Chronic fatigue syndrome is a complex series of symptoms with uncertain etiologies. Quercetin has shown numerous mechanisms of action that might make it a candidate for consideration in cases of chronic fatigue syndrome – antioxidant, anti-inflammatory, immune-modulating, improved exercise endurance, and increased mitochondrial biogenesis and function. Therefore, a well-absorbed form of quercetin was tested for efficacy in individuals suffering from chronic fatigue.
In this study, 78 participants (average age 56; female=42; male=36) complaining of various aspects of chronic fatigue were randomized to receive 250 mg quercetin phytosome or placebo twice daily for two months. Potential participants with an identifiable cause of fatigue like hypothyroidism or anemia were excluded. The primary endpoint was a change from baseline in scores on the Fatigue Impact Scale (FIS-40). Secondary endpoints included sleep quality (measured by the Pittsburgh Sleep Quality Index), quality of life scores, and physical performance and endurance via several physical tests.
At the end of the study, changes in scores on the various tests were compared between the supplement and placebo groups. The quercetin group had significantly greater improvement compared to placebo on the primary endpoint using the FIS-40 score to assess aspects of fatigue. The supplement group also had comparatively and significantly greater improvement in sleep quality and physical performance/endurance. The specific areas of physical performance improvement included number of steps (measured by an armband sensor), gait speed, chair-stand test, and time-up-and-go (the time it takes to stand from an armchair, walk three meters, walk back, and sit down).
