Kiehls iconic anti ageing vitamin C serum, Powerful-Strength Line-Reducing Concentrate, boosts radiance, helps firm skin and visibly reduces fine lines, wrinkles and pores for smoother looking skin. Reformulated with 12.5 percent vitamin C and hyaluronic acid, this patented serum is water free and is one of Kiehls most iconic products. Powerful-Strength Line-Reducing Concentrate targets all the visible signs of ageing: Instantly smoothes the skin surface, Reduces the appearance of fine lines and wrinkles, Improves skin texture, Boosts radiance. Kiehls became a pioneer of vitamin C skin care products when it began to stabilise vitamin C in its serum. Kiehls serum contains highly stable vitamin C, which ensures that it holds an effective amount of vitamin C while also being suitable for sensitive skin. Vitamin C in the formula penetrates all superficial and deeper layers of skin penetrating up to 10 layers deep.