Unopened. My mother used and loved this product for a long time, so I bought the large size. However, I later developed an allergic reaction to an ingredient and had to stop using it. This is a beauty serum containing high concentrations of Vitamin C, which supports skin health. - Brand: Obagi - Product Name: Vitamin C Serum - Size: Large Size - Volume: 26ml - Purpose: Beautiful skin and anti-aging care Thank you for looking.