Does creatine supplementation increase muscle creatine concentrations, body mass, total body water, and effect fluid distribution?
From: Journal of Athletic Training
- Powers, M.E., Arnold, B.L., Weltman, A.L., Perrin, D.H., Mistry, D., Kahler, D.M., Kraemer, W., Volek, J., 2003. Creatine Supplementation Increases Total Body Water Without Altering Fluid Distribution. J Athl Train 38, 44–50.
- 16 men (average age 22.8 years, ave. height 179.8cm, ave. body mass 84.8kg) and 16 women (ave. age 21.8 years, ave. height 163.4cm, ave. body mass 63.6kg).
- After an overnight fast, urinary creatine (Cr) and creatinine concentrations, muscle creatine concentration, body mass, total body water, extracellular water, and intracellular water were measured. Subjects were then randomly assigned to either a creatine or a placebo group.
- The creatine group ingested 25 g/d of Cr for 7 days (loading phase) and 5 g/d for the remaining 21 days (maintenance phase), whereas the placebo group ingested a sucrose placebo using the same protocol.
- The Cr group had significantly greater urinary Cr concentrations on days 7 and 28 as compared with pre-supplementation, whereas no changes were observed in the placebo group.
- Cr group had a greater Cr concentration on days 7 and 28 as compared with pre-supplementation. No changes were observed in the placebo group.
- The Cr group’s body mass on day 7 was 0.75 kg greater than at pre-supplementation; however, this change was not significant. The placebo group did not experience any significant changes in body mass.
- Although no difference existed between the groups before supplementation, the Cr group had a significantly greater total body water volume on days 7 and 28 than did the placebo group.
- Cr supplementation protocol was effective for increasing muscle Cr concentrations, body mass, and total body water; however, fluid distribution was not changed.
- Yes (without confidence). When intracellular water was expressed relative to the total body water, no significant changes were noted.
- Studies have reported increases in body mass after only a loading phase of creatine supplementation (20–25 g/d for 5–7 days). Thus, it is likely that the gains are due more to greater water retention during supplementation than to lean-tissue accretion.