Re: What is Creatine? Is it safe? How many kinds of creatine are there?

Hello Phillip,

Creatine is used in muscle cells to store energy in the form of creatine 
phosphate.  We normally get creatine from our diet, so the same benefits 
can be gained from eating the right diet.  Red meat contains high levels of 
creatine.  The theory behind using creatine as a nutrient supplement is 
that by increasing the levels of creatine in the body this will increase 
the levels of creatine phosphate in the muscle increasing the store of 
energy.  The different products that you mention all contain creatine, 
maybe in slightly different forms and also possibly containing other 
additional supplements.  I doubt that there is any real difference between 
any of these compounds except probably in cost.
I have had a look through the most recent published literature on this and 
the evidence is far from convincing.  Here are some quotes that I have 
taken from some of the articles that I have seen  on this.

TI: 	Effects of creatine supplementation on exercise performance.
AU: 	Demant-TW; Rhodes-EC
SO: 	Sports-Med. 1999 Jul; 28(1): 49-60
"Creatine supplementation of 20 g per day for at least 3 days has resulted 
in significant increases in total Cr for some individuals but not others, 
suggesting that there are 'responders' and 'nonresponders'."
"Creatine supplementation does not appear to aid endurance and incremental 
type exercises, and may even be detrimental. Studies investigating the 
effects of creatine supplementation on short term, high intensity exercises 
have reported equivocal results, with approximately equal numbers reporting 
significant and nonsignificant results. The only side effect associated 
with creatine supplementation appears to be a small increase in body mass, 
which is due to either water retention or increased protein synthesis."

TI: 	Potential side effects of oral creatine supplementation: a critical 
review.
AU: 	Juhn-MS; Tarnopolsky-M
SO: 	Clin-J-Sport-Med. 1998 Oct; 8(4): 298-304
"Creatine supplementation results in weight gain due to water retention, 
which may impede performance in mass-dependent activities such as running 
and swimming. Although short-term use (fewer than 28 days) at recommended 
doses has not been shown to cause significant adverse effects, the studies 
on which this is based involved small numbers of subjects, and none of the 
studies provided a sample size calculation. Furthermore, despite the fact 
that creatine is normally found in cardiac muscle, brain, and testes, these 
areas remain essentially unstudied with respect to oral creatine 
supplementation. Future studies should include large randomised controlled 
trials evaluating the short and long term effects of oral creatine 
supplementation on the renal and hepatic systems, as well as the many other 
organ systems in which creatine plays a metabolic role."

In summary for short term high energy exercise, e.g. weight training, there 
may be some benefit in some individuals, however in endurance training 
creatine supplements are not likely to have any benefit.
How safe creatine supplements are has not been fully tested. In the short 
term they probably have few detrimental side effects but in the long term 
effects are not known.

It is also important to bear in mind that creatine is moved into the cells 
by special creatine transporter molecules in the cell membrane.  If there 
is a prolonged increase in creatine levels in the body then the number of 
these transporters is down regulated.  This means that over time the levels 
of creatine in the cell will decline back to normal levels and there is no 
net benefit over time to consuming creatine and there will be no benefit 
for long term creatine supplementation.

I hope that this has been of some use to you.

Dave