Aescin, the primary active compound in horse chestnut seed extract (Aesculus hippocastanum), is widely used to support capillary and vascular health. Its use is backed by scientific research, especially in the context of chronic venous insufficiency (CVI) and related conditions such as varicose veins and edema. Multiple randomized, placebo-controlled trials have demonstrated that aescin can reduce capillary permeability, improve venous tone, and decrease swelling in the lower limbs. The mechanism of action is thought to involve anti-inflammatory effects, reduction of capillary fragility, and inhibition of enzymes (such as hyaluronidase) that break down capillary walls.

Systematic reviews and meta-analyses, including those published in the Cochrane Database, support the efficacy of horse chestnut seed extract in improving objective and subjective symptoms of CVI, such as leg pain, heaviness, and fluid retention. The evidence is considered moderate to strong, with some guidelines in Europe recognizing aescin as a treatment option for venous disorders. While most studies focus on venous insufficiency, the benefits are attributed to the strengthening and protection of the capillary system. Safety profiles are generally favorable when standardized extracts are used appropriately.

In summary, aescin’s support for the capillary and vascular system is not only traditional but also scientifically validated, with a robust body of clinical evidence supporting its efficacy in improving capillary integrity and function.