Alpha-glycosyl isoquercitrin (AGIQ) is a highly bioavailable derivative of quercetin, a flavonoid found in various fruits and vegetables. AGIQ is formed by enzymatically attaching glucose units to isoquercitrin, which significantly improves its water solubility and absorption in the body. Quercetin and its derivatives have been studied for their vascular protective properties, particularly their ability to support the health and integrity of capillaries and the microvascular system.

Scientific research indicates that quercetin can strengthen capillary walls, reduce capillary permeability, and exert antioxidant and anti-inflammatory effects that are beneficial to vascular health. Several animal and cell-based studies suggest that quercetin and some of its glycosylated forms, including isoquercitrin and AGIQ, can decrease oxidative stress and inflammation in blood vessel tissues, which may help maintain capillary function. Human research is more limited but has shown modest improvements in vascular function and markers of endothelial health with quercetin supplementation.

The enhanced bioavailability of AGIQ compared to standard quercetin gives it a theoretical advantage for delivering these benefits. However, direct clinical evidence specifically evaluating AGIQ for "capillary support" in humans is limited, and most supportive data are extrapolated from studies on quercetin and related compounds. Thus, while scientific rationale exists and some preliminary evidence supports the use of AGIQ for vascular and capillary health, the overall level of clinical evidence is moderate.