SkinCeuticals® Retinol 1.0 contains the highest concentrations of pure retinol, to revitalize the skin and help diminish signs of aging. Retinol is one of the only proven ingredients to actually improve fine lines and wrinkles, which is why it is such a sought after skincare ingredient. It is also ideal for congested and/or acne prone skin. Due to the strength of Retinol, it is normal to expect some slight peeling and/or redness when first starting this product. Retinol 0.5 can be used from once a week, up to once a day.