Potential side effects of oral creatine supplementation: a critical review.
Level 5 - mechanism / opinion, no new human data
Narrative review of human and animal studies on creatine metabolism and adverse effects.
PubMed 9884794 · doi:10.1097/00042752-199810000-00007
What was done
The authors searched Medline and conference abstracts for human and animal studies on the adverse effects and organ-specific metabolism of oral creatine supplementation, grouping findings by organ system.
What was found
The abstract reports no numerical data. Creatine supplementation causes weight gain due to water retention, which may impair performance in running and swimming. Short-term use (fewer than 28 days) at recommended doses demonstrated no significant adverse effects, but potential effects on the brain, cardiac muscle, testes, renal system, and hepatic system remain largely unstudied.
Why it matters
This review clarifies that early safety assumptions regarding creatine were based on very short trials in small cohorts, emphasizing the necessity of large randomized controlled trials to assess multi-organ and long-term effects.
Limits
The abstract does not provide the total number of studies included or quantitative effect sizes. The reviewed literature was limited by small sample sizes, absent sample size calculations, short observation periods (<28 days), and a lack of data on major organ systems.
Cited by
- supports Creatine supplementation causes individuals to gain approximately three pounds of body weight in water weight.