My 14 year-old son wants to take creatine monohydrate because he is now weight lifting. Can this harm him and/or affect his liver or kidneys? Are there any other side effects I would need to know about?

The increased interest of the general public in health, fitness and athletic performance in recent years has resulted in a rather substantial increase in the number of commercially available nutritional supplements including creatine supplementation. Creatine monohydrate has gained much popularity as an ergogenic aid for physical activities and sports that rely on strength and power (for example, weight lifting). Many issues about creatine have been arising recently, with high school and college athletes taking supplements. Some of the specific claims that have been made are that 1) creatine may delay fatigue and 2) increase mean power output and total work during repeated bouts of short duration/high intensity exercises.

I would like to refer you to a research paper that is an excellent reference related to creatine supplementation: Effects of creatine supplementation on body composition, strength and sprint performance. Richard B. Kreider, Maria Ferreira et. al. Medicine and Science in Sports and Exercise (MSSE) Vol. 30 (1) January 1998 pp.73 – 82. [Ask your physician or local medical library to see if they can arrange for you to see the article.]

In regard to your question about creatine monohydrate and its effect on the kidneys: The researchers noticed a small but significant increase in fasting serum creatine levels, which is used as an individual marker of renal stress (stress placed on the kidneys). The researchers believe this increase may have been caused by the intense training of the individuals rather than the creatine supplementations.

In response to your question about creatine monohydrate and its effect on the liver: There appeared to be moderate increases in muscle and liver enzyme efflux, another indicator of intense training and exercise.

These indicators as well as others noted in this research paper warrant that further studies are necessary before any conclusions can be made about the safety of long-term use of creatine monohydrate.

Lastly, I would like to leave you with the following: the American College of Sports Medicine does not recommend or endorse dietary supplements or ergogenic aids. The need and the value of ergogenic aids is really questionable for the average individual who engages in exercise. The individual who is healthy needs a well balanced meal plan that will supply all of the necessary nutrients.

PL