Caffeine Plus Taurine Beats Either Alone for Anaerobic Power and Reaction Speed

Caffeine and taurine are the two most prevalent bioactive compounds in commercial energy drinks and among the most studied ergogenic aids in sports nutrition. Despite their widespread co-formulation, rigorous evidence comparing their individual versus combined effects has been lacking. This systematic review and Bayesian network meta-analysis, published in the Journal of the International Society of Sports Nutrition, represents the first attempt to directly quantify synergistic or antagonistic interactions between CAF and TAU across physical performance, cognitive function, and key physiological markers using network meta-analytic methods.

Researchers searched five major databases (Cochrane Library, PubMed, SciELO, SportsDiscus-EBSCO, and Web of Science) through July 2025. Twelve studies met strict inclusion criteria: human subjects, peer-reviewed full-text, at least one CAF+TAU condition, single-blind randomized controlled design minimum, and outcomes focused on exercise performance and physiological responses. Studies co-administering additional supplements (amino acids, glucose, carbohydrates) alongside CAF and TAU were excluded to isolate the specific compound effects. The final sample comprised 8 studies on physical capacity, 7 on blood lactate, and 6 each on cognitive function, heart rate, and rating of perceived exertion (RPE). Effect sizes were computed as Hedge's g (bias-corrected for small samples) and synthesized via Bayesian arm-based multilevel network meta-analysis, with SUCRA rankings used to estimate relative treatment probability.

For anaerobic capacity, CAF+TAU demonstrated a credible positive effect over either compound alone (g = 0.46, 95% CrI [0.19, 0.71]), with the credible interval fully excluding zero — one of the stronger findings in the analysis. Reaction time showed an even larger benefit for the combination (g = 0.75, 95% CrI [0.29, 1.18]), suggesting meaningful cognitive-motor advantages. Caffeine alone produced the greatest reduction in RPE (g = -0.64, 95% CrI [-1.20, -0.10]), consistent with its known adenosine-receptor antagonism reducing perceived fatigue. Taurine showed a non-credible but directionally interesting tendency to reduce blood lactate (g = -0.30, 95% CrI [-1.01, 0.42]), while caffeine trended toward a lactate increase (g = 0.24, 95% CrI [-0.48, 0.96]). No credible differences in heart rate were observed across any condition.

SUCRA rankings consistently placed CAF+TAU at or near the top across most outcome domains, reinforcing the multi-pathway advantage of combining central nervous system stimulation (caffeine's primary mechanism) with taurine's neuromodulatory, antioxidant, and calcium-signaling roles. Effects on aerobic endurance and broader physiological indices were variable and context-dependent, suggesting that individual factors — training status, exercise modality, and dosing timing — may moderate outcomes substantially. The authors propose that the combination is particularly suited to high-intensity, reaction-based sports tasks.

Several caveats are important for interpretation. Only 12 studies were included, limiting statistical power for subgroup analyses. Most were crossover designs with small samples, and heterogeneity in dosing (CAF ranges roughly 3–6 mg/kg; TAU 1–3 g) complicates dose-response conclusions. The Bayesian framework handles sparse networks well but introduces prior-sensitivity considerations. Nonetheless, this meta-analysis provides the clearest evidence to date that CAF+TAU co-supplementation is superior to either alone for short-duration, high-intensity and cognitively demanding tasks, offering practical guidance for athletes, clinicians, and energy product formulators alike.