Background: This systematic review and exploratory meta-analysis evaluated the effects of combined music and caffeine on psychophysiological responses during exercise. Methods: PubMed, Embase, Web of Science, and the Cochrane Library were searched from database inception to 10 June 2026. Randomized crossover studies comparing caffeine plus music with placebo plus no music, caffeine alone, or music alone were eligible. Outcomes included rating of perceived exertion (RPE), Physical Activity Enjoyment Scale (PACES), Feeling Scale (FS), and heart rate (HR). Findings were synthesized descriptively by outcome and comparator, considering study-specific effect estimates, confidence intervals, and experimental conditions. Random-effects meta-analyses were retained as secondary exploratory summaries. Because fewer than 10 independent studies were available, meta-regression and formal assessment of small-study effects were not undertaken. Results: Five crossover studies involving 88 participants were included. Study-specific RPE estimates varied from large reductions to estimates close to the null or in the opposite direction. PACES point estimates favoured the combined intervention, but their magnitudes differed substantially in comparisons with placebo plus no music and caffeine alone. Feeling Scale and heart-rate findings also varied across studies. All four primary meta-analyses showed I² values exceeding 90%, and the certainty of evidence was very low for all primary outcomes. Conclusions: The available evidence comprises five small crossover studies conducted in different populations and experimental settings. Study-specific findings suggest possible improvements in exercise enjoyment, while perceived exertion, affective valence, and heart-rate responses vary across studies. Neither the descriptive findings nor the secondary exploratory pooled estimates establish a stable, broadly applicable magnitude of intervention benefit. Given the very low certainty of evidence, no firm recommendations can be made regarding the use of caffeine combined with music across exercise populations and settings. Further adequately powered studies using clearly specified interventions and comparable outcome assessments are needed to determine which responses are reproducible and practically meaningful.

Background: Caffeine–taurine combinations are widely used in commercial sports products. Whether this combination improves exercise performance is still unclear. This study aimed to estimate the effect of caffeine–taurine co-supplementation versus placebo on exercise performance. Methods: Randomized controlled trials comparing caffeine plus taurine versus placebo were searched in PubMed, Embase, Web of Science, Cochrane Library, and related databases up to June 1, 2026. Outcomes included heart rate (HR), reaction time (RT), time to exhaustion (TTE), rating of perceived exertion (RPE), and peak/maximal anaerobic power (PP). A random-effects model was applied. Risk of bias was assessed with RoB 2.0. Results: A total of 11 randomized controlled trials involving 234 participants were included in the meta-analysis. Compared with placebo, caffeine–taurine co-supplementation was associated with improvements in time to exhaustion (SMD = 0.54, 95% CI: 0.03 to 1.05) and PP (SMD = 0.55, 95% CI: 0.21 to 0.89); an expanded secondary product-level analysis that additionally included one commercial multi-ingredient energy drink yielded a smaller estimate (SMD = 0.48, 95% CI: 0.19 to 0.78) that cannot be attributed specifically to caffeine and taurine. The pooled estimate for reaction time favored supplementation (SMD = −1.49, 95% CI: −2.78 to −0.20), but very high heterogeneity and a prediction interval crossing the null indicated that the effect was not consistent across settings, whereas no meaningful effect was observed for heart rate (WMD = −0.11, 95% CI: −5.76 to 5.53). Rating of perceived exertion was significantly reduced (SMD = −0.44, 95% CI: −0.83 to −0.04). Conclusions: Caffeine–taurine-only formulations were associated with possible benefits for selected performance outcomes, including PP. However, the evidence was derived from few, generally small studies and did not establish the independent contribution of caffeine, taurine, or their interaction. Results from commercial multi-ingredient products should be interpreted at the product level rather than as evidence of an isolated caffeine–taurine effect.