1. Department of Pathology, Immunology and Laboratory Medicine, University of Florida College of Medicine
2. Department of Pharmacy Practice, University of Florida College of Pharmacy, Gainesville, FL, USA

Four subjects were administered a loading dose of creatine monohydrate (5 g, 4 times daily for 5 days), followed by maintenance dosing (5 g, 1 time daily for 5 days). All discrete urine specimens were collected during the course of the study that included the collection of urine specimens 2 days prior to and following creatine administration. A total of 307 discrete urine specimens were obtained during the course of the study and the urinary creatinine, pH, and specific gravity values were determined. The data including mean (± SD) are summarized below:

Subject	Time of Urine Collection Relative to Creatine Administration	N	Creatinine (mg/dL)	S.G.	pH
1	Before	16	64.0 ± 42.6	1.010 ± 0.006	5.8 ± 0.6
	During/After	71	78.9 ± 51.5	1.012 ± 0.007	6.2 ± 0.6
2	Before	10	327.8 ± 64.7	1.035 ± 0.002	5.7 ± 0.3
	During/After	60	219.0 ± 46.7	1.027 ± 0.003	6.1 ± 0.4
3	Before	8	182.4 ± 45.3	1.024 ± 0.003	6.3 ± 0.4
	During/After	70	104.7 ± 62.2	1.017 ± 0.007	6.3 ± 0.6
4	Before	10	131.3 ± 26.8	1.016 ± 0.004	6.1 ± 0.2
	During/After	62	123.2 ± 65.6	1.012 ± 0.005	5.8 ± 0.3

The majority of discrete creatinine and specific gravity values and all discrete pH values were within normal limits. Regression analysis of the discrete specific gravity and creatinine concentration values revealed the following range of correlation coefficient (r²) values: 0.6063 - 0.8274. Individual plots of all discrete urine specimen values (creatinine, specific gravity, pH) versus 'time' did not reveal any apparent effect of creatine administration on these measurements. These data suggest that oral creatine supplementation, given at recommended doses, does not appear to influence the discrete urinary creatinine, specific gravity, or pH values.