Cordyceps, a genus of parasitic fungi, has a long history of use in traditional Chinese medicine for enhancing vitality and combating fatigue. In modern times, its reputation for supporting endurance and athletic performance has been evaluated scientifically. Several studies, primarily small-scale human trials and animal research, have investigated cordyceps’ effects on exercise capacity and fatigue reduction. For example, a few double-blind, placebo-controlled studies have shown that supplementation with Cordyceps sinensis or its cultured analogs can modestly improve oxygen utilization (VO₂ max) and exercise performance in healthy adults and older individuals. These effects are attributed to possible improvements in cellular ATP production and antioxidant activity, as well as enhanced blood flow and anti-inflammatory properties.

However, the quality and consistency of the evidence are mixed. Some studies found no significant benefit, particularly in trained athletes, suggesting that effects may be more noticeable in sedentary or older populations. While the traditional use of cordyceps for improving stamina supports its modern application, the current scientific evidence is moderate and not universally conclusive. Larger, high-quality clinical trials are needed to confirm the extent and mechanism of cordyceps' effects on endurance. Overall, the scientific evidence justifies cautious optimism, but cordyceps should not be considered a replacement for established endurance-enhancing strategies.