Effects of creatine supplementation on exercise performance, physiological outcomes, and body composition in females engaged in exercise or training: a systematic review and multilevel meta-analysis.

BACKGROUND: Female-specific creatine trials span different sports, training states and outcome types. The preceding systematic review included 27 studies and provided a narrative synthesis of performance outcomes; the average magnitude of effects across correlated outcomes remained unknown. OBJECTIVE: To estimate overall and domain-specific effects of creatine supplementation on exercise and sport performance, physiological outcomes and body composition in females engaged in exercise, sport or structured training. METHODS: PubMed, Scopus, Web of Science, SPORTDiscus and CINAHL were searched for experimental studies published from 1 January 1996 to 5 March 2026. Two reviewers independently screened records, extracted data and appraised risk of bias. Female-specific creatine-vs.-control contrasts were synthesized with multilevel random-effects models and CR2 small-sample robust inference. Sensitivity analyses addressed graph-digitized and reconstructed percentage-change data and plausible within-study sampling correlations. GRADE was applied to the overall estimate and each quantitative domain. The review was retrospectively registered on OSF (https://doi.org/10.17605/OSF.IO/U8V7A). RESULTS: The search identified 13,244 records; 160 reports were assessed in full text, and 34 studies with 692 female or female-eligible participants entered the systematic review. Twenty-one studies contributed 170 model-compatible effects from 424 analyzable participants. The overall model yielded a small positive estimate (Hedges g = 0.23, CR2 robust 95% CI 0.09 to 0.37). The performance model yielded g = 0.30 (95% CI 0.06 to 0.54), and the body-composition model yielded g = 0.24 (95% CI 0.06 to 0.43). The body-composition model combined outcomes without a uniform favorable direction. The physiological estimate was uncertain (g = 0.10, 95% CI -0.17 to 0.38). Risk-of-bias concerns and variation in protocols and outcomes reduced certainty, which was low for performance and body composition and very low for the overall and physiological evidence. CONCLUSION: Available female-specific evidence suggests possible small effects on selected strength, power, high-intensity performance and lean-mass-related measures. Substantial heterogeneity, methodological limitations and low or very-low certainty prevent firm sport-specific or outcome-specific conclusions. SYSTEMATIC REVIEW REGISTRATION: https://doi.org/10.17605/OSF.IO/U8V7A, identifier: OSF.IO/U8V7A.