A number of recent endurance exercise studies have looked into the possible benefits of the supplement quercetin, and several have produced intriguing results, says a news item on Runnersworld.com. One particular experiment used experienced cyclists who took quercetin for three weeks and then did three days of cycling for three hours a day. Wow. The quercetin seemed to have no effect on their various muscle enzymes, but did decrease certain blood markers that normally increase with hard exercise, which means the cyclists’ immunity profile improved. Keep an eye on this supplement as more information comes forward.