Background: Caffeine is a well-established ergogenic aid, yet most experimental evidence is based on isolated caffeine, whereas habitual intake in both the general and physically active populations occurs mainly through coffee. This gap between experimental models and everyday practice complicates the interpretation of existing findings. Objective: This review compares coffee and isolated caffeine as ergogenic aids, focusing on biological mechanisms, methodological differences, tolerability, and context-dependent use in sport and exercise. Methods: A narrative review of human studies examining the effects of coffee and isolated caffeine on exercise performance, fatigue, and post-exercise recovery was conducted, with attention being paid to dosing accuracy, bioavailability, inter-individual variability, and the influence of the coffee matrix. Results: Isolated caffeine consistently improves performance under controlled conditions. Coffee can produce similar ergogenic effects, particularly in endurance exercise, although responses are more variable due to differences in caffeine content and individual sensitivity. Emerging evidence suggests that coffee, especially when consumed with carbohydrates, may support post-exercise glycogen resynthesis. Coffee also appears to be better tolerated by many individuals and provides additional bioactive compounds with antioxidant and anti-inflammatory properties. Conclusions: Coffee and isolated caffeine should not be viewed as interchangeable ergogenic strategies. While isolated caffeine remains useful in experimental settings, coffee represents a more ecologically relevant and potentially safer source of caffeine in applied practice. Further direct comparative studies are needed to clarify their context-specific roles.
Przemysław Domaszewski (Tue,) studied this question.