Fast-Acting Caffeine Strategy: A Systematic Review and Meta-Analysis of the Ergogenic Effects of Caffeine Chewing Gum on Physical Performance

Background Caffeine gum is a fast-acting delivery method that rapidly elevates circulating caffeine levels and may improve physical performance. Given the recent growth in research, an updated systematic review and meta-analysis is warranted. Objectives To evaluate the acute effects of caffeine gum on physical performance compared with placebo, and investigate potential moderators including (1) training status, (2) exercise type, (3) chewing duration, (4) caffeine habituation (i.e., habitual intake), (5) caffeine dosage, and (6) timing of administration relative to exercise. Methods The review followed the Cochrane Handbook for Systematic Reviews of Interventions and PRISMA guidelines. PubMed, Web of Science, Scopus and SPORTDiscus were searched up to March 2026. Three-level meta-analyses were synthesized for outcomes. Sensitivity analyses addressed assumptions within-subject correlations, outliers, and influential cases. Risk of bias was assessed using standardized tools. Results Thirty-one studies were assessed for full-text eligibility, of which 25 (n = 390 participants) met the inclusion criteria and were included in the meta-analysis. Caffeine gum produced a trivial but significant improvement in physical performance (SMD = 0.195, 95% CI [0.115, 0.275], p = 0.001; GRADE: low) with very low heterogeneity (I 2 = 4%). Three-level variance decomposition indicated that most variability was between studies (64.6%), with no within-study variance. Aerobic endurance showed a small significant effect (p = 0.002), whereas trivial but significant effects were observed for anaerobic performance (p = 0.005) and vertical jump outcomes (p = 0.008). Benefits were evident with a 10-min chewing duration (p = 0.001) for trained individuals (p = 0.018), and among individuals with low (p = 0.003) or moderate (p = 0.013) habitual caffeine intake, but not significant for recreationally active participants (p = 0.676), muscular strength/endurance outcomes (p = 0.372), 5-min chewing duration (p = 0.091), or high habitual caffeine users (p = 0.290). Meta-regression showed a significant dose–response relationship (p = 0.031), whereas the timing of caffeine administration relative to exercise had no effect (p = 0.683). Sensitivity analyses confirmed the robustness of findings across correlation assumptions and leave‑one‑out procedures. Most studies were judged as having some concerns or a high risk of bias. No evidence of publication bias was detected where assessable, although some subgroup analyses could not be formally evaluated because of the limited number of studies. The certainty of the evidence ranged from low to very low. Conclusion Caffeine gum produced statistically significant but trivial improvements in physical performance, suggesting limited practical significance. However, even these small improvements may provide a competitive advantage in certain sporting situations. Registration The protocol was prospectively registered in the PROSPERO database (CRD420251086458).