Creatine Side Effects. Fact or Fiction?

February 4, 2002


1- Featured Article:
Creatine’s Side Effects. Fact or Fiction?
An interview with Professor Jacques R. Poortmans

Welcome to the February 2002 issue of the Creatine Newsletter. In this issue of the Creatine Newsletter I interview Dr. Jacques R. Poortmans, one of the world’s foremost creatine authorities, about possible creatine side effects. Professor Poortmans has authored several highly cited articles on the topic.

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This Month’s Featured Article:

Creatine’s Side Effects. Fact or Fiction?

An interview with Professor Jacques R. Poortmans

Dr. Jacques Poortmans of the Free University of Brussels in Belgium is one of the world’s foremost creatine experts. His articles examining the consequences of creatine supplementation have appeared in many of the premier sport medicine journals. For this issue of the Creatine Newsletter I was fortunate to be able to interview Dr. Poortmans. I’m sure you’ll find it as enlightening as I did.

NSN: A common concern is that creatine supplementation places undue stress on renal function. Is there any truth to this?

JRP: No, as long as renal functions are normal before any creatine supplementation. We, and others, have given published evidences that in healthy individuals short-term, medium-term and long-term oral creatine monohydrate supplements are safe for the kidney. Of course, one has to be certain that the product is PURE (by analysis) since there are, apparently, many commercial products which do not satisfy the quality imposed by the FDA.

NSN: It is known that creatine absorption by our muscles decreases dramatically after a week of loading and that afterwards most of the ingested creatine is cleared from the body by the kidneys. Given this information, is there any harm in extending the loading phase past one week?

JRP: No, if one respects the loading doses: about 20 grams per day for 5 days and thereafter a 2-3 gram doses per day. One has to know that about 60% of the ingested doses are not taken up by the muscles and are cleared into the urine. What a waste of money!

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NSN: What effect does creatine monohydrate have on liver function?

JRP: None. Again, we and others did not observe any impairment of liver tests after oral creatine supplements in healthy subjects (men and women).

NSN: Who should avoid creatine use? Diabetics who are predisposed to renal complications, for example?

JRP: Certainly those patients as well as anyone suffering from ANY kidney impairment. Heavy creatine supplements still remain an extra load on the renal filtration process.

NSN: Is taking creatine with protein a mistake?

JRP: Recent investigations by us and another research team did not observe a difference between creatine alone or creatine + protein as far as muscle composition is concerned. What seems important is to provide enough daily protein intake (about 1.2-1.3 g/kg body weight, no more) to sustain protein synthesis.

NSN: I often get asked about secondary sexual side-effects associated with creatine use. As far as you know is there any basis for this concern?

JRP: There is no reason to believe that there is a relationship between creatine and sexual behavior (or capability). But, as usual, it might be of some help for those who sentimentally believe in anything. However, as said before, be careful with the purity of the product. We know that some commercials add anabolic steroids to creatine. This conduct cannot be tolerated. Excess anabolic steroid substances can have negative effects on sex and general health care.

Also visit our creatine side effects and benefits pages.

Recently, the French Agency for Medical Security of Food (AFSSA) shocked the athletic world with claims that creatine use causes cancer. This interview of Dr. Markus Wyss, renowned creatine expert, analyzes the validity of the allegations made by the AFSSA.

Scientific Reference

Poortmans J.R. and Francaux M. (September 2000) Adverse Effects of Creatine. Fact of Fiction? Sports Medicine Volume 30:3: pages 155-170.

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