Effects of Caffeine Dose and Administration Method on Time-Trial Performance: A Systematic Review and Network Meta-analysis

Background: Caffeine is a proven ergogenic aid for endurance performance, but the optimal intake strategy (i,e., administration method and dosage) remainsunclear. This systematic review and network meta-analysis aimed to systematically evaluate and compare the effectiveness of different caffeine administration methods and dosages on time-trial performance. Methods: A systematic search of PubMed, Embase, Web of Science, Scopus, and SPORTDiscus was conducted up to July2025. Eligible studies were screened and assessed for methodological quality by two independent reviewers. Pairwise and network meta-analyses were conducted to examine the effects of caffeine administration methods (e.g., capsules/tablets, gum, mouth rinse) and dosages (low: ≤ 3 mg/kg; moderate: 4-6 mg/kg) on time-trial performance. Results: Forty-eight studies with 612 participants were included. Network meta-analysis ranked low-dose capsules as most effective for reducing completion time (standardized mean differences [SMD] = -0.34; 95% confidence interval [CI] -0.62, -0.06), followed by moderate-dose capsules (SMD = -0.31; 95% CI: -0.45, -0.17) and moderate-dose gum (SMD = -0.30; 95% CI: -0.57, -0.02). Low-dose capsules also showed the greatest improvement in mean power output (SMD = 0.38; 95% CI: 0.09, 0.67), with moderate-dose capsules second (SMD = 0.30; 95% CI: 0.12, 0.48). Conclusion: This systematic review and network meta-analysis indicated that low-dose caffeine capsules (≈3 mg/kg) represent the optimal intake strategy for improving time-trial performance, with moderate-dose capsules and moderate-dose gum as effective alternatives.