This month, Dietary Supplement University is "diggingin" to one of the most popular dietary supplements to date. And for goodreason -- there's actually research to support it: Creatine monohydrate. First,some background. Creatineis a naturally occurring amino acid-like compound found primarily in themuscle. About half the daily creatine needs come from the diet and the rest issynthesized from the amino acids arginine, glycine and methionine.

Function: Peopletake creatine supplements to improve exercise performance. It has been shown tobe most effective in short duration, high intensity activities (weight lifting,sprinting, football, etc). During the first 0-15 seconds of explosive exercise,the body relies on what's called "rephosphorylation" of adenosinediphosphate (ADP) to adenosine triphosphate (ATP) for energy. This process --ADP to ATP -- is dependent on the availability of PCr (phosphocreatine). As PCrlevels become depleted, the body can't continue to resynthesize ATP whichaffects workout duration and intensity. Theoretically, supplemental creatinecan boost PCr levels to improve this "system" of replenishing ATP andperformance can improve.

While we can get creatine from the diet -- foodslike herring,salmon, beef, pork and tuna are particularly high -- getting the dose showneffective in research would be difficult through foods only.

Effectivenessand safety: Creatine is one of the most extensively studied andeffective supplements to date. Oral doses of creatine may enhance musclefunction during high-intensity exercise, but it may not be able to improveendurance or performance in well-trained athletes. Creatine may also causemuscle hypertrophy, likely due to increased water retention by muscle cells,although some data suggest there may be gains in muscle fiber diameter as well.

Research suggests creatine supplements can be used safelyfor up one to five years when used appropriately. And although endogenousproduction of creatine stops during supplementation, after supplementationstops, muscle levels return to baseline within four weeks.

Supplementationguidelines: Typical administration of creatine involves accumulating(a.k.a. "loading") supplemental creatine monohydrate in the systemfor five to seven days at 0.3 g/kg/day and then a "maintenance" doseof 3-5 g/day to maintain elevated stores. Although one study found thatsubjects who ingested 3 g/day daily for 28 days had similar muscle creatinestores at the end of 28 days without the loading protocol outlined above.

Side effects:Althoughanecdotal evidence suggests muscle cramping, dehydration and gastrointestinalsymptoms such as pain, nausea and diarrhea may be issues, the only clinicalside effect that has been duplicated in the literature is weight gain.

There is certainly no shortage of controversies surroundingcreatine supplementation -- what's the best form to take, should athletes cyclecreatine, and what's the best time to take it. For now, we've only got enoughroom to cover the basics. Check out Dietary Supplement U for answers to thecontroversial questions.

Dr. Chris Mohr created Dietary Supplement University, theone stop resource for many of the most popular supplements your clients areasking about and using. Every vitamin, mineral, and many popular supplementsare reviewed in this popular resource all at your fingertips. Visit www.DietarySupplementU.comto let Dr. Mohr do all the dietary supplement 'dirty work' for you.