Caffeine under the microscope: Performance booster, dehydration culprit, or misunderstood molecule?

Caffeine remains one of the most widely consumed and debated ergogenic aids in sports and daily life. While its stimulating effects on the central nervous system are well-documented, confusion persists around its real-world benefits and risks. This review critically evaluates common misconceptions about caffeine supplementation, especially in the context of athletic performance, hydration, cardiovascular health, and tolerance development.

A primary myth addressed is the notion that caffeine causes dehydration. Contrary to popular belief, current evidence shows that habitual caffeine consumption in moderate doses does not lead to significant fluid loss or electrolyte imbalance. Another widespread concern involves caffeine-induced diuresis and its impact on endurance athletes. However, multiple studies confirm that the ergogenic effects of caffeine—such as increased alertness, reduced perceived exertion, and enhanced muscular endurance—outweigh any transient increase in urine output.

The article also explores the relationship between caffeine and cardiovascular parameters, emphasizing that the increases in heart rate and blood pressure are generally mild and transient in regular consumers. Importantly, individualized responses—shaped by genetics, habitual intake, and training status—can significantly influence efficacy and tolerance. This makes blanket recommendations problematic and highlights the need for personalized strategies when using caffeine as a supplement.

In the era of biohacking and functional performance, does caffeine deserve a more nuanced reputation? Perhaps it’s time to reconsider our assumptions and leverage its benefits with evidence-based precision—whether you’re chasing a personal best or just a sharper morning mindset.