Real-world creatine supplementation: a large-scale cross-sectional study of use, knowledge, and experiences

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BACKGROUND: Creatine is among the most extensively studied dietary supplements in sports nutrition, yet real-world supplementation patterns, knowledge, and outcomes remain poorly characterized. Prior survey research has focused on competitive athletes and younger male samples, even as the evidence base has expanded to support applications in healthy aging, cognition, and female physiology. Whether use patterns, perceived benefits, and adverse effects among the broader and more diverse population now using creatine align with trial evidence, and whether they differ by gender identity and age, has not been systematically assessed. METHODS: An online cross-sectional survey was distributed to approximately 110,000 users of a supplement tracking application (SuppCo, Inc.) with recorded creatine use, yielding 2,178 analyzable responses from individuals reporting current or past-12-month creatine use (1,077 women and 1,101 men; median age, 55 years). The survey assessed supplementation patterns, goals, creatine knowledge (six-item battery scored via generalized partial credit item response theory [IRT] modeling), side effects, satisfaction, and information needs. Multivariable analyses included logistic regression for perceived benefit, modified Poisson regression for side-effect prevalence, and OLS regression for satisfaction, with Benjamini-Hochberg correction for multiple comparisons. As an exploratory analysis, a mixed graphical model (MGM) characterized conditional associations across measurement domains, and IRT discrimination parameters were combined with network centrality to identify candidate keystone misconceptions. RESULTS: < .001). Women reported higher self-reported side-effect prevalence (PR = 1.48; 95% CI 1.15-1.91) and lower odds of perceived benefit (OR = 0.66; 95% CI 0.55-0.80) than men, with a flatter dose-benefit slope (women × dose OR = 0.65; 95% CI 0.53-0.80). Knowledge of creatine, scored via IRT theta from a five-item battery, was the most consistent positive correlate across all primary outcomes: perceived benefit, satisfaction, the positive experience composite, and above-common dosing. An exploratory IRT-by-network analysis identified kidney damage as the candidate keystone misconception, with the highest IRT discrimination and above-median cross-domain centrality; the network also identified long-term safety beliefs as conditionally associated with intent to continue, consistent with the hypothesis that safety beliefs track behavioral persistence. CONCLUSIONS: In this middle-aged, gender-balanced community sample of creatine users, behavioral loyalty was high yet substantial knowledge gaps, unmet benefit expectations, and self-reported side-effect burdens disproportionately affected women and older adults, who together comprise an increasingly important share of contemporary creatine users. Knowledge appeared as the most consistent positive correlate of supplementation experience, suggesting education may be a tractable lever for improving real-world outcomes; misconceptions about kidney safety and long-term tolerability may warrant particular attention as educational targets. The cognitive expectation gap may reflect a dose-translation issue rather than absence of efficacy. These findings generate hypotheses for prospective evaluation of education, gender-tailored dosing guidance, and expectation-setting interventions in real-world creatine users.