This is one of the mechanisms by which creatine is thought to work, as it increases a cell's fluid volume, which may then promote cell growth.

Short-term adaptations include increased cycling power; total work performed on the bench press and jump squat; and improved sport performance in sprinting, swimming, and soccer (Volek et al. 1997; Mero et al. 2004; Wiroth et al. 2001; Tarnopolsky and MacLennan 2000; Skare, Skadberg, and Wisnes 2001; Mujika et al. 2000; Ostojic 2004; Theodorou et al. 1999; Preen et al. 2001). Long-term adaptations when creatine monohydrate supplementation is combined with training include increased muscle creatine and PCr [phosphocreatine] content, lean body mass, strength, sprint performance, power, rate of force development, and muscle diameter (Kreider et al. 1998; Volek et al. 1999; Vandenberghe et al. 1997). In long-term studies, subjects taking creatine monohydrate typically gain about twice as much body mass, fat-free mass, or both (i.e., an extra 2 to 4 pounds of muscle mass during 4 to 12 weeks of training) as subjects taking a placebo (Stone et al. 1999; Noonan et al. 1998; Kirksey et al. 1999; Jones, Atter, and Georg 1999). The only clinically significant side effect reported in the research literature is weight gain (Kreider, Leutholtz, and Greenwood 2004; Kreider et al. 2003); however, many anecdotal claims of side effects, including dehydration, cramping, kidney and liver damage, musculoskeletal injury, gastrointestinal distress, and anterior (leg) compartment syndrome, still appear in the media and popular literature. While athletes who are taking creatine monohydrate may experience these symptoms, the scientific literature suggests that these athletes have no greater, and a possibly lower, risk of these symptoms than those not supplementing with creatine monohydrate (Greenwood et al. 2003; Kreider et al. 2003). The position stand also included the statement, “The tremendous numbers of investigations conducted with positive results from creatine monohydrate supplementation lead us to conclude that it is the most effective nutritional supplement available today for increasing high-intensity exercise capacity and building lean mass.”