For thousands of years, practitioners of traditional Chinese medicine have used a medicinal mushroom known as cordyceps to fight fatigue and stimulate the immune system. Now widely available in supplement form, cordyceps is gaining popularity as a natural energy-booster and performance-enhancer.
So far, few clinical trials have looked at whether cordyceps can lift energy and improve exercise performance. While some research suggests that the antioxidant-rich mushroom can increase endurance, other studies show that cordyceps may be of little benefit to athletes.
Still, preliminary research indicates that cordyceps may hold promise for certain health conditions. In tests on animals, for instance, scientists have shown that the inflammation-fighting remedy may help protect against insulin resistance and slow up the aging process. What's more, there's some evidence that other medicinal mushrooms (such as maitake) may rev up immune defense and help fend off colds and flu.