Creatine Monohydrate
Summary
A naturally occurring compound stored mostly in skeletal muscle. One of the most studied supplements in sports science, with consistent trial evidence for high-intensity performance and lean-mass gains when combined with resistance training.
Mechanism
Creatine is a naturally occurring compound stored mostly in skeletal muscle, where it is phosphorylated to phosphocreatine. Phosphocreatine donates a phosphate group to regenerate ATP during short, high-intensity efforts, and supplementing raises intramuscular creatine/phosphocreatine stores, speeding that ATP resynthesis.
Reported effects
Ratings are relative to peers in the same category, not absolute claims.
Studied dosing — research context
Trials most commonly use 3-5 g/day as a maintenance dose; many studies include a loading phase of approximately 20 g/day for 5-7 days. Long-term trials have run up to 5 years. These are doses used in research, not guidance.
Research context only. This is not a recommendation.
Safety
The ISSN position stand concludes that short- and long-term use (studied up to 30 g/day for up to 5 years) showed no detrimental effects on health markers in healthy individuals in published trials. The most commonly reported effects are weight gain (partly intracellular water) and occasional gastrointestinal discomfort at high single doses. No consistent evidence of kidney damage in healthy adults has appeared in the trial literature.
Limitations
Most participants in the trial literature are young, healthy men; data in women, adolescents, and clinical populations are thinner. Performance benefits are specific to high-intensity, short-duration work. Cognitive and neuroprotective claims are early-stage and not established.