Acute caffeine intervention and cognitive performance in populations aged 20 years and younger: a systematic review...

This systematic review and meta-analysis aimed to evaluate the acute effects of caffeine supplementation on cognitive performance in healthy populations aged 20 years and younger, and to explore potential moderators including dose, cognitive domain, population type, and outcome measure.

Four databases (Web of Science, PubMed, MEDLINE, and Cochrane Library) were searched from inception to March 2026. Randomized controlled trials and randomized crossover trials assessing the effects of acute oral caffeine versus placebo on cognitive outcomes in individuals aged ≤20 years were included. A two-level meta-analytic model was used to calculate pooled standardized mean differences (SMD). Subgroup analyses and meta-regression were performed to explore potential methodological moderators influencing the overall effect.

Fourteen studies comprising 250 participants and 37 effect sizes were included. Caffeine demonstrated a small positive effect on cognitive task performance compared with placebo (SMD = 0.41, 95% CI 0.28-0.55; p < 0.01), with low heterogeneity (I² = 10%). Meta-regression showed no significant moderating influences of age, acute supplementation dose, habitual daily intake, and acute-to-habitual dose ratio on caffeine-induced cognitive improvements. However, limited statistical power may restrict the interpretability of this result. Subgroup analyses showed that cognitive domain, outcome measure type, participant population, administration route, and sex did not significantly moderate caffeine's cognitive effects. Notably, however, when comparing outcome measure types, the enhancement magnitude of caffeine on reaction time was greater than that on accuracy, with this difference approaching statistical significance (p = 0.08). Sensitivity analyses confirmed the robustness of the findings, and no publication bias was detected.

Among individuals aged 20 and younger, acute caffeine ingestion produces a small yet statistically significant beneficial effect on cognitive performance. Specifically, moderate improvements were observed in psychomotor speed and attention, alongside smaller gains in executive function. No significant moderators influencing this ergogenic effect were identified in the present meta-analysis. Importantly, the conclusion that habitual caffeine intake exerts no moderating impact is derived from only seven studies and may be limited by insufficient statistical power. These findings offer tentative support for the judicious use of caffeine to boost cognition among young athletes and healthy adolescents, yet caution is warranted given the small number of small-sample studies.

This systematic review has been registered in PROSPERO (International Prospective Register of Systematic Reviews) under registration number CRD420261342996.