Quercetin UltraSorb contains the patented QuerceFit quercetin-phospholipid complex forenhanced absorption and bioavailability. The proprietary phytosome technology combines quercetin from Sophora japonica flower extract and phospholipids from sunflower in a 1:1 ratio, promoting resistance to degradation in the digestive tract and efficient absorption across membranes. A randomized crossover human pharmacokinetic study compared QuerceFit with regular quercetin and found the phytosome improved the bioavailability of quercetin by 20-fold. Quercetin is a polyphenolic flavonoid known to exhibit cellular and immune-moderating activity. Research suggests that quercetin acts as a SIRT1 inducer to promote cellular regulation and autophagy, the natural process of degradation and recycling of cellular components to promote renewal. It also increases the body's antioxidant capacity in part by regulating levels of glutathione. In a pilot trial involving adults, supplementation for 30 days with 250 mg or 500 mg Quercetin Phytosome (QuerceFit) quercetin phytosome supported antioxidant defenses and helped support respiratory function and nasal comfort.6 Preliminary research suggests that quercetin helps to stabilize mast cells and moderate the release of immune mediators.