Caffeine and taurine: a systematic review and network meta-analysis of their individual and combined effects on physical capacity, cognitive function, and physiological markers.

backgroundCaffeine (CAF) and taurine (TAU) have each demonstrated ergogenic effects across physical and cognitive domains. Often co-formulated in commercial energy drinks, they are widely regarded as the two principal bioactive compounds. However, findings regarding their combined efficacy remain inconclusive. This systematic review and Bayesian network meta-analysis aimed to quantify the individual and combined effects of CAF and TAU on physical capacity, cognitive function, and physiological responses, with a focus on identifying potential synergistic or antagonistic interactions.

methodsCochrane Library, PubMed, SciELO, SportsDiscus-EBSCO and Web of Science were searched through 25 July 2025. The pooled effect of each outcome was summarized using SMD (Hedge's g) by Bayesian arm-based multilevel network meta-analysis, and SUCRA ranking was applied to estimate the relative treatment effect.

resultsTwelve studies were included (8 on physical capacity, 7 on blood lactate (B[la]), and 6 each on cognitive function, heart rate (HR), and rating of perceived exertion (RPE)). Posterior estimates indicated that CAF+TAU was associated with a credible positive effect on anaerobic capacity (g = 0.46, 95% CrI [0.19, 0.71]) and reaction time (g = 0.75, 95% CrI [0.29, 1.18]) compared to CAF or TAU alone. CAF showed the greatest posterior reduction in RPE (g = -0.64, 95% CrI [-1.20, -0.10]), while its posterior mean estimate suggested a potential increase in B[la] (g = 0.24, 95% CrI [-0.48, 0.96]). In contrast, TAU showed a possible tendency toward reducing B[la] (g = -0.30, 95% CrI [-1.01, 0.42]). No credible differences in HR were observed across conditions. Effects on aerobic performance and physiological measures were variable and appeared to be context-dependent. SUCRA rankings consistently favored CAF+TAU across most outcome domains.

conclusionsCAF+TAU co-supplementation provides a balanced ergogenic effect, combining the central stimulation of CAF with the neuromodulatory and metabolic support of TAU, particularly beneficial for high-intensity, reaction-based tasks. Its effects on endurance and physiological indices vary by condition, highlighting the need for personalized application.