Kiehl's Dermatologist Solutions Powerful-Strength Line-Reducing Concentrate has the following features: Formulated with a high concentration of 10.5% Pure Vitamin C (L-Ascorbic Acid) known for its affinity with skin and its powerful ability to improve the appearance of skin aging. With continued use over time, this treatment has a significant and progressive effect on marionette lines around the mouth and sub-orbital wrinkles in the eye area as well as other facial lines and wrinkles. Skin shows a noticeable improvement in texture and radiance. How to use: Cleanse skin thoroughly prior to application. Apply over entire face twice daily (avoiding the eye area). Can be used alone or layered under your usual moisturizer. In case of contact with eyes, rinse thoroughly. As the formula blends into the skin, you may experience a feeling of warmth. This sensation is normal.