One of the most-replicated ergogenic aids in sports science: cheap, safe, and it earns its place.

Creatine monohydrate is among the most-replicated ergogenic aids in sports science: the 2017 ISSN position stand concludes it reliably raises intramuscular phosphocreatine and improves high-intensity performance and training adaptations, and it remains the reference form against which other creatines are judged ^[1][9]. Meta-analyses put numbers on the strength effect (pooled effect sizes versus placebo of roughly 0.24 for lower-limb and 0.32 for upper-limb strength across 50–60 randomized trials each ^[3][4]), consistent with an earlier 100-study meta-analysis showing small-but-significant gains in high-intensity work and lean mass, largest during loading and repeated upper-body efforts ^[2]. About 5 g/day maintains muscle saturation after any loading phase, and the benefit holds independent of age, sex and training status ^[1][3]. Cognition evidence is genuinely emerging but thinner: a systematic review of six RCTs (281 people) found short-term memory and reasoning may improve, mostly in vegetarians and under stress, with young rested omnivores largely unchanged ^[5], echoing the landmark 5 g/day, six-week vegetarian trial that improved working memory and Raven's matrices (p < 0.0001) ^[6]. One controlled crossover found co-ingested caffeine (5 mg/kg) abolished the performance gain from loading despite a similar phosphocreatine rise, a still-debated interaction ^[8]. Long-term intake up to 30 g/day for five years has been reported safe in healthy people, with no reliable evidence of kidney harm, hair loss or cramping at 3–5 g/day ^[1][7].