Long Term Creatine Use

Title: Effects of Long-term Creatine Supplementation on Liver and Kidney Functions in American College Football Players.

Researchers: Mayhew DL, Mayhew JL, Ware JS

Institution: Exercise Science Program at Truman State University, Kirksville, MO 63501 and the Athletic Department at Truman State University, Kirksville, MO.

Summary: The purpose of this study was to determine the effect of long-term Cr supplementation on blood parameters reflecting liver and kidney function.
Methods: Twenty-three members of an NCAA Division II American football team (ages = 19-24 years) with at least 2 years of strength training experience were divided into a Cr monohydrate group (CrM, n = 10) in which they voluntarily and spontaneously ingested creatine, and a control group (n = 13) in which they took no supplements. Individuals in the CrM group averaged regular daily consumption of 5 to 20g for 0.25 to 5.6 years. Venous blood analysis for serum albumin, alkaline phosphatase, alanine aminotransferase, aspartate aminotransferase, bilirubin, urea, and creatinine produced no significant differences between groups.

Results: Creatinine clearance was estimated from serum creatinine and was not significantly different between groups. Within the CrM group, correlations between all blood parameters and either daily dosage or duration of supplementation were nonsignificant.

Conclusion: Oral supplementation with CrM has no long-term detrimental effects on kidney or liver functions in highly trained college athletes in the absence of other nutritional supplements.

Discussion: Questions about creatine's safety are probably the most frequently brought up by people who don't like (and usually don't understand) supplements. This study by Mayhew and colleagues is a welcome addition to the already growing body of creatine safety research. (1,2,3,4,5,6,7)

Most questions revolve around the effects of creatine supplementation on the liver and kidney. These are the two organs are involved in "processing" creatine once it is ingested. The Liver breaks it down and the kidneys excrete it. From this study, and others before it, we see that long term supplementation with creatine in doses usually taken by bodybuilders (5-20 grams) for extended periods of time do not lead to dysfunction of either organ, nor does it cause abnormalities in the indicators of liver and kidney function.

Considering that fact that creatine supplementation has been shown to enhance anaerobic exercise performance by increasing power output (8), muscular strength and work (9,10,11), and muscle fiber size (12), and to top it off, completely safe even with long term supplementation, its no wonder this is one of my first tier recommendation for effective and safe supplements for putting on muscle size.

Reference: http://www.hypertrophy-specific.com/HSreport/iss06/