Re: What does creatine do to our cells and how does it affect homeostasis?

Dear Nikki,

The most straightforward answers to your questions that I could come up with are found in an online essay on Creatine: Historical and Practical Applications.  It may not be totally unbiased since it's published by The NutraSense Co., which also markets creatine as a dietary supplement.  Nevertheless, they appear to reinforce most of their claims with fairly sound biochemical evidence.  They also have a Creatine Research webpage available with links to the abstracts of relevant research reports in respectable scientific journals.  As a scientist, I would have preferred if they had referenced the most important pieces of evidence directly in the Creatine: Historical and Practical Applications essay, but it is more scientific support than most supplement suppliers are willing to provide.

In short, creatine serves primarily as an "energy buffer" for muscle cells, storing phosphorylation potential energy as a creatine phosphate reserve to be utilized when demand for muscle use increases above the typical range.  An excess supply of supplemental creatine would have little effect on our cells' homeostasis, since it would be rapidly cleared by the kidneys.  In fact, the main argument against supplemental creatine is that it's probably wasteful in most cases, since an adequate supply is typically synthesized by our bodies from the amino acid, glycine, & excess levels are not stored.  However, utilization of the creatine phosphate energy charge produces creatinine as its by-product, which cannot be recharged & is completely cleared by the kidneys.  So in those individuals who are rapidly building increased muscle mass &/or otherwise depleting their creatine phosphate energy reserves through heavy exercise, supplemental creatine is thought to be useful for maintaining the optimal levels within muscle cells without overloading the body's capacity for its biosynthesis.  This can potentially help the muscles to prepare more rapidly for withstanding further exercise (i.e. recover). 

Thanks for your very timely & interesting questions,

Jeff Buzby, Ph.D.
Children's Hosp.-Orange County
MadSci Cell Biology Network