulate ONLY the fast twitchy fibers, you are not going to see much gains at all. SO for those who do the regular 10 reps, that is not heavy and intense enough for full recruitment of fast twtich fiber, but rather shared with slow twitch fibers, and creatine does NOT increase any endurance. Slow twitch fibers rely on locally stored myoglobin for energy.
HOWEVER, incorrect supplimentation of creatine can be a problem... Creatine is a compound made from various amino acids binded with rather weak ionic bonds, therefore can be altered easily with changes in temperature and PH. So if creatine is mixed in a solution that is hot, acidic, carbonated (CO2 H2O = H2CO3 or carbonic acid), caffinated, it turns into CREATININE, a waste product for the kidneys... That is why creatinine is a measure of healthy kidney fucntion.
Creatine is NOT creatinine. Please do not get the 2 confused.
So the research studies on creatine showing limited effectiveness need to be critcally evaluated if the study subjects were training with heavy and intense weight training, preferably under 10 reps.
Some research also show prolonged supplimentation of exogenous creatine can decrease your body's own production of endogenous creatine...
One very important note: Since creatine is eventually broken down into creatinine to be excreated by the kidneys, if you already have a high level of blood creatinine level, that is an indication of impaired kidney function. Then DO NOT take creatine...
But if you have no kidney issues and wish to take creatine, it would do you no good with muscle strength building if you change creatine into creatinine right there in your drink... You just gave your kidneys more work to do without getting any benefit to your muscles..
AND there is a common misconception about creatine causing dehydration because more water is displaced in the muscle tissue locally. Yes, there is more water in the muscle tissue locally but this is NOT a displacement. Yes, there is more water in the tissue to reach osmotic equilibrium and possibly do add a bit more mass to tissues and space for contractile activity, but the dehydration is caused by the flushing of creatinine byt the kidneys. Anything you need to flush out from the kidneys, you need water to do that...
But creatine DOES work quite well if your GI track can tolerate it, and that you take it in a correct form, AND you train for the appropriate muscle fibers to take advantage of it, and drink lots of water.
It does not work well if you do not do any of the above correctly..