Horse Chestnut Herb – BioPeptide Brightening Serum is also infused with horse chestnut extract which strengthens capillaries and acts as an antioxidant to inhibit collagen and elastin destruction. A 20% concentration of l- ascorbic acid (vitamin C) and peptides round out this anti-aging powerhouse to stimulate collagen production, increase skin firmness and repair wrinkles. The result is more resilient, luminous, younger-looking skin.