Pine bark extract, particularly from Pinus pinaster (maritime pine), is widely recognized for its antioxidant properties due to high levels of proanthocyanidins. Scientific studies have investigated its effects on vascular health, including the capillary system. Several clinical trials and reviews report that pine bark extract can strengthen capillary walls, reduce capillary permeability, and improve microcirculation. For instance, research published in Phytotherapy Research (2012) and Angiology (2002) found that supplementation with pine bark extract improved symptoms in patients with chronic venous insufficiency, a condition involving weakened capillaries and blood vessels.

The mechanism is primarily attributed to the antioxidant and anti-inflammatory effects of proanthocyanidins, which protect endothelial cells (the cells lining blood vessels and capillaries) from oxidative damage and inflammation. Additional studies suggest pine bark extract reduces swelling, bruising, and leakage from capillaries in conditions like edema and varicose veins. While more large-scale research is warranted, the current evidence base is robust compared to many other botanical ingredients, justifying its use to support capillary health. Its effectiveness for other vascular concerns, such as improving circulation or reducing blood pressure, is also under active investigation.