Sunday Riley C.E.O. Vitamin C Brightening Serum uses a sophisticated, ultra-powerful form of Vitamin C called THD Ascorbate. Both highly stable and oil-soluble, THD Ascorbate rapidly absorbs into the skin for visible anti-aging benefits, including visual improvement in loss of firmness, the appearance of lines and wrinkles, and dark spots and dullness. This hydrating antioxidant formula instantly illuminates the complexion with bright radiance, while phytosterols help to reduce the look of skin sensitivity. Saccharide Isomerate extract diminishes the appearance of pores and reinforces the skin's moisture barrier for a skin-smoothing glow. Rapidly brighten the appearance of the skin and boost vital skin bounce, in a flash!