Long-term creatine supplementation does not significantly affect clinical markers of health in athletes

Ingesting creatine with carbohydrate or carbohydrate and protein have been reported to more consistently promote greater creatine retention.

“Ingesting creatine with carbohydrate or carbohydrate and protein have been reported to more consistently promote greater creatine retention”

No evidence has suggested that muscle creatine levels fall below baseline after cessation of creatine supplementation; therefore, the potential for long-term suppression of endogenous creatine synthesis does not appear to occur.

“No evidence has suggested that muscle creatine levels fall below baseline after cessation of creatine supplementation; therefore, the potential for long-term suppression of endogenous creatine synthesis does not appear to occur”

The only consistently reported side effect from creatine supplementation that has been described in the literature has been weight gain.

“The only consistently reported side effect from creatine supplementation that has been described in the literature has been weight gain [5, 22, 46, 78, 91, 92, 112].”

These studies and others have led researchers to conclude that there is no compelling evidence that creatine supplementation negatively affects renal function in healthy or clinical populations.

“While some have suggested that individuals with pre-existing renal disease consult with their physician prior to creatine supplementation in an abundance of caution, these studies and others have led researchers to conclude that there is no compelling evidence that creatine supplementation negatively affects renal function in healthy or clinical populations [5, 6, 22, 53, 259, 266, 267].”

Performance-related studies in adolescents, younger individuals, and older populations have consistently reported ergogenic benefits with no clinically significant side effects.

“Performance-related studies in adolescents, younger individuals, and older populations have consistently reported ergogenic benefits with no clinically significant side effects [5, 6, 22, 23, 53, 113, 129, 244, 245, 268].”

Multiple shorter and long-term safety studies have reported no apparent side effects from creatine supplementation and/or that creatine monohydrate may lessen the incidence of injury during training.

“Although concerns have been raised about the safety and possible side effects of creatine supplementation [189, 190], multiple shorter [191–193] and long-term safety studies have reported no apparent side effects [188, 194, 195] and/or that creatine monohydrate may lessen the incidence of injury during training [196–199].”

The only clinically significant side effect occasionally reported from creatine monohydrate supplementation has been the potential for weight gain.

“The only clinically significant side effect occasionally reported from creatine monohydrate supplementation has been the potential for weight gain [181, 182, 187, 188].”

In adults, a growing number of published randomized controlled trials support the safety of creatine supplementation.

“In adults, a growing number of published randomized controlled trials are available that support the safety of creatine supplementation.”

Larger athletes engaged in intense training may need to consume 5-10 g/day of creatine to maintain optimal or capacity whole body creatine stores.

“larger athletes engaged in intense training may need to consume 5–10 g/day of creatine to maintain optimal or capacity whole body creatine stores”

Kreider et al. reported that creatine supplementation (5-10 g/day for 21 months) had no significant effects on creatinine or creatinine clearance in American football players.

“Kreider et al. [22] reported that creatine supplementation (5–10 g/day for 21 months) had no significant effects on creatinine or creatinine clearance in American football players.”

Creatine supplementation does not increase the incidence of gastrointestinal upset.

“or gastrointestinal upset [22, 111, 112, 241].”

Creatine supplementation does not increase the incidence of musculoskeletal injuries.

“showing that creatine supplementation does not increase the incidence of musculoskeletal injuries [22, 111, 112, 241]”

The literature has not provided support that creatine promotes renal dysfunction.

“Nor has the literature provided any support that creatine promotes renal dysfunction [22, 51, 85, 114, 156, 172, 243–248]”

The literature has not provided support that creatine has long-term detrimental effects.

“or has long-term detrimental effects [22, 23, 53, 155, 172].”

Creatine supplementation, with or without glycerol, helps athletes hyper-hydrate and thereby enhance tolerance to exercise in the heat.

“creatine supplementation (with or without glycerol) has been reported to help athletes hyper-hydrate and thereby enhance tolerance to exercise in the heat [28, 37, 131–145].”

The systematic review included 21 studies.

“Twenty-one studies were included in the systematic review”

In adult athletic populations, creatine supplementation consistently demonstrates improvements in muscular strength, power output, and lean body mass, alongside a well-established safety profile across both short- and long-term use.

“In these populations, creatine supplementation consistently demonstrates improvements in muscular strength, power output, and lean body mass, alongside a well-established safety profile across both short- and long-term use [3-5].”

Creatine has a strong safety profile and minimal risk for adverse events or any negative influence on markers of clinical health and safety.

“There is also strong support for creatine regarding its safety profile and minimal risk for adverse events or any negative influence on markers of clinical health and safety.”

Adult studies of creatine supplementation range from a few days to as long as 5 years without adverse changes in markers of clinical health.

“These studies have been conducted in both athletic and general populations and range from as short as a few days to as long as 5 years without any adverse changes in markers of clinical health (12, 13).”

The only clinically significant side effect of CM reported in literature has been weight gain.

“The only clinically significant side effect reported in literature has been weight gain, which is an attribute desired by many athletes who desire to increase muscle mass as well as clinical populations concerned about muscle wasting (Bender et al. 2008; Dalbo et al. 2008; Kreider et al. 2003a; Schilling et al. 2001).”

Other studies found that creatine supplementation did not increase the incidence of musculoskeletal injuries, dehydration, muscle cramping, gastrointestinal issues, renal dysfunction, or long-term detrimental effects.

“Other studies directly assessed the merit of anecdotal reports of side effects and found that creatine supplementation did not increase the incidence of musculoskeletal injuries [84–87], dehydration [85,86,91–96], muscle cramping [80,85,86,92,97], gastrointestinal issues [84–87], promote renal dysfunction [87,89,98–107], or have long-term detrimental effects [50,87,106,108,109].”

Present findings are consistent with other safety studies on creatine supplementation and the long-term study conducted in Parkinson's patients.

“They are also consistent with other safety studies on creatine supplementation [50,80,84–87,89,91–109] and the long-term study conducted in Parkinson’s patients [74].”

Present findings are similar to results reported in the authors' long-term creatine safety study on American football players, where up to 21 months of creatine supplementation (5-10 g/d) in division I American football players did not significantly affect markers of health or renal function.

“Present findings are similar to results reported in our long-term creatine safety study on American football players [86,87], where we showed that up to 21 months of creatine supplementation (5–10 g/d) in division I American football players did not significantly affect markers of health or renal function [87]”