Flavonoids, a diverse group of plant compounds found in fruits, vegetables, tea, and wine, are widely recognized for their beneficial effects on the vascular system, including capillaries. Multiple scientific studies have demonstrated that flavonoids possess antioxidant, anti-inflammatory, and vasoprotective properties. These compounds help stabilize capillary walls, reduce permeability, and enhance microcirculation. For example, specific flavonoids such as diosmin, hesperidin, and rutin have been shown in clinical trials to reduce symptoms of chronic venous insufficiency and to decrease capillary fragility and edema. Mechanistically, flavonoids scavenge free radicals, inhibit enzymes that degrade connective tissue, and modulate inflammatory pathways that can weaken capillary walls.

Systematic reviews and meta-analyses support the use of flavonoid mixtures in improving symptoms related to capillary dysfunction, including leg swelling and easy bruising. The European Medicines Agency and other health authorities recognize certain flavonoids as traditional herbal medicinal products for these indications, but much of the evidence also meets modern scientific standards. While not all flavonoids are equally effective, and high-quality research is still ongoing, the preponderance of evidence supports their role in maintaining capillary health and function.